September-October, 2022 Vol, 28 No. 5

CONTENTS PAGE NO. TITLE 07 From the DESK of Chief Editor 08 From the DESK of Managing Editor Subspeciality Cornea 09 36 55 Non-Commercial Drug Formulations for Corneal Infections 15 42 60 Calotropis Procera Latex Induced Keratopathy 19 30 Fungal Keratitis 45 50 Pediatric Keratitis: The salient Points in Management 63 Perspective on Keratopigmentation: The Traditional and The Novel Uses 69 73 78 81 82 86 Refractive Options in High Myopia SMILE (Small Incision Lenticule Extraction) - Newer Developments Liquid Cornea: Fact or Fiction? Intrastromal Copper Wire Graft Insertion Devices in DMEK Unilateral Pathological Keratinization: A Skinful Eye Toxic Anterior Segment Syndrome (TASS) Viral Keratitis TASS and IOLs - Does any relationship exist? Missed Anterior Segment Intra Ocular Foreign Body: Fungal Keratitis masquerading as Viral Keratitis Reading Pentacam for Refractive Procedures Fungal Keratitis - A Potpourri of Interesting Cases

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 DOS EXECUTIVE MEMBERS (2021-2023) 03 Dr. Pawan Goyal Immediate Past President Dr. Om Prakash Anand Prof. Jeewan S. Titiyal Prof. Subhash C. Dadeya Dr. Prafulla Kumar Maharana Dr. Rajendra Prasad Vice President Dr. Gagan Bhatia Prof. M. Vanathi Prof. Namrata Sharma Dr. Amar Pujari Dr. Jatinder Singh Bhalla Secretary Dr. Vivek Gupta Dr. Bhupesh Singh Dr. Sandhya Makhija Joint Secretary Dr. Vivek Kumar Jain Dr. Pankaj Varshney Dr. Alkesh Chaudhary Treasurer Prof. Kirti Singh Editor Dr. Jatinder Bali Library Officer DOS Office Bearers Executive Members DOS Representative to AIOS Ex-Officio Members Dear DOS Members We are sending you DOS TIMES, September-October issue of previous executive tenure. Dr. Rajendra Prasad Dr. Jatinder Singh Bhalla President DOS Secretary DOS

Know Your Editor Managing Editor DOS Times Chief Editor DOS Times Dr. Jatinder Singh Bhalla MS, DNB, MNAMS Hony. General Secretary Delhi Ophthalmological Society DDU Hospital, Hari Nagar Dr. Prafulla Kumar Maharana, MD Associate Professor of Ophthalmology Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 04 Section Editor - Retina & Uvea Prof. (Col) Sanjay Kumar Mishra, HOD, Dept of Ophthalmology (vitreo retina surgeon), Army Hospital (R&R) Section Editor - Retina & Uvea Dr. Alkesh Chaudhary MBBS, MS, FMRF Head Consultant M.D. Eye Care & Laser Centre Section Editor - Uvea & Ocular Inflammatory Disorders Dr. Naginder Vashisht MD, FRCS, FICO Director & Senior Consultant Ophthalmology, Kailash Eye Care, Patel Nagar, New Delhi Senior Consultant Ophthalmology, Artemis Hospitals, Gurugram Section Editor - Retina & Uvea Dr. Raghav Malik, MS Fellowship Cataract & Refractive Surgery Associate Consultant Dept of Cataract, Cornea & Refractive Services, CFS, New Delhi Section Editor - Uvea & Ocular Inflammatory Disorders Dr. Prateek Kakkar (Retina Specialist), MD Ex-Senior Resident (Vitreo-retina, AIIMS, New Delhi) Section Editors - Retina & Uvea Dr. Deepankur Mahajan MBBS, MD (AIIMS), FICO, FAICO (Retina and Vitreous) Consultant Ophthalmologist and Vitreoretina Specialist, New Delhi Section Editor - Uvea & Ocular Inflammatory Disorders Dr. Aman Kumar MD, Senior Resident Vitreo-Retina, Uvea, ROP services Dr. R P Centre for Ophthalmic Sciences, AIIMS, New Delhi Section Editor - Retina & Uvea Dr. Rushil Kumar Saxena Dept of Vitreoretina Dr. Shroff’s Charity Eye Hospital, New Delhi Section Editor - Retina & Uvea Dr. Ankur Singh Assistant professor Dept of Ophthalmology University College of Medical Sciences and GTB Hospital, Delhi Section Editor - Retina & Uvea Dr. Abhishek Jain D.O., D.N.B., FAICO RBM Eye Institute, Delhi ADK Jain eye hospital, Bhagpat Section Editor - Cornea & External Eye Disease Dr. Sameer Kaushal Senior Consultant & Head (Ophthalmology) Artemis Hospital and PL Memorial Eye Clinic, Gurgaon Section Editor - Cornea & External Eye Disease Dr. Abha Gour Senior Consultant Cornea and Anterior Segment Dr. Shroffs Charity Eye Hospital, New Delhi

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 05 Section Editor - Ocular Surface Dr. Rajat Jain MBBS, MS (Gold Medalist), FICO (UK) Fellow- Cornea and Anterior Segment- LVPEI Hyderabad Section Editor - Cataract & Comprehensive Ophthalmology Dr. Ritin Goyal Director & Cornea, Cataract and LASIK surgeon at Goyal Eye Group of Eye Centers. Section Editor - Refractive Surgery Dr. Manpreet Kaur MD, Assistant Professor Cornea, Cataract & Refractive Surgery Services Dr. R P Centre for Ophthalmic Sciences AIIMS, New Delhi Section Editor - Ocular Surface Dr. Jaya Gupta Consultant Cornea Cataract & Refractive Surgery The Healing Touch Eye Care Centre, New Delhi Section Editor - Cataract & Comprehensive Ophthalmology Dr. Wangchuk Doma Venu Eye Institute and Research Centre Section Editor - Refractive Surgery Dr. Pranita Sahay, MD (AIIMS), FRCS (Glasgow), DNB, FICO, FICO (Cornea), FAICO (Ref Sx) Consultant, CFS, New Delhi Section Editor - Ocular Surface Dr. Abhishek Dave Consultant Cornea, Cataract & Refractive Surgery - CFS, New Delhi Section Editor - Ocular Surface Dr. Amrita Joshi Assistant Professor Department of Ophthalmology Army Hospital (R&R) Section Editor - Cataract & Comprehensive Ophthalmology Dr. Amit Mehtani MBBS, MS, DNB DDU HOSPITAL Section Editor - Ocular Surface Dr. Neeraj Verma MS (Ophthal) Senior Consultant Centre For Eye Care Kirti Nagar, New Delhi Section Editor - Cornea & External Eye Disease Dr. Ritu Nagpal MD Senior Research Associate Consultant, Eye7 Hospitals, Lajpat Nagar, New Delhi Section Editor - Cornea & External Eye Disease Dr. Parul Jain MBBS, MS, FICO, FAICO, MRCSEd Associate Professor GNEC, Maulana Azad Medical College Dr. Jyoti Batra Consultant, Oculoplasty and Ocular Oncology, ICARE Eye Hospital and Post graduate Institute, Noida Section Editor - Oculoplasty & Asthetics Section Editor - Oculoplasty & Asthetics Dr. Rwituja Thomas Grover Consultant Oculoplastics, Orbit, Ocular Oncology and Aesthetics services, Vision Eye Centres, New Delhi Dr. Anuj mehta Consultant and Professor Vardhman Mahavir Medical College and Safdarjung Hospital Section Editor - Oculoplasty & Asthetics Section Editor - Glaucoma Dr. Kiran Bhanot MS, DNB Senior Consultant & Hod GGS Hospital & Indira Gandhi Hospital, Dwarka, New Delhi Section Editor - Glaucoma Dr. Suneeta Dubey Head - Glaucoma Services Medical Superintendent Chairperson - Quality Assurance Dr. Shroff’s Charity Eye Hospital New Delhi, India Section Editor - Glaucoma Dr. Prathama Sarkar Consultant in Eye7 Chaudhary Eye Centre Section Editor - Glaucoma Dr. Kanika Jain MBBS, MS, DNB Senior Resident, Dept of Ophthalmology, DDU Hospital, Hari Nagar, New Delhi. Section Editor - Glaucoma Dr. Shweta Tripathi DNB, MNAMS, FMRF Senior Consultant Glaucoma Services Indira Gandhi Eye Hospital and Research Centre, Lucknow Dr. Kavita Bhatnagar Professor & Head, Dept of Ophthalmology, AIIMS, Basani Phase-2, Jodhpur Section Editor - Glaucoma

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 06 Prof. Swati Phuljhale Dr. R P Centre for Ophthalmic Sciences, AIIMS, New Delhi Section Editor - Strabismus Dr. Gunjan Saluja Ex SR Strabismus, Oculoplasty and Neuro-Ophthalmology services, Dr. R P Centre, AIIMS, New Delhi Section Editor - Strabismus Dr. Suraj Singh Senjam Community Ophthalmology Dr. R P Centre for Ophthalmic Sciences, AIIMS, New Delhi Section Editor - Community Ophthalmology Dr. V Rajshekhar MS, FICO Professor & Consultant Dept of Ophthalmology VMMC & Safdarjung Hospital, New Delhi Section Editor - Community Ophthalmology Dr. Digvijay Singh Affiliation, Noble Eye Care, Gurugram Section Editor - Residents Corner Dr. Vineet Sehgal MBBS, MD Fellowship in Glaucoma Senior Consultant & Incharge Glaucoma Sharp Sight Eye Hospitals Section Editor - Residents Corner Dr. Sima Das Head, Oculoplasty and Ocular Oncology Services Incharge, Medical Education Dr. Shroff’s Charity Eye Hospital New Delhi Section Editor - Ocular Oncology Prof. Bhavna Chawla Professor of Ophthalmology Dr. R P Centre, AIIMS, New Delhi Section Editor - Ocular Oncology Dr. Paromita Dutta Associate Professor Guru Nanak Eye Centre Maharaja Ranjit Singh Marg New Delhi Section Editor - Strabismus Dr. Sumit Monga, Senior Consultant. Pediatric, Strabismus and Neuro-Ophthalmology Services, CFS group of Eye Hospitals, Delhi-NCR Section Editor - Neuro-Ophthalmology Dr. Amar Pujari Assistant Professor Dr. R P Centre for Ophthalmic Sciences, AIIMS, New Delhi Section Editor - Neuro-Ophthalmology Dr. Rebika Dhiman Assistant Professor Strabismus and NeuroOphthalmology services, Dr. R P Centre, AIIMS, New Delhi Section Editor - Neuro-Ophthalmology Dr. Simi Gulati I/C and Specialist Charak palika hospital (ndmc) Moti bagh, New Delhi Section Editor - Glaucoma

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 07 DOS TIMES From the DESK of Chief Editor Dr. J S Bhalla, MS, DNB, MNAMS Secretary Delhi Ophthalmological Society Respected Seniors & Dear Friends Corneal Perspective in Ophthalmology. Ophthalmology has been a progressively growing specialty. Last few decades have dynamically changed the subject with the introduction of microsurgical techniques, high tech introduction in diagnostics and therapeutics, and division of subspecialties in ophthalmology. Each of these distinct subspecialties are now on their own trajectory of further evolution. The current issue is focused on Cornea, Keratorefractive surgery & TASS. Currently 36 million people are blind worldwide. Of these 6.17 million or 2.4 percent cases suffer from blindness and/or visual impairment due to corneal causes. Fortunately majority of corneal blindness is avoidable. Reducing the incidence of corneal blindness involves multipronged approach-strengthening public health program, timely hospitalization, safety measures in work place, proper/timely management of corneal infection and increasing the availability of donor corneal tissue and trained keratoplasty surgeons. This issue has important articles on corneal infections: fungal keratitis,viral keratitis, paediatric keratitis, drug formulations for corneal infections. There are also articles on DMEK, Refractive options in high myopia, SMILE and interpretation of PENTACAM charts. Toxic Anterior Syndrome (TASS) is a rare and devastating complication of intraocular surgery. The recent outbreak of this complication all across the country has given us a rude jolt & brought into focus absence of Registry for reporting & lack of well laid out guidelines for reporting to Materiovigilance programme of India & CDSCO (Central Drugs standard Control Organisation). DOS & AIOS have initiated steps to put in place an effective mechanism to help Indian Ophthalmologists to report their cases so that they can be analyzed & matter can be reported to appropriate Authorities. This will help us in not only alerting fellow Ophthalmologists but also will make Regulatory Authorities to take strict actions including Endotoxin testing in Intraocular devices & medications & remedial measures for the benefit of patients & Ophthalmologists. Eye is window to the world. Cornea is window of that window. Let us keep these windows glittering & shining. Happy reading. Dr. Jatinder Singh Bhalla, MS, DNB, MNAMS Chief Editor - DOS Times, Consultant & Academic Incharge (Ophthalmology) DDU Hospital, Hari Nagar

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 08 DOS TIMES It’s a great pleasure on my part to bring out this special edition of DOS Times focusing on Cornea and Ocular Surface. Corneal disorders are an important cause of preventable blindness in India and in the current edition we have tried our best to cover all the important aspects of corneal disorders. Keratitis is a very common corneal problem that almost all Ophthalmologists come across in their practice. The articles on fungal keratitis and viral keratitis will update the readers on the perfect approach to manage such cases. The article on pediatric keratitis covers a difficult aspect of corneal ulcer management. Concentrated topical antibiotic formulations are often required to be prepared by the users. The article on non-commercial drug formulations for corneal infections will help the readers to learn the technique of preparing topical concentrated drop at their own setup. TASS is probably the most common entity discussed in today’s time in India. In order to help the readers, we have included two articles on this important topic. One is an over view while the other focuses on the association of intraocular lenses and TASS. I hope both these articles will be extremely useful to the readers. Lastly, this issue covers several interesting topics like corneal foreign bodies, keratopigmentation, DMEK insertion devices, corneal keratinization, and corneal refractive procedures. The article on Pentacam will help the readers in understanding the basic concepts of interpretation of corneal topography. In the end I would like to repeat my previous words. Change is an essential part of improvement over time. In spite of all our efforts there will definitely be scope for improvement in future. I would request the readers of this edition to convey us through whatever possible means their valuable suggestions and help us improve further. Besides, I would request all the readers to come forward and send their important works for publication in DOS Times. Dr. Prafulla Kumar Maharana, MD Managing Editor DOS Times, Associate Professor of Ophthalmology Cornea Cataract & Refractive Services Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi Email : [email protected] Dr. Prafulla Kumar Maharana, MD From the DESK of Managing Editor

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 09 Update Toxic Anterior Segment Syndrome (TASS) Ritu Nagpal[1], MD, Chandradevi Shanmugam[2], MD, Prafulla Kumar Maharana[2], MD 1. Consultant, Eye7 Hospitals, Lajpat Nagar, New Delhi. 2. Cornea, Cataract and Refractive Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi. Introduction Phacoemulsification is the most commonly performed cataract surgery in this era. Cataract surgery can affect the cornea in several ways. The complication ranges between mild focal corneal edema to severe form of bullous keratopathy.[1] Although most cases resolves without any sequelae, the immediate post operative course is often disappointing for the patient. Moreover, a dissatisfied patient can lead to undue stress and in some cases legal complications. Toxic Anterior Segment Syndrome (TASS) is one such complication. TASS is a sterile postoperative inflammatory reaction caused by a noninfectious agent that gains entry into the anterior segment at the time of surgery and results in toxic damage to intraocular tissues.[2] Although it was described as early as 1980 as a sterile hypopyon related to a residual polishing compound detected on the surface of intraocular lenses, the term “toxic anterior segment syndrome” was first coined by Monson et al.[3,4] Penetrating keratoplasty Vitrectomy Descemet stripping automated endothelial keratoplasty Triple procedure Deep anterior lamellar keratoplasty Phakic intraocular lenses Table-1 Surgeries other than cataract where TASS have been reported. Etiology It is important to remember that identifying a specific cause of TASS is often difficult because of the wide range of patient Alternative terms used for TASS includes toxic lens syndrome, sterile postoperative endophthalmitis, sterile hypopyon, toxic endothelial cell destruction syndrome and localized endophthalmitis.[5] Epidemiology The incidence of TASS is largely unknown. It usually occurs sporadically most of which are under reported. Overall, an estimated incidence of more than 1 in 1000 after cataract surgery can be considered from the available literature.[5] The data from India is limited. Sengupta et al., at the Aravind Eye Hospital reported 60 eyes with TASS from 26,408 consecutive cataract surgeries in a retrospective case series over a period of one year accounting for an incidence of around 0.22%.[6] Although phacoemulsification surgery is the most common anterior segment surgery associated with TASS, other procedures have also been linked as highlighted in Table-1 risk factors, equipments and solutions required during surgery. Numerous causes have been described in the literature as summarized in Table-2. Categories Agents Possible Mechanism Precautions Solutions and IOLs • NaOH • Heavy metals (aluminum, brass, copper, iron, zinc and nickel) • Polishing compounds • Packaging Residual chemicals including heavy metals during polishing or packaging and the nature of the lens might result in water-soluble inflammatory agents penetrating the lens causing a postoperative Appropriate checks and quality control by manufacturers Table-2 Possible risk factors and their mechanism of TASS.

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 10 Categories Agents Possible Mechanism Precautions Surgical instrument contamination • Improper cleaning • Ethylene oxide gas sterilization of surgical tubing lines Residual chemicals and endotoxins cause inflammation Proper training in handling, cleaning, and sterilization of intraocular surgical instruments should be mandatory for the staff involved Ocular viscoelastic materials • Protein and nucleic acids • Bacterial endotoxins Protein and nucleic acids can elicit inflammatory response If reusable irrigation and aspiration cannulas are not cleaned thoroughly after surgery, the residual denatured OVD may be contaminated by heat-stable bacterial endotoxins Appropriate check and quality control by manufacturers Use of disposable cannulas Balanced salt solution • Endotoxins • Cytosol • Endosol • Refrigerated BSS Solution could become a vehicle for toxic material due to an abnormal ionic composition, temperature, osmolarity, or pH Refrigerated BSS may decrease tissue swelling and allow entry of potential toxic subconjunctival fluids Appropriate checks and quality control by manufacturers Intracameral Antibiotics • Cefuroxime • Gentamycin • Moxifloxacin • Vancomycin • Cefazolin • Ceftazidime Toxicity from the drug itself or from preservatives and abnormal pH or osmolality. Contaminants or human error such as improper mixing, dosing or handling Appropriate checks and quality control by manufacturers Standard SOPs for preparation of intracameral drugs Anesthetics • Lidocaine • Tetracaine • Bupivacaine Toxicity from the drug itself or from preservatives and abnormal pH or osmolality. Appropriate checks and quality control by manufacturers Intraocular dye • Trypan blue • Indocyanine green Use of higher concentration or impurities Appropriate checks and quality control by manufacturers Ointments • Gentamycin sulfate • Bethametasone sodium phosphate Not clear Avoid ointments in patients with additional tight eyes patches Intravitreal injections • Bevacizumab • Aflibercept • Trans-zonular Triamcinolone acetonide Drug can reach the aqueous humor Preservatives • Preservatives • Benzalkonium chloride • Edetic acid 0.1% sodium bisulfite • Metabisulfites • Thimerosal Higher doses Direct toxicity Appropriate checks and quality control by manufacturers Update

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 11 Categories Agents Possible Mechanism Precautions Powdered gloves Contact with instruments and IOL Powder free gloves Enzymatic detergents Many enzymatic detergents contain subtilisin or alphaamylase enzymes as their active ingredient which can act as exotoxins Errors in diluting the detergent, cleaning the machines, and trapping of detergents within the device lumens Removing detergent residues from reusable instruments by immediate flushing with sterile distilled or deionized water. Autoclave Presence of sulfates, copper and silica residues in the autoclave steam moisture because of inadequate maintenance of autoclave steam generators Possible contamination of a poorly maintained sterilizer with bacteria resulting in endotoxin contamination Regular maintenance of the water supply to autoclaves as well as the autoclaves Ultrasonic baths Buildup of bacterial endotoxins If this cleaning instrument is used, it must be completely drained, cleaned and dried after each use Patient’s clinical characteristics Type 2 diabetes mellitus Systemic hypertension Hyperlipidemia Chronic ischemic heart disease Chronic renal failure May increase the risk Exact mechanism not known The American Society of Cataract and Refractive Surgery (ASCRS) TASS Task Force suggested that improper cleaning of surgical instruments is the most common cause of TASS. According to the ASCRS TASS task force, the inadequate flushing of phaco tips and irrigation/aspiration handpieces after surgery were the most commonly observed and reported cause of TASS. The use of reusable cannulas and inadequate or even no manual cleaning of instruments were also observed as important causes. The exact mechanism how these agents cause TASS is not well defined. Tissue toxicity appears to be the final common pathway. The various etiological agents produces tissue toxicity via free radical generation, inflammation and a breach in blood-aqueous barrier. (Figure-1) Figure 1: Pathogenesis of TASS. Update

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 12 Figure 3: Diffuse corneal edema extending from limbus to limbus in the left eye of a patient, same as figure 2, after phakic IOL implantation. Figure 4: Chronic TASS with PAS formation and shallow AC. Figure 2: Diffuse corneal edema extending from limbus to limbus in the right eye of a patient after phakic IOL implantation. Clinical Feature The classic presentation of TASS includes acute onset of decrease in visual acuity, and ocular discomfort associated with limbus to limbus corneal edema, (Figure 1 and 2) and anterior chamber inflammation within the first 12-48 hours after intraocular surgery. The decrease in vision depends upon the severity, usually the visual acuity is in the range of 6/12 to 6/24. However, in severe cases it may be counting fingers only. One peculiar feature is the pain, which is either absent or very minimal. The various clinical signs are summarized in table 2. (Figure 2-4) Differential Diagnosis The most important clinical differential diagnosis is infectious endophthalmitis. The differentiating features are summarized in Table-3. Sometimes a complicated cataract surgery can lead to an increased postoperative inflammation; however, limbus to limbus corneal edema, raised IOP in an uncomplicated cataract surgery often differentiates TASS easily. Table-3 Signs of TASS. Uveitis Anterior chamber cells Aqueous flare Fibrinous inflammation Keratic precipitates Hypopyon Corneal Edema Diffuse “limbus-to-limbus” corneal edema Secondary Glaucoma Initial few hours the IOP may be low due to marked inflammation followed by rise due to trabeculitis. In severe cases, permanent damage to the trabecular meshwork can occur from the toxic substance, chronic trabeculitis, and formation of PAS can lead to chronic glaucoma (Figure-4) Update

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 13 Pupil In acute stage pupil may be fixed and dilated Persistent inflammation can cause iris ischemia and atrophy of the iris sphincter muscle Posterior Segment Usually, no significant posterior segment involvement Spill-over anterior vitritis in some cases Table-4 Differential diagnosis of TASS. Characteristic Endophthalmitis TASS Onset (from day of surgery) >48 hr 12-24 hours Pain Moderate to severe Usually absent Decrease in visual acuity Moderate to severe Mild to Moderate IOP Usually normal Significant increase Corneal edema Mild or absent Severe (limbus-limbus) Fibrin Present Usually none Vitreous involvement Significant haze Usually clear Hypopyon Common Rare Response to steroids Poor Good Response to antibiotics Good Poor Prognosis Poor Usually good Management Prevention is better than cure. There have been several evidence-based guidelines for ophthalmic Instrument cleaning and sterilization by various associations such as Association of Cataract and Refractive Surgeons (ASCRS) (http://www.ascrs. org/tass-registry).[7] The readers could refer to those. Besides as highlighted in Table-1, individual measures to address the various risk factors may help in avoiding TASS. Medical Management Topical steroids are the treatment of choice. Most cases will resolve with topical medication and observation only. Prednisolone acetate 1% drops administered every 1-2 hourly should be started immediately and often effective in controlling the inflammation. Other form of steroids like, ointments, subconjunctival injection, oral Prednisolone or intravitreal triamcinolone or dexamethasone can be tried in case of poor response to topical steroids.[5] IOP is often raised in these cases and a careful monitoring of the IOP is mandatory during the course of inflammation. in most cases IOP can be controlled with topical drops only. It is better to avoid prostaglandin analogues as they may worsen the inflammation.[5] Surgical Surgery is required in rare cases. In cases of severe and persistent inflammation few authors have performed irrigation of the anterior chamber, vitrectomy, and removal of the IOL with variable outcomes.[8,9] Long-term complications of TASS such as corneal endothelial failure, glaucoma may need endothelial keratoplasty and filtering surgeries respectively.[5] Complications The following complications can occur post TASS[5] a. Persistence of corneal oedema due to endothelial decompensation. b. Secondary glaucoma – resulting from trabecular meshwork damage and peripheral anterior synechiae formation due to severe inflammation. c. Fixed dilated pupil – resulting from damage to the iris stromal tissue due to severe inflammation. Prognosis The prognosis of patients with TASS depends upon the severity of the condition and promptness in diagnosis and management. Patients with mild inflammation show good response to steroid therapy with rapid clearing of the cornea (days to weeks). Patients with moderate inflammation take a longer time for the cornea to clear (weeks to months) with slight residual corneal edema. Patients with severe TASS result in permanent damage like persistent corneal oedema requiring corneal transplant. Secondary glaucoma in these cases is usually resistant to medical therapy and require surgical management like trabeculectomy or shunt surgery.[5] Update

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 14 References 1. Sharma N, Singhal D, Nair SP, Sahay P, Sreeshankar S, Maharana PK. Corneal edema after phacoemulsification. Indian J Ophthalmol. 2017 Dec;65(12):1381–9. 2. Sandhu HS. Chapter 20 - Toxic Anterior Segment Syndrome. In: Sandhu HS, Kaplan HJ, editors. Clinical Cases in Uveitis [Internet]. Philadelphia: Elsevier; 2021. p. 81–4. Available from: https://www. sciencedirect.com/science/article/pii/B9780323695411000203. 3. Edelhauser HF, Van Horn DL, Schultz RO, Hyndiuk RA. Comparative toxicity of intraocular irrigating solutions on the corneal endothelium. Am J Ophthalmol. 1976 Apr;81(4):473–81. 4. Monson MC, Mamalis N, Olson RJ. Toxic anterior segment inflammation following cataract surgery. J Cataract Refract Surg. 1992 Mar;18(2):184–9. 5. Hernandez-Bogantes E, Navas A, Naranjo A, Amescua G, Graue-Hernandez EO, Flynn HW, et al. Toxic anterior segment syndrome: A review. Surv Ophthalmol. 2019;64(4):463–76. 6. Sengupta S, Chang DF, Gandhi R, Kenia H, Venkatesh R. Incidence and long-term outcomes of toxic anterior segment syndrome at Aravind Eye Hospital. J Cataract Refract Surg. 2011 Sep;37(9):1673-8. doi: 10.1016/j.jcrs.2011.03.053. Epub 2011 Jul 22. PMID: 21782384. 7. Mamalis N. ASCRS TASS task force: An ongoing journey. J Cataract Refract Surg. 2012 Nov;38(11):1883–4. 8. Oshika T, Eguchi S, Goto H, Ohashi Y. Outbreak of Subacute-Onset Toxic Anterior Segment Syndrome Associated with Single-Piece Acrylic Intraocular Lenses. Ophthalmology. 2017 Apr;124(4):519–23. 9. Kumaran N, Larkin G, Hollick EJ. Sterile postoperative endophthalmitis following HOYA IOL insertion. Eye (Lond). 2014 Nov;28(11):1382. Dr. Ritu Nagpal, MD Consultant, Eye7 Hospitals, Lajpat Nagar, New Delhi. Corresponding Author: Update

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 15 TASS and IOLs - Does any relationship exist? J S Bhalla, MBBS, MS, DNB, MNAMS, Yogesh Kumar, MBBS, Ridhima Sakhuja, MBBS, MS, DNB, FPOS Neha Yadav, MBBS, Ashish Kumar, MBBS, DOMS, Sadiqua Khatoon, MBBS, DOMS, Tarun, MBBS, Karuna Dhepe, MBBS, DOMS, DNB Department of Ophthalmology, DDU Hospital, Hari Nagar, New Delhi. Introduction Toxic anterior segment syndrome (TASS) is an acute postoperative sterile inflammatory reaction of the anterior segment of the eye that most commonly develops after cataract surgery.[1-4] The sterile inflammation occurs in response to noninfectious substances gaining entry into the eye during surgery, causing damage to Intra ocular tissues. Although TASS is a rare complication to occur after Intraocular surgery, the recent outbreak has brought attention to this dreaded complication and the probable implication of Intraocular lenses (IOL) in its causation. Clinical Features and Diagnosis Most cases present early (12-24 hrs after Surgery) but late cases have also been reported.[5] Patients usually present with significant reduction in visual acuity (most common), corneal edema (limbus to limbus), fibrin formation, hypopyon and irregular and fixed pupil. Pain however is not a common feature in patients of TASS. Although diagnosis of TASS is clinical but in doubtful cases, a negative culture for bacteria and fungi, negative polymerase chain reaction (PCR), absence of anyvitreous involvement and positive response to steroids help in differentiating TASS from Endophthalmitis. Incidence Incidence of TASS varies from 0.1 – 2%.[6-7] It usually occurs sporadically or as a cluster of cases. Finding the cause in isolated cases is difficult, but a cluster of cases needs to be reported and investigated. Phacoemulsification surgery is most commonly associated with TASS but other Intraocular surgical procedures like penetrating keratoplasty[8], Descemet stripping automated endothelial keratoplasty triple procedure[9], Deep Anterior Lamellar Keratoplasty[10] and vitrectomy[11] have also been implicated. Risk Factors[12-13] Systemic Ocular Diabetes Mellitus Proliferative Diabetic Retinopathy Hypertension Pseudo-exfoliation Hyperlipidemia History of Uveitis Chronic Ischemic Heart Disease Chronic Renal Failure Figure 1: Shows bulging pupilary membrane. Figure 2: Shows fibrinous strand with minimal AC reaction. Update

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 16 Causes[5] Impurity Present Ocular Viscoelastic devices (OVD) • Protein and Nucleic Acid • Residual Denatured OVDs in reusable cannulas Balanced Salt Solution (BSS) • Abnormal ionic composition, temperature, osmolarity or pH Antibiotics • Preservatives • Mixing Antibiotics into BSS Anesthetic • Preservatives Intra Ocular Dye • Impurities • Insufficient washout Intra-Vitreal Injection • Seepage in Anterior Chamber Sterilization • Enzymatic detergent • Trapping of Subtilisin and alphaamylase enzymes. • Autoclaving • at 120°C - Heat Stable endotoxins remains active, • Suboptimal maintenance of steam generator • Ultrasonic bath • Incompletely drained or cleaned Preservatives • Benzalkonium chloride (0.01% and 0.1%) • Edetic acid • Sodium bisulfite (0.1%) • Thimersal (0.01%) Powdered Gloves • Corn starch powder IOL as a Causative Factor The solution used for preservation, the method of sterilization, the composition and design of the IOL and the residual impurities in it have all been implicated in the causation of TASS.[5,13] Contamination of IOLs leading to ocular inflammation can be due to the presence of of ocular inflammation can be due to the presence of heavy metals (Aluminium, Brass, Copper, Iron, Zinc and Nickel) on the IOL surface, residual polishing compounds on the surface, and a rough lens texture increasing the risk of deposit of foreign material. Sub-optimal quality of instruments, solutions and raw materials used in the manufacturing, sterilization and packaging are hypothesized to cause TASS. Reported By Year and Number of Cases Reported Type of Lens Company/Model of IOL Inciting Agent Miyake et al[14] 2015 (6) Hydrophobic ISert model 251 Aluminium contamination Suzuki et al[13] 2015 (251) Hydrophobic Hoya, ISert model 251 & 255, Intraocular lens contaminated with aluminum Oshika et al[4] 2016 (147) Hydrophobic AcrySof ReSTOR, ReSTOR toric, or AcrySof IQ toric, Model SN6AT6-9, Alcon Small heavy metals during the production process of the intraocular lens Jehan et al[15] 2000 (10) Hydrophobic MemoryLens-model U940A and U940S; CIBA Vision Residual polishing compound Imamachi et al[16] 2021 (7) Hydrophobic Lentis Comfort LS-313 MF15 Reason not clear (current outbreak) 2022 (n) Hydrophilic Under investigation Under investigation Update

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 17 Figure 3: On the left showing Fibrinous reaction and corneal edema (post-op day 1), on the right (after dilatation) shows irregularly dilated pupil and dense fibrinous reaction. Prevention TASS as a post-operative complication can be avoided by bearing all preventive measures in mind and following them carefully and consistently. Some of the measures that should be adopted include discouraging the use of enzymatic detergents, autoclaving of instruments at higher temperature of 140° (endotoxins are also destroyed), using disposable cannulas, preservative free antibiotics and anesthetics, and using distilled water for instruments cleaning and autoclaving of instruments. In a cluster of cases one needs to thoroughly examine and investigate to find the cause. Aravind Eye Hospital[23] has provided a protocol for determining the etiology of TASS. Association of cataract and refractive surgeons (ASCRS)[17] recently provided an evidence-based recommendation regarding cleaning and sterilization of intraocular instruments.[17,18] Management Majority of cases resolve with intense topical steroid therapy alone. Prednisolone acetate 1% is administered every 1-2 hours for the first few days and then tapered gradually.[13] Sub-conjunctival steroid injection can be given for severe cases. Refractory TAAS not responding to any steroid therapy can benefit from recombinant tissue plasminogen activator (r-tPA) injections[19] or removal of fibrinous membrane surgically by irrigation of anterior chamber. For cases with corneal decompensation, endothelial keratoplasty or penetrating keratoplasty can be performed.[20,21] Complication The outcome and prognosis of cases of TAAS depends on various factors which include severity of inflammation, amount & type of the toxic substance, the duration of exposure, time of presentation and adequacy of treatment.[5] Most cases of TASS have reported[4,5,22] a good outcome however few develop complications mainly due to factors like acute and persistent inflammation, reduction in endothelial cell density, persistent corneal edema, cystic epithelial downgrowth, secondary glaucoma due to inflammation induced trabeculitis or angle closure due to posterior synechiae, fixed and unresponsive pupil and cystoid macula edema.[1,22] Reporting The fundamental role of reporting an adverse event is to enhance patient safety and ensure better future outcome. Under the Medical Device Rules, 2017 (MDR), IOLs have been notified as drugs and are regulated by Central Drugs Standard Control Organization (CDSCO) (National Regulatory Authority of India).[23] The Materiovigilance Programme of India (MvPI), launched by the Ministry of Health and family Welfare, Govt. Of India generates evidence-based information on the safety of medical devices and analyses the benefit-risk ratio to create a nation-wide system for patient safety and monitoring.[24] Reporting should also be done to the State Ophthalmic Society, National Ophthalmic Society and to the manufacturer, so that necessary regulatory decisions should be taken. In the west, when TASS cases were found to be due to the endotoxin contamination of BSS, the FDA had reduced the limit of endotoxins from 0.5 to 0.2 EU/ml.[25] As the adverse event reports related to a device increase, essential investigations about the product can be initiated which may result in modifications to the product or changes in the current guidelines. Disclaimer The authors doesn’t encourage or discourage the use of mentioned products or brands. Update

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 18 References 1. Mamalis N, Edelhauser HF, Dawson DG, et al. Toxic anterior segment syndrome. J Cataract Refract Surg. 2006;32:324-333. 2. Mamalis N. Toxic anterior segment syndrome update. J Cataract Refract Surg. 2010;36:1067-1068. 3. Bodnar Z, Clouser S, Mamalis N. Toxic anterior segment syndrome: update on the most common causes. J Cataract Refract Surg. 2012;38:1902-1910. 4. Oshika, T., Eguchi, S., Goto, H., & Ohashi, Y. (2017). Outbreak of Subacute-Onset Toxic Anterior Segment Syndrome Associated with Single-Piece Acrylic Intraocular Lenses. Ophthalmology, 124(4), 519– 523. 5. Hernandez-Bogantes, E., Navas, A., Naranjo, A., Amescua, G., Graue-Hernandez, E. O., Flynn, H. W., & Ahmed, I. (2019). Toxic Anterior Segment Syndrome: A Review. Survey of Ophthalmology. 6. Baneke AJ, Lim KS, Stanford M. The Pathogenesis of Raised Intraocular Pressure in Uveitis. Curr Eye Res. 2016;41(2):137e49 7. Bhagat N, Grigorian RA, Tutela A, Zarbin MA. Diabetic macular edema: pathogenesis and treatment. Surv Ophthalmol. 2009;54(1):1e32 8. Maier P, Birnbaum F, Bohringer D, Reinhard T. Toxic anterior segment syndrome following penetrating keratoplasty. Arch Ophthalmol. 2008;126(12):1677e81 9. Sorkin N, Varssano D. Toxic Anterior Segment Syndrome following a Triple Descemet’s Stripping Automated Endothelial Keratoplasty Procedure. Case Rep Ophthalmol. 2012;3(3):406e9 10. Sevimli N, Karadag R, Cakici O, et al. Toxic anterior segment syndrome following deep anterior lamellar keratoplasty. Arq Bras Oftalmol. 2016;79(5):330e2 11. Andonegui J, Jimenez-Lasanta L, Aliseda D, Lameiro F. [Outbreak of toxic anterior segment syndrome after vitreous surgery]. Arch Soc Esp Oftalmol. 2009;84(8):403e5 12. Yazgan S, Celik U, Ayar O, et al. The role of patient’s systemic characteristics and plateletcrit in developing toxic anterior segment syndrome after uneventful phaco surgery: A case-control study. Int Ophthalmol. 2017;38(1):43e52 13. Suzuki T, Ohashi Y, Oshika T, et al. Outbreak of late-onset toxic anterior segment syndrome after implantation of one-piece intraocular lenses. Am J Ophthalmol. 2015;159(5):934e9.e2 14. Miyake G, Ota I, Miyake K, et al. Late-onset toxic anterior segment syndrome. J Cataract Refract Surg. 2015;41(3):666e9 15. Jehan FS, Mamalis N, Spencer TS, et al. Postoperative sterile endophthalmitis (TASS) associated with the memorylens. J Cataract Refract Surg. 2000;26(12):1773e7 16. Imamachi, K., Sugihara, K., Ikeda, Y., Matsuoka, Y., & Tanito, M. (2021). Report of a Cluster of Cases of Toxic Anterior-segment Syndrome After Implantation of a Specific Intraocular Lens Model. American Journal of Ophthalmology, 228, 1–7 17. http://www.ascrs.org/tass-registry 18. American Society of C, Refractive S, American Society of Ophthalmic Registered N. Recommended practices for cleaning and sterilizing intraocular surgical instruments. Insight. 2007;32(2):22e8 19. Dotan A, Kaiserman I, Kremer I, et al. Intracameral recombinant tissue plasminogen activator (r-tPA) for refractory toxic anterior segment syndrome. Br J Ophthalmol. 2014;98(2):252e5 20. Pineda R 2nd, Jain V, Gupta P, Jakobiec FA. Descemet’s stripping endothelial keratoplasty: an effective treatment for toxic anterior segment syndrome with histopathologic findings. Cornea. 2010;29(6):694e7 21. Suzuki T, Ohashi Y, Oshika T, et al. Outbreak of late-onset toxic anterior segment syndrome after implantation of one-piece intraocular lenses. Am J Ophthalmol. 2015;159(5):934e9.e2 22. Rishi E, Rishi P, Sengupta S, et al. Acute postoperative Bacillus cereus endophthalmitis mimicking toxic anterior segment syndrome. Ophthalmology. 2013;120(1):181e5 23. https://cdsco.gov.in 24. https://nhsrcindia.org/hc-technology/materiovigilance-programme-of-india 25. https://www.fda.gov/files/medical%20devices/published/Endotoxin-Testing-Recommendations-for-Single-Use-Intraocular-Ophthalmic-Devices---Guidance-for-Industry-and-Food-and-Drug-Administration-Staff.pdf Dr. Jatinder Singh Bhalla, MBBS, MS, DNB, MNAMS Senior Consultant & Academic Incharge, Department of Ophthalmology, DDU Hospital, New Delhi. Corresponding Author: Update

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 19 Reading Pentacam for Refractive Procedures Sohini Mandal, MD, FAICO, Rajesh Sinha, MD, FIACLE, DNB, FRCS Cornea, Cataract and Refractive services, Dept. of Ophthalmology, Dr. R P Centre for Ophthalmic Sciences, AIIMS, New Delhi. Introduction Pentacam (Oculus, Wetzlar, Germany) is based on Scheimpflug imaging and utilises elevation-based systems. It was introduced in 2003 for commercial use and is one of the most used instruments for corneal tomography. Scheimpflug based devices offer genuine information about both the anterior and posterior surface of cornea and hence are referred to as “corneal tomography” system. Other Scheimpflug based devices includeTMS-5 (Tomey, Nagoya, Japan), Sirius (CSO Florence, Italy), and Galilei (Ziemer, Port, Switzerland).[1] With the increasing demand for refractive surgery, it is of supreme importance to screen these cases swiftly with precision for corneal ectasia prior to surgery.[2] Figure 1: Pentacam (Oculus, Wetzlar, Germany) based on Scheimpflug imaging. Pentacam captures 50 scans in two seconds with 2760 true elevation points per scan and 138,000 true elevations points covering the entire surface of cornea i.e., from limbus to limbus. It precisely estimates the details of anterior and posterior corneal contour, pachymetry, anterior chamber depth and pupil diameter. In addition, it provides the Belin-Ambrosio enhanced Corneal Diagnostics

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 20 Figure 2: Overview report of Pentacam provides the Scheimpflug cross-sectional image, showing the cornea, anterior chamber, iris, and lens. A 3-D representation of the patient’s corneal shape is also provided. ectasia display (BAD) that gives various parameters for detection of forme-fruste keratoconus. All these features have made Pentacam an invaluable tool for anterior segment imaging especially in cases undergoing cornea based refractive surgery and cases of corneal ectasia. The slit images captured by the rotating camera are photographed from 0 to 180-degree angle to avoid shadows from the nose. The machine automatically corrects the small eye movements recorded thus making the examination procedure very comfortable, rapid, and accurate. It also corrects for the distortion caused by the camera optics, cornea, or the lens. The images taken during the scan are digitalized and the data is transferred to the processor which provides a 3D virtual model of the anterior segment. The scan is conducted in dark room and the patient is asked to fixate on the blue light in the centre of the machine. To decrease the operator – dependent variables, the machine has an automatic release mode which automatically determines the correct focus and alignment with the corneal apex and initiates the scan. The machine also has a quality check in the form of quality factor (QS) both for image analysis of anterior and posterior corneal surface and values of >95% are chosen for analysis.[3] Pentacam Interpretation This article will take you through a step-by-step interpretation of 4 composite refractive map and Belin-Ambrosio enhanced ectasia display (BAD) map of Pentacam. 1. Overview Report This report provides the Scheimpflug cross-sectional image, showing the cornea, anterior chamber, iris, and lens. A 3-D representation of the patient’s corneal shape is also provided. (Figure-2) The density of the cornea is evaluated using densitometry, which is an objective measurement of light scatter in the cornea. Any densitometry value <30 is considered normal; thus, any condition resulting in decreased corneal clarity (e.g., corneal edema) will increase the densitometry value. There is also a summary of the keratometry, pachymetry, and other numeric measurements in this report. 2. Quad or 4 maps refractive The 4 maps refractive consists of the following (Figure-3): 1. Sagittal or Axial curvature map (anterior surface of cornea) 2. Anterior/front elevation (anterior cornea). 3. Posterior/back elevation (posterior cornea) 4. Corneal thickness (pachymetry) Key Points to remember before you interpret 4-maps Refractive: Corneal Diagnostics

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 21 Figure 3: The 4 maps refractive showing sagittal/ axial curvature map, anterior/front elevation, posterior/back elevation and corneal thickness/ pachymetry map within normal range. • Patient information details The box on the extreme left top corner contains the information about the patient which includes the age, sex, the date of scan and the date of birth. (Figure-4) • Q value It denotes the sphericity of the anterior corneal surface. (Figure-4) Values 0 to -1: normal and indicates a prolate shape (steep centre and flat periphery) >0: oblate cornea (flat centre and steep periphery) <-1: hyper-prolate cornea as seen in corneal ectasia. • Quality Specification (QS) should be OK in white colour box. Do not interpret map if QS is in yellow (data gaps) or red (blinking) and repeat the measurement. (Figure-4) • The map should be set to 8- or 9-mm display. • Keratometric value within the central 3mm zone in the flat meridian is K1 and in the steep meridian is K2. Km represents the mean keratometric reading of K1 and K2. The maximum keratometric reading of the anterior corneal surface is represented as Kmax. The curvature map shows keratometric power of the anterior corneal surface (central 8 mm) represented in a colour-coded fashion. The hot colours (orange/red) indicate steep corneal contour while cool colours (blue/violet) represent flat corneal contour. A symmetric bow tie pattern is observed in the curvature map of cases with regular astigmatism. (Figure-4) • True net power map represents the cumulative keratometric power of the cornea considering both the anterior posterior corneal contour. • Check if there are extrapolated data in the central 8 mm display. If there are black dots or white areas, then discard the map and take a fresh measurement. • If Kmax is inferiorly displayed such that it is in the periphery, then repeat the measurement. Check if there is any lid interference. • Three pachymetry readings are displayed: “Pachy apex”: corneal thickness at the apex/centre of cornea “Pupil centre pachymetry”: corneal thickness at the pupillary centre “Thinnest location (TL)”: corneal thickness at the thinnest location Pachy apex is considered as the reference point for measuring the displacement of all other pachymetry indices. “X axis” and “Y axis” represents the horizontal and vertical meridian Corneal Diagnostics

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 22 displacement respectively. The plus or minus sign signify the direction being above or below the reference point respectively. (Figure-4) • In pachymetry map, the thickness at different points of the cornea (central 8 mm) is noted. The colour corresponding to various thickness can be seen on the side panel of the chart. Cool colours represent thick cornea while hot colours represent thinning. (Figure-3) Normally, the pachymetry at the apex of the cornea is the thinnest point. A displacement of the thinnest point from the apex of cornea raises suspicion for corneal ectasia if it co-exists with corneal steepening. • Ensure that you have not measured on a misaligned or nonfixating eye. (To rule out that apply the following equation: X+X <0.2; Y-Y <0.2) That is compare the X and Y coordinates of pupil centre of two eyes. The X of pupil centre of right eye plus the X of pupil centre of left eye should be less than 200 microns or 0.2. Similarly, the Y of pupil centre of right eye minus the Y of pupil centre of left eye should be less than 200 microns or 0.2. (If it is >200 microns or 0.2mm, expect misalignment of eye. This is important to rule out false angle kappa). Figure 4: The 4 maps refractive showing patient information characteristics and summary of pachymetry and keratometry values. • Cut-off values 1. The Km (mean K) of the anterior corneal surface should be <48 D. Note this value as shown in Figure 4. 2. In the sagittal curvature map, note the difference in power of two opposite hemi meridians, that is the inferior-superior (I-S) asymmetry. To know this, the dioptric power is recorded at 5 points on the superior and inferior cornea 4 mm from the center at 30-degree interval. (Figure-5A) 3. The inferior value should be 1.5 D lesser than the superior values. A value >1.5 D indicates abnormality. If the superior is more than the inferior by >2.5 D, consider abnormal. Therefore, I-S <1.5 D and S-I <2.5 D are normal. 4. Skewed radial axis (SRAX) is another indicator. In regular astigmatism, there is a symmetry in astigmatism axis between the superior and inferior axis. If the superior and inferior axis is skewed, this is called SRAX. SRAX >22 degree is abnormal. (Figure-5B) 5. Interpreting the elevation maps are key to diagnose early stages of ectasia. The elevation maps are considered abnormal or normal based on its comparison with a Corneal Diagnostics

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 23 reference sphere, often the Best Fit Sphere (BFS) or the Best Fit Toric Ellipsoid (BFTE). Any of the two reference spheres may be applied, but do note that the indices change according to the choice of reference sphere. Points above the reference sphere are considered elevations and expressed in plus values (hot colours), and those below the reference sphere are considered depressions and expressed in minus values (cool colours). (Figure-6) 6. Consider thinnest location of cornea <470 microns as high risk. Values >500 microns may be considered low risk. (Figure 4) 7. The difference between pachymetry apex and thinnest location should be <10 microns. (Figure-4) 8. The Y coordinate of thinnest location should be <-0.5 mm. (Keratoconus is mostly associated with an inferiorly displaced thinnest location. A value of >-0.5 mm is a yellow flag and >-0.1 mm is a red flag. 9. Pentacam gives an accurate assessment of the mesopic pupil diameter (PD) which is essential to screen in patients planned for refractive surgery. Large mesopic PD (>5 mm) results in glare and halos following surgery. (Figure-4) 10. Pentacam creates a 3D model of the eye and estimates parameters like the anterior chamber angle and anterior chamber depth (endothelium to the anterior lens capsule) which is useful in assessing cases of glaucoma and phakic intraocular lenses. It also gives the cornea corrected intraocular pressure value. (Figure-4) An additional software for densitometry assessment gives results for corneal and lens densitometry. Figure 5: (A) The dioptric power is recorded at 5 points on the superior and inferior cornea 4 mm from the centre at 30-degree interval; (B) Radial axes are skewed i.e., when the smallest measured angle between the 2 radial axes of the 2 lobes is >22° Figure 6: Schematic representation of a reference surface (typically, a sphere) superimposed by fitting the reference surface as smooth as possible to the data surface (Best Fit Sphere). Relative elevation measures height difference in microns from a best-fitting reference sphere. In all elevation maps, green is the reference surface or zero level. Red is high and positive. Blue is low and negative. Corneal Diagnostics

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 24 Figure 7: Belin/Ambrosio enhanced ectasia display showing normal colours in the elevation map and difference map. The corneal thickness spatial profile (CTSP) and percentage thickness increase (PTI) are within range as seen by the red line lying within the two black dashed lines however, the thinnest pachy is 481μ, the D value is in the suspicious range with increased PPI and reduced ARTmax. 3. Belin Ambrosio Enhanced Ectasia Display (BAD map) Belin/Ambrósio enhanced ectasia display I map is based on the concept of the Enhanced best fit sphere which is calculated after taking into consideration the keratometric readings of the patient’s cornea. This helps to highlight subtle corneal abnormalities which maybe missed on the elevation map based on the best fit sphere. (Figure-7) The elevation maps are calculated according to the best fit sphere (BFS) and enhanced BFS model in the BAD map display.[4] The enhanced BFS is calculated by determining the BFS from central 8.0 mm zone after excluding all the data from a 3.5-4 mm optical zone centred on the thinnest part of the cornea. The exclusion zone is determined by the magnitude of astigmatism and is not selected by the operator. Finally, it calculates the difference in elevation values between the standard BFS and the enhanced BFS which differentiates between normal and ectatic corneas. It comprehensively evaluates pachymetric values along 22 concentric rings with 0.4 mm incremental increase in diameter centred on the thinnest point. a. Corneal thickness spatial profile (CTSP) The graph represents the progression of the corneal thickness from the TL to the corneal periphery along these concentric rings. The graph is plotted using red dots and it should lie within the three black dotted lines wherein the central line is the average progression derived from normal population and 95% confidence interval is denoted by upper and lower black dotted lines. Any sudden dip or rise within the 6 mm zone is considered abnormal. b. Percentage Thickness Increase (PTI) The graph represents the percentage plot of the above graph. Any sudden dip or rise within the 6mm zone is considered abnormal. c. D value Belin/Ambrósio enhanced ectasia display II consists of 5 parameters including Df (front surface), Db (back surface), Dp (pachymetric progression), Dt (thinnest point) and Dy/Da (thinnest point displacement). Final “D” is calculated by considering all 5 parameters and performing a linear regression analysis against a standard database of normal and KC corneas. The parameter is indicated in: White box (normal) <1.6 SD Yellow box (suspicious) >1.6 SD Red box (abnormal) >2.6 SD However, one should also correlate the age of the patient with the D value as the threshold for suspicion is higher in older age group when compared to young individuals. Belin/Ambrósio enhanced ectasia display III added four additional parameters (K max, anterior and posterior elevation at the thinnest point and Ambrósio relational thickness maximum (ART max) to original regression analysis.[5] Corneal Diagnostics

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 25 1. Pachymetric progression index (PPI) calculates the change in corneal thickness over all 360 degrees of the cornea. The progression value at each meridian from the thinnest point is defined as Progression Index and the average of all meridians is illustrated by PPI-Avg. PPI-Max is the meridian with maximal pachymetric increase. PPI-Min is the meridian with minimal pachymetric increase. A rapid rate of pachymetric progression distinguishes ectatic cornea from normal. 2. Ambrósio relational thickness (ART) is the ratio between the thinnest point and PPI. It includes ART max, ART min and ART avg. The Cut-off value for the diagnosis of KC is 412 microns.[6] It is a validated diagnostic index that distinguishes keratoconic eyes from normal eyes.[7,8] However, there is no consistent value for determining FFKC and pre-keratconus.[9,10] Indices for corneal surface irregularity include: • Index of surface variance (ISV) is measured as the standard deviation of individual sagittal radii from mean curvature. It is a highly sensitive index in differentiating KC from normal eyes.[6] • ISV >37 is abnormal (yellow) • ISV >41 is pathological (red). 3. Index of vertical asymmetry (IVA) is the mean difference (in mm) between superior and inferior corneal curvature, the level of curvature symmetry with respect to the horizontal meridian as the axis of reflection. IVA >0.28 is abnormal, and >0.32 is pathological.[6] It is highly sensitive in differentiating keratoconus from normal eyes and highly specific for prekeratoconic corneas. It has been considered second to BAD-D in terms of accuracy in predicting KC. 4. Keratoconus index (KI) is the ratio between mean radius values in the upper half and lower half of cornea. KI >1.07 is abnormal.(11) KI is an efficient diagnostic test to discriminate normal eyes from clinical KC, thus a reliable parameter for screening but has limited application in pre-KC diagnosis. 5. Central keratoconus index (CKI) is the ratio between mean radius of curvature of a peripheral placido ring and mean radius of curvature of central ring. A CKI >1.03 is considered abnormal. It is a valuable tool for diagnosis of frank KC.[8] 6. Index of height asymmetry (IHA) is the mean difference between corneal elevation in superior hemisphere and inferior hemisphere in the horizontal meridian, expressed in microns. An IHA >19 is abnormal, and IHA >21 is pathological.[8] 7. Index of height decentration (IHD) measures vertical decentration of elevation data in microns calculated using Fourier analysis on a ring with a radius of 3 mm. IHD >0.014 is abnormal, and IHD >0.016 is pathological. It has the potential to discriminates pre-keratoconus cases.[8] 8. Rmin is the smallest radius of sagittal corneal curvature. It denotes the maximum steepness of the cone. Rmin <6.71 mm is abnormal.[6] Clinical Uses of Pentacam • Screening for corneal ectasia Early stages of keratoconus often look normal on slit lamp examination, and manual keratometry, which assesses the central 3 mm, may give an insufficient assessment. Because of this, topography has become the gold standard for screening patients for keratoconus and other corneal ectasias. Various criteria have been set to diagnose keratoconus or forme fruste keratoconus. (Figure-8) • Corneal ectasia monitoring and treatment Once an ectasia is diagnosed, topography may be useful for monitoring disease progression. This precise monitoring allows early intervention such as collagen cross-linking or keratoplasty. Topographic warning signs include high central corneal power, a large difference between the two corneas of a patient, and a large disparity between the refractive power at the apex and the periphery. • Refractive surgery screening and monitoring Surface ablative procedures such as photorefractive keratectomy (PRK) and laser assisted in situ keratomileusis (LASIK) use excimer laser to ablate tissue and reshape the cornea to correct refractive error. Screening should be done to determine corneal shape and patterns of astigmatism on topography before refractive surgery. Scheimpflug imaging can also be performed post-operatively to assess the etiology for unsatisfactory visual outcome such as decentred or incomplete ablations. Figure 8: Red flag signs for corneal ectasia on Pentacam maps. Role of Epithelial Mapping in Refractive Workup Epithelial mapping seems to be an important tool in a refractive surgeon’s armamentarium for differentiating suspicious from normal corneas and identifying those with true progression of corneal ectasia.[12] (Figure-9) • It helps in modifying the type of refractive surgery based on epithelial regularity and thickness to provide the most optimal outcomes. • It allows the refractive surgeon to differentiate true regression from pseudo-regression in patients who have undergone refractive surgery and aids in planning subsequent management. • It helps to unmask any epithelial irregularities, which may Corneal Diagnostics

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 26 Role of CorVis ST in Refractive Workup Corneal Visualization Scheimpflug Technology (CorVis ST) (Oculus Optikgeräte GmbH, Wetzlar, Germany) is a recently developed noncontact tonometry system since 2011. With an integrated ultra-high-speed Scheimpflug Camera, it can record real-time dynamic deformation of the cornea, allowing direct description of the corneal biomechanics for clinical evaluation. Corneal biomechanical changes have been mentioned as an effective factor in keratoconus formation, and it might be detectable before the tomographic and clinical signs of keratoconus become apparent. (Figure-10) At present, there are two clinically available equipments which have made measuring biomechanical properties of cornea in vivo possible: Ocular Response Analyzer (ORA) and CorVis ST. Corvis ST be the cause for blurred vision post-refractive surgery. • Comparative epithelial, stromal, and posterior elevation maps on MS 39 can aid in differentiating true-progression from pseudo-progression in keratoconus especially in cases where the Pentacam comparative map shows an obvious progression. • Epithelial irregularities are also commonly seen in contact lens wearers who often show signs of corneal warpage in the form of arcuate lesions. This may lead to anterior surface topography changes and variable refraction. Figure 9: Pachymetric map of RTVue® (Optovue Inc, Fremont, CA) showing inferotemporal thinning in the right eye, along with the corresponding thinning of the overlying epithelium in cone area. captures a series of horizontal Scheimpflug images using a highspeed camera that gathers 4,300 frames per sec within a 100 milliseconds (ms) period. Case Examples Case 1 (Figure-12): A patient with forme fruste keratoconus in right eye and grade 1 keratoconus (Amsler-Krumeich classification) in left eye. Cornea based refractive procedure is contraindicated in such case. Case 2 (Figure-13): A patient with pellucid marginal corneal degeneration in both eyes. Pentacam quad map reveals crab claw or kissing dove pattern on sagittal curvature map. Cornea based refractive procedure is contraindicated in such case. Corneal Diagnostics

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 27 Figure 10: Biomechanical/topographic assessments (ARV) of CorVis ST showing Corvis Biomechanical Index (CBI), Belin/Ambrósio Enhanced Ectasia Deviation Index (BAD-D), and Tomographic and Biomechanical Index (TBI) within normal (green) range. Figure 11: Pentacam map of a patient with forme fruste keratoconus in right eye and grade 1 keratoconus (Amsler-Krumeich classification) in left eye showing an asymmetric bow tie pattern (inferior steepening) on the axial curvature map with corresponding corneal thinning and increased anterior and posterior elevation at the location of maximum steepening. Belin-ambrosio enhanced ectasia display map of the same patient showing hot colours in the elevation and difference map along with abnormal PPI, ARTmax, CTSP, PTI profile and D value. Corneal Diagnostics

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 28 Figure 12: Pentacam map of a patient with pellucid marginal corneal degeneration in both eyes showing crab claw or kissing dove pattern on sagittal curvature map. The area of maximum curvature and thinning are not corresponding. Belin-ambrosio enhanced ectasia display map of the same patient showing hot colours in the elevation and difference map along with abnormal PPI, ARTmax, CTSP, PTI profile and D value. References 1. Mazen Sinjab. Reading Pentacam Topography (Basics and Case Study Series). 2nd ed. JAYPEE; 6,9-11,20-48. 2. Randleman JB, Woodward M, Lynn MJ, Stulting RD. Risk assessment for ectasia after corneal refractive surgery. Ophthalmology. 2008 Jan;115(1):37–50. 3. Jain R, Grewal S. Pentacam: Principle and Clinical Applications. Dada T, Singh K, Spaeth GL, editors. Curr J Glaucoma Pract DVD. 2009 May;20–32. 4. Ambrósio R, Alonso RS, Luz A, Coca Velarde LG. Corneal-thickness spatial profile and corneal-volume distribution: tomographic indices to detect keratoconus. J Cataract Refract Surg. 2006 Nov;32(11):1851– 9. 5. Villavicencio OF, Gilani F, Henriquez MA, Izquierdo L, Jr, Ambrósio RR, Jr, Belin MW. Independent population validation of the Belin/ Ambrósio enhanced ectasia display: Implications for keratoconus studies and screening. Int J Kerat Ect Cor Dis. 2014;3:1–8. 6. Kanellopoulos AJ, Asimellis G. Revisiting keratoconus diagnosis and progression classification based on evaluation of corneal asymmetry indices, derived from Scheimpflug imaging in keratoconic and suspect cases. Clin Ophthalmol. 2013;7:1539–48. 7. Wahba SS, Roshdy MM, Elkitkat RS, Naguib KM. Rotating Scheimpflug imaging indices in different grades of keratoconus? J Ophthalmol. 2016;2016:6392472. 8. Motlagh MN, Moshirfar M, Murri MS, Skanchy DF, Momeni-Moghaddam H, Ronquillo YC, et al. Pentacam® corneal tomography for screening of refractive surgery candidates: A review of the literature, Part I. Med Hypothesis Discov Innov Ophthalmol. 2019;8:177–203. 9. Bae GH, Kim JR, Kim CH, Lim DH, Chung ES, Chung TY. Corneal topographic and tomographic analysis of fellow eyes in unilateral keratoconus patients using Pentacam. Am J Ophthalmol. 2014;157:103– 9e1. 10. Ruiseñor Vázquez PR, Galletti JD, Minguez N, Delrivo M, Fuentes Bonthoux F, Pförtner T, et al. Pentacam Scheimpflug tomography findings in topographically normal patients and subclinical keratocoCorneal Diagnostics

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 29 nus cases. Am J Ophthalmol. 2014;158:32–40e2. 11. Ambrósio R, Faria-Correia F, Ramos I, Valbon BF, Lopes B, Jardim D, et al. Enhanced screening for ectasia susceptibility among refractive candidates: The role of corneal tomography and biomechanics. Curr Ophthalmol Rep. 2013;1:28–38. 12. Khamar P, Rao K, Wadia K, Dalal R, Grover T, Versaci F, Gupta K. Advanced epithelial mapping for refractive surgery. Indian J Ophthalmol. 2020 Dec;68(12):2819-2830. Prof. Rajesh Sinha, MD, DNB, FIACLE, FRCS Cornea, Lens and Refractive Surgery Services Dr Rajendra Prasad Centre for Ophthalmic Science, AIIMS New Delhi. Corresponding Author: Corneal Diagnostics

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 30 Fungal Keratitis Pallavi Sugandhi, MS, FMRF Cornea & Refractive Surgeon, Complete Eye Care Centre, Mayur Vihar, Delhi. Fungal keratitis is an important cause of corneal morbidity. The early stage of fungal keratitis remains a diagnostic and therapeutic challenge to the ophthalmologist. There is difficulty in establishing the clinical diagnosis, isolating the etiologic fungal organism in the laboratory, and treating the keratitis effectively with topical antifungal agents. Unfortunately, delayed diagnosis is common due to of lack of suspicion. When a diagnosis has been made, management remains a challenge because of the poor corneal penetration of antifungal agents. Incidence The incidence of fungal keratitis has increased over the past 30 Aspergillus species is the most common isolate in fungal keratitis worldwide.[3,4] Satpathy et al[3] in a large series from India reported that, the most common fungi isolated included Aspergillus spp. (31.1%), followed by Fusarium spp. (24.5%), Alternaria (10.5%), Curvularia (10.2%), Helminthosporium (5.7%), Bipolaris (5.4%), Penicillium (4.5%), Candida (4.4%), Acremonium (1.2%), Rhizopus (1.0%), Paecilomyces (0.8%), Rhodotorula (0.5%) and Mucor (0.2%). Commonest dematiaceous fungus years, it varies from 22% to 50% in developing world[1]. Higher incidence of fungal keratitis is a result of the frequent use of topical corticosteroids in younger age group specially in cases of vernal keratoconjunctivitis or agricultural occupations. Other risk factors to consider are vegetative foreign bodies, and immunosuppressive diseases like HIV. Uncontrolled diabetes is also an important risk factor in elderly patients along with history of trauma with vegetative matter.[2] Classification Among various fungi that have been implicated in fungal keratitis, the two medically important groups responsible for corneal infection are yeast and filamentous fungi. Chytridiomycota Zygomycota Ascomycota Basidiomycota Chytrids Bread mold, Rhizopus, mucor. Yeast, Sack fungi Aptamer Aseptate Septate 1 Phycomycetes Ascomycetes- Penicillium, aspergillus, fusarium 2 Zygomycetes- Rhizopus, mucor Basidiomycetes Molds-Deutromycetes, Alternaria, Tricoderma. Yeast- Pseudo hyphae e.g., Candida Classification of Fungi Classification on basis of septate and aseptate hyphae isolated are - Curvularia (44%), Phialophora (16%), Alternaria (12%).[4] Clinical Features Fungal organisms can extend from the cornea into the sclera and intraocular structures. Fungi can cause severe infections, such as scleritis, endophthalmitis, or panophthalmitis. Presenting clinical features (Figure-1 a, b, c, d) may include Figure 1: Clinical features (a, b,c,d) Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 31 • Fine or coarse granular infiltrate within the epithelium and anterior stroma • Gray-white colour, dry, and rough corneal surface that may appear elevated • Typical irregular feathery-edged infiltrate • White Immune ring in the cornea and satellite lesions near the edge of the primary focus of the infection • In advanced cases, suppurative stromal keratitis associated with anterior chamber inflammation, hypopyon, iritis, endothelial plaque, or possible corneal perforation Immune rings may also be present in infections with other pathogens such as acanthamoeba, pseudomonas and even stromal viral keratitis. Microbiological examination is therefore of utmost importance. Dematiaceous fungi (Figure-2) are characterized by the development of a brown, olive or black colour in the cell walls of their vegetative cells, conidia or both which results in pigment colonies on culture. Clinically small proportion of cases showed brown to black macroscopic pigmentation (24%). Pigmentation of fungal filaments related to melanin metabolism, linked to altered metabolic state associated with low virulence and less severe inflammation. Classical macroscopic pigmentation may not always be the presenting feature. Figure 2: Dematiaceous Fungi Pythium Insidiosum is a parasitic aquatic oomycete.[5] It causes a relatively rare form of keratitis. But can cause blinding manifestations. It is also classified as pseudofungus or parafungus and is frequently misdiagnosed as fungal keratitis. Clinical features include raised dot like infiltrates (Figure-3) greyish-white infiltrate with tentacle-like lesions. Peripheral furrowing may also be present. It appears as slender long ribbon like hyphae with perpendicular lateral branches and numerous vesicles on 10% KOH. It can also be diagnosed on Iodine potassium iodide sulphuric acid staining and Gomori methamine silver staining. Antibacterial drugs like Linezolid (0.2%) and 1% Azithromycin are the drug of choice. Early full thickness corneal transplant should be considered for non-responding infections. Figure 3: Pythium Investigations Among The most important step in the initial management of suspected fungal keratitis is to obtain corneal material for direct smears and inoculation of media. Smears are used to obtain rapid information about the pathogen. KOH smears easily identify the fungal hyphae and the treatment can be instituted on the basis of these smears. Gram stain identifies yeast, and Giemsa stain is also useful in detecting fungal elements. The primary isolation cultures for fungus are Sabouraud dextrose and blood agar at room temperature. Yeast produces characteristic creamy, opaque, pasty colonies on the surface of culture media. Candida is the most representative pathogen in this group, primarily affecting those corneas already compromised by topical steroids, surface pathology, or both. A feathery or powdery growth on the surface of culture media is produced by septate filamentary fungi, which are the most common cause of fungal keratitis. Antifungal susceptibility testing to establish the sensitivity to treatment with conventional and newer antifungal agents can also be undertaken. Recently, molecular diagnostic methods like polymerase chain reaction are gaining popularity as they allow accurate and rapid diagnosis. In vivo scanning slit confocal microscopy identifies the fungal hyphae. Newer modalities like metagenomic deep sequencing (MDS), which involves both DNA and RNA sequencing has been suggested to have potential for improved diagnostic sensitivity and accuracy.[6,7] Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a reliable technique which helps identify pathological organisms in minutes.[8] It has now been extended to identify isolates of fungi, particularly yeasts, and also a few filamentous fungi, including Aspergillus, Penicillium, Fusarium, and Mucorales apart from bacterial pathogens for which it was used earlier. These methods may be used wherever available. Medical Management Antifungal agents are mainstay of treatment (Figure-4) and are classified into the groups below. Corneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 32 A) POLYENES Polyenes include natamycin, nystatin, and amphotericin B. Polyenes disrupt the cell by binding to fungal cell wall ergosterol and are effective against both filamentous and yeast forms. Although polyenes penetrate ocular tissue poorly, amphotericin B is the drug of choice for treatment of fungal keratitis caused by Candida. In addition, it has efficacy against many filamentous fungi (Fusarium). It may be used as topical, intrastromal, or intracameral preparation but surface toxicity is a major issue.[9,10] It is available as 50mg powder which is reconstituted in 10 ml of sterile water. 3ml of this reconstituted solution is then made into 10ml by adding 7ml sterile water to make it into concentration of 0.15% and dispensed in a dark brown bottle. Administration is every 30 minutes for the first 24 hours, every hour for the second 24 hours, and then is continued every 2 hourly according to the clinical response. Drops are clear yellow in colour, if they turn milky then it should be discarded. Usually, the prepared solution can be used for a week. Natamycin has a broad-spectrum of activity against filamentous organisms. Natamycin is the only commercially available topical ophthalmic antifungal preparation. It is effective against filamentous fungi, particularly for infections caused by Fusarium. However, because of poor ocular penetration, it has primarily been useful in cases with superficial corneal infection.[9,12] B) AZOLES Azoles (imidazoles and triazoles) include ketoconazole, miconazole, fluconazole, itraconazole and clotrimazole. Azoles inhibit ergosterol synthesis at low concentrations, and, at higher concentrations, they appear to cause direct damage to cell walls. Voriconazole is a newer synthetic azole having good efficacy against filamentous fungi. Recent reports have shown that it may not be effective against Fusarium but shows good activity against aspergillus.[10,11] It is commercially available as 30 mg powder and can be reconstituted with 3 ml of sterile water to form 1% solution. The largest randomized control trial, the MUTT-1 trial[12], comparing topical 1% voriconazole and natamycin 5%, failed Figure 4: Anti-fungal- Mechanism of action Figure 5: A case of fungal abscess (RK done 20 yrs. back), S/P intrastromal voriconazole injections to demonstrate its benefit over conventional, FDA-approved natamycin drops. However, with the available literature[15,16,19], voriconazole seems to be the alternative drug for recalcitrant cases not responding to natamycin and amphotericin B and also as an adjunctive in severe fungal keratitis. Intrastromal, intracameral and intravitreal use of antifungal agents has been found useful in the treatment of recalcitrant keratitis[15,18], fungal keratitis in deep stromal/endothelial infections or with associated endophthalmitis[16,20] and also for post keratoplasty, kerato-refractive surgery (Figure-5) and mycotic keratitis. Also,even though the randomized control trial[13] evaluating the role of intrastromal voriconazole application in fungal keratitis failed to demonstrate any benefit, voriconazole is the most commonly used intrastromal antifungal agent with many authors.[16,17,18] The commonly used agents are voriconazole at a dose of 50–100 µg/0.1 mL and amphotericin B at a dose of 5–7.5 µg/0.1 mL. Systemic Therapy Oral Voriconazole, fluconazole and ketoconazole are absorbed systemically with good levels in the anterior chamber and the cornea; therefore, an oral antifungal should be considered for patients with deep stromal infections, scleral involvement or endophthalmitis.[13,14] Antifungal therapy usually is maintained for 12 weeks, and patients are monitored closely with regular LFT, KFT levels. The adult dose of ketoconazole is 200-400 mg/d, which can be increased to 800 mg/d. However, because of the secondary effects, increasing the dose should be decided carefully. Gynecomastia, oligospermia, and decreased libido have been reported Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 33 in 5-15% of patients who have been taking 400 mg/d for a long period. The MUTT-2 trial[13], the only randomized control trial done to evaluate the efficacy of oral antifungal (voriconazole) as an adjuvant treatment to topical medication in severe filamentous fungal keratitis found no added benefit. However, a secondary sub-analysis from the MUTT-2 trial[19] showed a possible advantage of adding oral voriconazole to culture positive fusarium keratitis with reduced rate of perforation (but not statistically significant), a decreased the need for TPK, reduced scar size and better visual acuity at three months. Systemic antifungals, as an adjunct treatment to topical agents, are indicated in ulcers >5 mm in size, with involvement of >50% stromal depth, recalcitrant infections, bilateral infections, when associated with scleritis, with limbal involvement or endophthalmitis, paediatric cases, post keratoplasty infections and in cases of impending perforation/perforated ulcers.[13,14,16,17] Voriconazole may be prescribed in dosage of 200mg twice daily for a mean of 10weeks depending on severity. It has higher bioavailability but has side effects like hallucinations, colour vision disturbances and increased sensitivity to light.[21] The potential role of topical itraconazole in treatment of fungal keratitis is still unclear. However, it may be a helpful adjunctive agent in fungal keratitis. Luliconazole and Posaconazole are newer drugs which need experimental and clinical evaluation as a treatment option in a topical formulation due to a need for a better antifungal drug with a lower MIC specially against Fusarium species.[17] C) PYRIMIDINES Fluorinated pyrimidines, such as flucytosine, are other antifungal agents. Flucytosine is converted into a thymidine analog that blocks fungal thymidine synthesis. It usually is administered in combination with an azole or amphotericin B; it is synergistic with these medications. Otherwise, if flucytosine is the only drug used in therapy for candidal infections, emergence of resistance rapidly develops. Therefore, flucytosine should never be used alone. Newer Modified Drug Formulations and Drug Delivery Systems have been under development for Better corneal penetration, superior pharmacokinetics and biodistribution while minimizing toxicity. Liposomal formulations of drugs have been tried for Amphotericin B, voriconazole and itraconazole. Drug-loaded polymeric micelles and nanoparticles are underway for Nano formulation of natamycin. Polyethylene glycol-based formulation of ketoconazole and Amphotericin-B entrapped lecithin/chitosan nanoparticles are also under trial.[22,23] Surgical Intervention Patients not responding to medical treatment of topical and oral antifungal medications usually require surgical intervention, including corneal transplantation. Approximately 50% of patients require surgical intervention in terms of penetrating or deep lamellar keratoplasty.[17] The common indications for TPK in a case of fungal keratitis include perforated ulcers, impending perforations and recalcitrant keratitis worsening on conservative management. Prajna et al.[19], in a secondary analysis with the MUTT-2 data, evaluated the predictors that could potentially indicate the need for a TPK in fungal keratitis. The presence of hypopyon along with increasing infiltrate size and more than 75%depth were noted to have a significant association with the need for TPK. The survival of a corneal graft in an actively infected and inflamed eye is very minimal with an increased chance of graft rejection, re-infection and secondary glaucoma. The rates of re-infection after keratoplasty procedures are a major concern in fungal keratitis with rates ranging from 6% to 16%.[17,19] Lamellar keratoplasty (LK) in managing fungal keratitis is gaining popularity due to the advantages of a lamellar procedure over a full-thickness procedure and is being performed in selective cases. Xie et al[24] in their study comprising 55 fungal keratitis cases refractory to conventional treatments, LK gave a success rate of 92.7% (n = 51) with a recurrence rate of just 7.3% (n = 4) and good visual and anatomical outcomes after 12–18 months of follow-up. Various other studies[25] have also concluded early surgical intervention in the form of deep anterior lamellar keratoplasty (DALK) can be a safe therapeutic approach in the management of fungal keratitis. Anti-fungals should be continued at least 6 weeks post operatively and weak steroids such as fluorometholone should be started after 2 weeks only when there are no signs of infection. A small perforation or a descematocele can be managed by tissue adhesive and BCL if the ulcer is in healing stage. Collagen crosslinking in active fungal ulcers is of limited value. It can be used as an adjuvant for conventional treatment in resistant cases with photoactivated riboflavin (PACK CXL) for the treatment of advanced infectious keratitis with corneal melting. In 2000, Schnitzler[26] first described the use of CXL to four patients suffering from melting ulcer of the cornea of various origins. Because PACK-CXL increases tissue resistance to enzymatic digestion, the cross-linking procedure may help the corneal stroma resist proteolysis by enzymes from polymorphonuclear leukocytes participating in the inflammatory process. A fortified stroma also may block the penetration or effect of toxins from the pathogenic organism. The phenomenon of apoptosis induced by PACK-CXL likely not only kills keratocytes but also kills microbes, which decelerates the infectious process.[27,28] In another study by Uddaraju etal,[29] the authors enrolled patients of deep keratomycosis that did not respond to 2 weeks of medical treatment and randomized into collagen cross linking or no additional treatment. The study found that the collagen cross linking does not offer any advantage over standard medical treatment. In deep kerato-mycosis,it was associated with increased risk of corneal perforation. The role of corneal crosslinking in the management of mycotic keratitis remains controversial in humans with different studies providing conflicting results. Some case However, the CrossCorneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 34 Linking Assisted Infection Reduction Trial (CLAIR trial), a randomised control trial[30] done to evaluate the role of corneal collagen crosslinking in the management of fungal keratitis concluded that it has no added advantage and furthermore suggested that crosslinking can result in inferior visual outcomes when compared with standard medical management in fungal keratitis. Argon laser irradiation of the affected cornea has been tried and performed using argon blue-green wavelength (Coherent Ultima 2000; Coherent, Inc). A spot size of 500-micron, pulse duration of 0.10 seconds, and power ranging from 500 to 900mW. During the first week after laser treatment, both patients showed complete resolution of the infiltrates. Two signs were observed during the procedure: a blanching of the corneal stroma and small cavitations that reached the middle stroma. There were no adverse reactions but further studies are needed to evaluate the procedure.[31] To conclude, Fungal keratitis still remains a challenge for the treating ophthalmologist. Hence, early diagnosis coupled with appropriate aggressive treatment is critical to recovery. Inspite of maximum medical or surgical therapy, many patients may have recurrence or will have vision loss secondary to scar. Early therapeutic keratoplasty/DALK may be considered for better visual outcome. Newer antifungal agents and combination therapy in comparison to monotherapy are seen to be more efficacious in the management of mycotic keratitis. Future strategies to reduce morbidity due to mycotic keratitis with adjuvant therapies should be aimed at better drug penetration and higher sensitivity to improve clinical outcomes. References 1. Shah A, Sachdev A, Coggon D, Hossain P. Geographic variations in microbial keratitis: an analysis of the peer-reviewed literature. Br J Ophthalmol 2011; 95:762–767. 2. Vemuganti GK, Garg P, Gopinathan U et al. Evaluation of agent and host factors in progression of mycotic keratitis: A histologic and microbiologic study of 167 corneal buttons. Ophthalmology 2002; 109: 1538–1546. 3. Satpathy G., Ahmed N.H., Nayak N., Tandon R., Sharma N., Agarwal T., Vanathi M., Titiyal J.S. Spectrum of mycotic keratitis in north India: Sixteen years study from a tertiary care ophthalmic centre. J. Infect. Public Health. 2019; 12:367–371. 4. Bharathi M.J., Ramakrishnan R., Meenakshi R., Padmavathy S., Shivakumar C., Srinivasan M. Microbial keratitis in South India: Influence of risk factors, climate, and geographical variation. Ophthalmic Epidemiol. 2007; 14:61–69. 5. New Insights into the In Vitro Susceptibility of Pythium insidiosum. Érico S. Loreto, a Juliana S. M. Tondolo, a Maiara B. Pilotto, a Sydney H. Alves, b Janio M. Santurioa. Antimicrobial Agents and Chemotherapy p. 7534 –7537 December 2014 Volume 58 Number 12. 6. Seitzman G.D., Hinterwirth A., Zhong L., Cummings S., Chen C., Driver T.H., Lee M.D., Doan T. Metagenomic Deep Sequencing for the Diagnosis of Corneal and External Disease Infections. Ophthalmology. 2019; 126:1724–1726. 7. Lalitha P., Prajna N.V., Sikha M., Gunasekaran R., Hinterwirth A., Worden L., Chen C., Zhong L., Liu Z., Lietman T.M., et al. Evaluation of Metagenomic Deep Sequencing as a Diagnostic Test for Infectious Keratitis. Ophthalmology. 2021; 128:473–475. 8. Patel R. A Moldy Application of MALDI: MALDI-ToF Mass Spectrometry for Fungal Identification. J. Fungi. 2019; 5:4. 9. Sharma S, Das S, Virdi A, et al. Re-appraisal of topical 1% voriconazole and 5% natamycin in the treatment of fungal keratitis in a randomised trial. Br J Ophthalmol 2015; 99:1190–1195. 10. Sharma N, Chacko J, Velpandian T, et al. Comparative evaluation of topical versus intrastromal voriconazole as an adjunct to natamycin in fungal keratitis. Ophthalmology 2013; 120:677–681. 11. Kalaiselvi G, Narayana S, Krishnan T, Sengupta S. Intrastromal voriconazole for deep recalcitrant fungal keratitis: a case series. Br J Ophthalmol 2015; 99:195–198. 12. Prajna N.V., Krishnan T., Mascarenhas J., Rajaraman R., Prajna L., Srinivasan M., Raghavan A., Oldenburg C.E., Ray K.J., Zegans M.E., et al. The mycotic ulcer treatment trial: A randomized trial comparing natamycin vs. voriconazole. JAMA Ophthalmol. 2013; 131:422–429. 13. Prajna N.V., Krishnan T., Rajaraman R., Patel S., Srinivasan M., Das M., Ray K.J., O’Brien K.S., Oldenburg C.E., McLeod S.D., et al. Effect of Oral Voriconazole on Fungal Keratitis in the Mycotic Ulcer Treatment Trial II (MUTT II): A Randomized Clinical Trial. JAMA Ophthalmol. 2016; 134:1365–1372. 14. Prajna N.V., Krishnan T., Rajaraman R., Patel S., Shah R., Srinivasan M., Devi L., Das M., Ray K.J., O’Brien K.S., et al. Adjunctive Oral Voriconazole Treatment of Fusarium Keratitis. JAMA Ophthalmol. 2017; 135:520–525. 15. Maharana P.K., Sharma N., Nagpal R., Jhanji V., Das S., Vajpayee R.B. Recent advances in diagnosis and management of Mycotic Keratitis. Indian J. Ophthalmol. 2016; 64:346–35. 16. Sharma N., Sahay P., Maharana P.K., Singhal D., Saluja G., Bandivadekar P., Chako J., Agarwal T., Sinha R., Titiyal J.S., et al. Management Algorithm for Fungal Keratitis: The TST (Topical, Systemic, and Targeted Therapy) Protocol. Cornea. 2019; 38:141–145. 17. Raj N, Vanathi M, Ahmed NH, Gupta N, Lomi N, Tandon R. Recent Perspectives in the Management of Fungal Keratitis. J Fungi (Basel). 2021 Oct 26;7(11):907. 18. Saluja G., Sharma N., Agarwal R., Sharma H.P., Singhal D., Kumar Maharana P., Sinha R., Agarwal T., Velpandian T., Titiyal J.S., et al. Comparison of Safety and Efficacy of Intrastromal Injections of Voriconazole, Amphotericin B and Natamycin in Cases of Recalcitrant Fungal Keratitis: A Randomized Controlled Trial. Clin. Ophthalmol. 2021; 15:2437–2446. 19. Prajna N.V., Krishnan T., Rajaraman R., Patel S., Shah R., Srinivasan M., Das M., Ray K.J., Oldenburg C.E., McLeod S.D., et al. Predictors of Corneal Perforation or Need for Therapeutic Keratoplasty in Severe Fungal Keratitis: A Secondary Analysis of the Mycotic Ulcer Treatment Trial II. JAMA Ophthalmol. 2017; 135:987–991. 20. Narayana S., Krishnan T., Ramakrishnan S., Samantaray P.P., Austin A., Pickel J., Porco T., Lietman T., Rose-Nussbaumer J. Mycotic Antimicrobial Localized Injection (MALIN): A Randomized Clinical Trial Evaluating Intrastromal Injection of Voriconazole. Ophthalmology. 2019; 126:1084–1089. 21. Sahay P., Singhal D., Nagpal R., Maharana P.K., Farid M., Gelman R., Sinha R., Agarwal T., Titiyal J.S., Sharma N. Pharmacologic therapy of mycotic keratitis. Surv. Ophthalmol. 2019; 64:380–400. 22. Jain A, Shah SG, Chugh A. Cell penetrating peptides as efficient nanoCorneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 35 carriers for delivery of antifungal compound, natamycin for the treatment of fungal keratitis. Pharm Res 2015; 32:1920–1930. 23. Ghosh A.K., Rudramurthy S.M., Gupta A., Choudhary H., Singh S., Thakur A., Jatana M. Evaluation of Liposomal and Conventional Amphotericin B in Experimental Fungal Keratitis Rabbit Model. Transl. Vis. Sci. Technol. 2019; 8:35. doi: 10.1167/tvst.8.3.35. 24. Xie L., Shi W., Liu Z., Li S. Lamellar keratoplasty for the treatment of fungal keratitis. Cornea. 2002; 21:33–37. 25. Sabatino F., Sarnicola E., Sarnicola C., Tosi G.M., Perri P., Sarnicola V. Early deep anterior lamellar keratoplasty for fungal keratitis poorly responsive to medical treatment. Eye. 2017; 31:1639–1646. 26. Schnitzler E., Spörl E., Seiler T. Irradiation of cornea with ultraviolet light and riboflavin administration as a new treatment for erosive corneal processes, preliminary results in four patients. Klin. Mon. Augenheilkd. 2000; 217:190–193. 27. Advanced Infectious Keratitis with Corneal Melting Dalia G. Said,Ehab S. El-Zakzouk, Mansour A. Hassan, Mohamed Y. Saif, MD,3 Ahmed A. Zaki,Harminder S. Dua, Farhad Hafezi,Mohamed S. Elalfy. Ophthalmology Volume 121, Number 7, July 2014. 28. Vajpayee RB, Shafi SN, Maharana PK, et al. Evaluation of corneal collagen cross-linking as an additional therapy in mycotic keratitis. Clin Experiment Ophthalmol 2015; 43:103–107. 29. Uddaraju M, Mascarenhas J, Das MR, et al. Corneal cross-linking as an adjuvant therapy in the management of recalcitrant deep stromal fungal keratitis: a randomized trial. Am J Ophthalmol 2015; 160:131–134. 30. Prajna N.V., Radhakrishnan N., Lalitha P., Austin A., Ray K.J., Keenan J.D., Porco T.C., Lietman T.M., Rose-Nussbaumer J. Cross-Linking– Assisted Infection Reduction. Ophthalmology. 2020;127:159–166. 31. Argon Laser Phototherapy in the Treatment of Refractory Fungal Keratitis. Fernando Pellegrino, MD* and María Alejandra Carrasco, MD† Cornea Volume 32, Number 1, January 2013. 95. Dr. Pallavi Sugandhi , MS, FMRF Cornea & Refractive Surgeon Complete Eye Care Centre, Mayur Vihar Phase-2, Delhi. Corresponding Author: Corneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 36 Viral Keratitis Sohini Mandal, MD, FAICO, Siddhartha Rao B.S., MBBS, Muskan Garg, MBBS, Prafulla K. Maharana, MD Cornea, Cataract and Refractive services, Dept. of Ophthalmology, Dr.R P Centre for Ophthalmic Sciences, AIIMS, New Delhi. Introduction Herpes keratitis includes two distinct diseases – herpes simplex keratitis (HSK) and herpes zoster keratitis (HZK). HSV infections of the eye are the leading cause of infectious corneal blindness in developed countries.[1] While most infections are unilateral, around 1.3%–12% of affected individuals have bilateral ocular infections. Bilateral infections are seen mostly in immunocompromised patients.[2] Primary infection results after HSV spread via direct contact with mucous membrane of the host. HSV is transported by primary retrograde infection via sensory neurons to establish latency in trigeminal ganglia; here, it remains asymptomatic until reactivation of the virus leading to recurrent infections. Diagnosis The diagnosis of viral keratitis is primarily made based on clinical examination in contrast to bacterial or fungal keratitis. It is dependent predominantly on a thorough slit lamp examination and confirmatory laboratory testing. Following are the indications for laboratory testing: a) Atypical presentation b) Necrotising stromal keratitis c) Recurrent disease d) Not responding to conventional treatment Clinical Diagnosis Diagnostic Clue Clinical Diagnosis Dendritiform lesion Epithelial viral keratitis Peripheral ulcerative keratitis with scalloped margins and no lucid interval Marginal viral keratitis Persistent epithelial defect oval in shape with rolled margins Neurotrophic keratitis Stromal edema with Descemet membrane (DM) folds Immune mediated stromal keratitis Dense stromal infiltrate with ulceration and necrosis Necrotising stromal keratitis Stromal edema with underlying keratic precipitates Stromal kerato-uveitis Keratic precipitates with anterior chamber reaction and overlying DM folds Viral endothelitis Table-1 categorizes various types of HSV keratitis based on their primary anatomic and pathophysiologic etiologic characteristics. Common symptoms include redness, watery discharge, irritation, pain, and photophobia. The most common subtype, epithelial keratitis, appears as coarse granular spots that form punctuate lesions to start with and rapidly coalesce to form dendritic lesions and geographic/amoeboid ulcers on inadvertent usage of topical corticosteroids. The dendritic lesion with terminal bulbs has swollen borders with intraepithelial cell infiltration. Lesions are better visualized by staining with either fluorescein or rose bengal dye. Fluorescein dye stains the base of the ulcer whereas rose Bengal dye stains its edges. Immune mediated stromal keratitis appears opaque with ground glass appearance, due to stromal infiltration with no necrosis or ulceration. Similarly, the necrotizing form of stromal keratitis appears as gray-white or opaque, but there is accompanying necrosis and ulceration on slit-lamp examination. Lastly, the endothelial form, keratic precipitates, and iritis may be visible with overlying stromal edema. KPs with coin shapes are an analogous reference for CMV endotheliitis or VZV/EBV stromal keratitis in rarer cases. However, atypical lesions can make diagnosis difficult. Factors such as duration of illness, systemic disease, previous medication use, and corneal transplantation, can change the appearances of lesions. Confirmatory Laboratory Testing: Sample Collection Methods: Corneal samples can be obtained using a swab, spatula, scalpel, or a spud. PCR assays require corneal scrapings. Alternatively, viral load can be determined from patient tears. Satpathy et al compared viruses collected by this less invasive technique with that collected by corneal scraping using immunofluorescence assay, PCR, and viral titres.[3] While PCR of virus collected from tears is more sensitive than both viral isolation and immunofluorescence from tears, it is significantly less sensitive than corneal scraping. Methods of Laboratory Testing: Enzyme-linked immunosorbent assay (ELISA) and viral cultures have been used as diagnostic tools for all subgroups of lesions. The sensitivity of ELISA is 49.2% and specificity is 82.6%. On the other hand, sensitivity and specificity for PCR is noted to be higher at 55.8% and 100%, respectively, in tears collected.[4,5] a) Polymerase Chain Reaction (PCR): The sensitivity of PCR declines later during infection. Hence, a negative test does not necessarily mean absence of virus. PCR is more likely to identify patients that present with typical lesions or patients who are not on antiviral medications. It is less likely Table 1: Clinical diagnosis based on pathognomonic features on slit lamp examination Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 37 to identify patients with atypical lesions or who previously used or currently use antiviral medications.[5] Rose Bengal and lissamine green dye inhibit the detection of HSV DNA by PCR assay.[6] b) Enzyme Linked Immunosorbent Assay (ELISA): Aqueous humor can also be analysed for the presence of antibodies using ELISA, and the Goldmann-Witmer coefficient (GWC) can be calculated. A GWC > 3 is considered positive for antibody production. PCR and GWC assays complement each other as diagnostic tools. Misdiagnosis in clinical settings is common, as amoebic and fungal infections can mimic in clinical presentation.[7] c) Viral Culture: This is considered the gold standard for identifying HSV. When compared to viral culture, clinical diagnosis is only 55%–65% accurate. Unfortunately, culturing HSV is time-consuming and can take a week or longer when few infectious viruses are in the sample. d) Immunofluorescene Assay (IFA): Immunofluorescence tests are rarely used as their sensitivity is much lower than the other methods. It has a sensitivity of 80% and specificity of 71.4%.[3] Management HSV keratitis infections are often self-limiting however, healing is delayed without antiviral use, and inappropriate treatment can worsen inflammation leading to recurrence and subsequent deterioration in vision. Therefore, it is recommended to initiate treatment at the earliest, to reduce viral replication, shorten disease course, and maintain latency. Medical Management Current available first line antivirals for HSV keratitis are acyclovir, ganciclovir, triflurothymidine, penciclovir, and valacyclovir.[7,8] First Line Antivirals a) Acyclovir: Acyclovir and its derivatives are nucleoside analogs that are selectively phosphorylated by the virally encoded thymidine kinase. It does not cure infected cells of the virus, but it prevents new viruses from being produced as it affects only newly synthesized viral DNA. Owing to its poor bioavailability, high doses with increased frequency of administration are essential. b) Valacyclovir: Valacyclovir, another nucleoside analog, has relatively better bioavailability, and thus it has reduced frequency of administration resulting in better patient compliance. c) Ganciclovir: The mechanism of action of ganciclovir is similar to that of acyclovir. Though it has fewer gastrointestinal side effects, it can cause blurred vision and punctate keratitis. In immunocompromised hosts, long-term treatment with these antivirals has resulted in resistance, due to mutations in thymidine kinase or DNA polymerase. The commonly used antivirals have been enlisted in Table-2. Antiviral Agents Route of Administration Mechanism of Action Frequency Side Effects Acyclovir ointment 3% Topical Inhibits viral DNA polymerase 5 times/day (for 7 days) 3 times/day for another 7 days or till epithelial defect heals whichever is earlier Stinging Ganciclovir gel 0.15% Topical Inhibits viral DNA polymerase 5 times/day (for 7 days) 3 times/day for another 7 days or till epithelial defect heals whichever is earlier Less stinging, expensive Trifluridine drops 1% Topical Inhibits viral thymidylate synthase 2 hourly/day Superficial punctate keratitis, punctal occlusion, follicular conjunctivitis, dermatitis Vidarabine ointment 3% Topical Inhibits viral DNA polymerase 5 times/day Burning, itching Acyclovir Systemic Guanosine analogue 400 mg 5 times/day (Therapeutic); 400 mg 2 times/day (Prophylactic) Altered renal function, nausea Valacyclovir Systemic Guanosine analogue 1000 mg twice a day (Therapeutic) Nausea, vomiting Famciclovir Systemic Guanosine analogue 250 mg twice a day Nausea, vomiting Table 2: List of commonly used antivirals, their route of administration, mechanism of action, dosage and side effects Corneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 38 Antiviral Agents Route of Administration Mechanism of Action Frequency Side Effects Cidofovir Intravenous Competitive inhibitor and an alternate substrate for cytomegalovirus DNA polymerase 5 mg/kg/week every alternate week Nephrotoxic when taken orally Brincidofovir Intravenous Competitive inhibitor and an alternate substrate for cytomegalovirus DNA polymerase 5 mg/kg/week every alternate week Can be taken orally (lipid ester form of cidofovir) Diarrhoea in paediatric age group Table 3: List of second line antivirals, their route of administration, mechanism of action, dosage and side effects Second Line Antivirals They have less specificity for viral DNA and are more likely to have significant toxicity in patients. Example: Foscarnet and Cidofovir. The least commonly used antivirals are enlisted in Table-3. The Herpetic Eye Disease Study (HEDS) A randomized, double-masked, clinical trial was conducted by National Eye Institute (NEI) in 1989. The guidelines proposed by HEDS are still considered as gold standard for the treatment of anterior segment HSV disease. It was divided into three therapeutic, two preventive, and one cohort trials: The HEDS was conducted in two parts: HEDS-I, which started in May 1989 was divided into three clinical trials: • HEDS- SKN – Stromal Keratitis Not on Steroids To study the efficacy of topical steroids (prednisolone phosphate 1%) in treating HSV stromal keratitis in conjunction with topical antivirals (trifluridine). Topical corticosteroids significantly reduced the duration of stromal keratitis symptoms from 72 days to 26 days on average when compared to a placebo with faster resolution and fewer treatment failures. Delaying the initiation of the treatment with steroids did not affect the eventual outcome of the disease at 6 months post randomization. • HEDS-SKS – Stromal Keratitis on Steroids To study the efficacy of oral acyclovir 400mg 5 times/day in treating HSV stromal keratitis in patients receiving concomitant topical corticosteroids (prednisolone phosphate 1%) with topical antivirals (trifluridine). There was no additional benefit of oral acyclovir in preventing the development of HSK. • HEDS-IRT – Iridocyclitis Receiving Topical Steroids To study the efficacy of oral acyclovir 400mg 5 times/day in treating HSV iridocyclitis in conjunction with topical corticosteroids (prednisolone phosphate 1%) and topical antivirals (trifluridine). There was apparent benefit of oral Early generation drugs, such as idoxuridine, iododeoxyuridine, vidarabine, and trifluridine, are of historical importance due to their increased side-effect profile and low bioavailability. acyclovir in treating HSV iridocyclitis. Shortly after, the HEDS-II studies were conducted by NEI in 1992 that comprised of two randomised control trial arm and one epidemiological study arm. • HEDS- EKT – Epithelial Keratitis Trial This arm found that oral acyclovir, taken 400 mg at 5 times per day for three weeks, offered no additional benefits on top of topical trifluridine therapy in preventing the development of HSK. • HEDS-APT – Acyclovir Prevention Trial This arm found that a year of daily acyclovir administration reduced the relapse rates for ocular and orofacial HSV diseases. • HEDS-RFS – Recurrence Factor Study This arm was conducted to study the effect of psychological, environmental and biological factors (illnesses, injuries, sun exposure, UV light, menstrual cycles, emotional stress) on recurrences of herpetic eye disease. There are no statistically significant external or behavioural factors leading to recurrence.[9] These landmark studies have made prophylactic use of acyclovir and adjuvant corticosteroids to prevent episodes of HSK. As the number of episodes increases, corneal sensitivity to mechanical stimulation decreases. Subsequent episodes not only lead to corneal hypoesthesia, loss of blink reflex and dryness, but also corneal thinning, angiogenesis and neovascularization. As current treatment helps maintain latency and shortens the disease course, all infected patients are at risk of reactivation. Herpes Simplex Virus (HSV) 1. Epithelial viral keratitis: Algorithmic approach to a case of epithelial viral keratitis have been illustrated in Figure-1. Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 39 1.1. Infectious 1.1.a. Punctate: Topical preservative free lubricants, prophylactic broad-spectrum antibiotics (No role of topical antivirals) 1.1.b. Dendritic: Topical antivirals, preservative free lubricants, prophylactic broad-spectrum antibiotics, cycloplegic, Oral antivirals 1.1.c. Geographic: Topical antivirals, preservative free lubricants, prophylactic broad-spectrum antibiotics, cycloplegic, Oral antivirals 1.1.d. Marginal: Topical antivirals, corticosteroids, preservative free lubricants, prophylactic broad-spectrum antibiotics, cycloplegic, Oral antivirals 2. Stromal viral keratitis: Algorithmic approach to a case of stromal viral keratitis have been illustrated in Figure-2. 2.1.Immune Mediated: Topical corticosteroids, preservative free lubricants, prophylactic broad-spectrum antibiotics (if associated with overlying epithelial defect), cycloplegic, Oral antivirals 2.2.Necrotising: Topical preservative free lubricants, prophylactic broad-spectrum antibiotics, cycloplegic, Oral antivirals and corticosteroids 2.3.Non-Necrotising: Topical preservative free lubricants, broad spectrum antibiotics, bandage contact lens, multilayered amniotic membrane graft, tarsorrhaphy, mechanical debridement of the rolled edges of the ulcer, autologous serum, platelet rich plasma and IGF‐ 1 (optional). 3. Endothelial viral keratitis: Algorithmic approach to a case of endothelial viral keratitis have been illustrated in Figure-3. 3.1.Disciform: Topical corticosteroids, preservative free lubriCorneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 40 4. Herpetic Trabeculitis and Iridocyclitis: Topical corticosteroids, cycloplegic, anti-glaucoma, Oral antivirals and corticosteroids Herpes zoster ophthalmicus: Topical steroids, preservative free lubricants, prophylactic broad-spectrum antibiotics, anti-glaucoma, cycloplegics, Oral Acyclovir and pain killers (Amitriptylline), Capsaicin cream for zoster skin lesions Surgical Management Surgical management in the acute stage of herpes keratitis is seldom required except in necrotizing and severe neurotrophic ulcers, where there is progressive corneal necrosis despite optimal medical medications. 1. Corneal Gluing Tissue adhesives provide a tectonic support for impending and small corneal perforations. Cyanoacrylate tissue adhesives are composed of cyanoacrylic acid with alkyl side chains of various lengths. In contrast to cyanoacrylate (proinflammatory, uncomfortable, corneal vascularization) fibrin glue is flexible, biodegradable, and noninflammatory. Fibrin-based tissue adhesive assisted amniotic membrane transplant plug has been found to be efficacious in small corneal perforations however it has no significant bacteriostatic activity and is less effective at sealing corneal tissue defects compared to cyanoacrylate. Fibrin glue provides faster healing and induces less corneal neovascularization, at the cost of requiring a longer time to act. 2. Amniotic Membrane Transplantation (AMT) AMTs can both aid neurotrophic ulcers to heal and provide growth factors to promote migration of epithelial cells. Epitheliopathy with no significant stromal thinning respond well to a single-layered AMT approach. A multilayered approach is necessary for severe neurotrophic ulcer with stromal melt, where several layers of amniotic membrane tissue are stacked to fill the stromal defect covered by a larger overlay AMG. This not only provides a scaffold for epithelialization, but also provides structural support. 3. Tarsorrhaphy Tarsorrhaphy decreases ocular surface exposure, thereby reducing tear film evaporation, and providing a suitable environment for epithelial healing. The extent of lid closure can be altered based on the disease severity. Performing a temporary tarsorrhaphy at the time of keratoplasty promotes epithelialization of the graft. 4. Keratoplasty Keratoplasties are typically performed in HSV keratitis for tectonic support in cases of progressive ulceration, or for optical reason as in cases of scarring or lipid keratopathy. In such scenarios, they have favourably poor outcomes with 3-year survival rates of around 60%. There are multiple reasons such as: a) Presence of deep vascularization which increases the risk of rejection b) Recurrences of HSK are common after nerve regeneration in the graft c) Differentiating recurrence and rejection can be challenging d) Significant hypoesthesia can lead to recurrent trauma and exposure keratopathy cants, prophylactic broad-spectrum antibiotics, cycloplegic, Oral antivirals 3.2.Diffuse: Topical corticosteroids, preservative free lubricants, prophylactic broad-spectrum antibiotics, cycloplegic, Oral antivirals and corticosteroids 3.3.Linear: Topical corticosteroids, preservative free lubricants, prophylactic broad-spectrum antibiotics, cycloplegic, Oral antivirals and corticosteroids Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 41 Deep anterior lamellar keratoplasty may have similar or superior outcomes in cases of superficial scarring but cannot be performed in deeper scars.[10] Atleast 6 months of oral acyclovir is given in the postoperative period to reduce the rates of recurrent infection. Emerging Therapies Corneal neurotization is a relatively novel procedure in the treatment of neurotrophic keratitis that permits restoration of innervation to the insensate cornea, thereby restoring sensation and nerve-derived trophic support of the corneal epithelium.[11] Cationic peptides such as retrocyclin-2 and TAT-Cd, were reported to show efficacy in treating ocular HSV1 infections. Their efficacy declines when applied 24 hours post-infection or longer. Hence, their role is limited in treating patients that already have developed HSK.[12,13] The PDK1 inhibitor, BX795 is effective when administered either therapeutically or prophylactically. This drug inhibits the phosphorylation of Akt at Ser473, thus inhibiting viral protein synthesis. This may develop into an alternative to nucleoside analog therapy, extremely useful in patients with resistance to acyclovir or its derivatives.[14] An activated carbon-based drug delivery system termed DECON (Drug Encapsulated Carbon) can be used to deliver acyclovir in a sustained manner. This delivery system was able to replace currently prescribed threetimes per day dosage requirement to once every alternate day.[15] Conclusion HSK is primarily a clinical diagnosis based on the findings of the slit-lamp examination. Laboratory tests, such as PCR assay, ELISA, IFA and viral cultures are helpful in confirmation of diagnosis with their own set of drawbacks. Moreover, variation in different subtypes of keratitis has made diagnosis of atypical lesions difficult. Accurate and prompt diagnosis is necessary to aid the physician in initiating appropriate treatment that will prevent further complications. References 1. Darougar S, Wishart MS, Viswalingam ND. Epidemiological and clinical features of primary herpes simplex virus ocular infection. Br J Ophthalmol. 1985;69(1):2–6. 2. Tsatsos M, MacGregor C, Athanasiadis I, Moschos MM, Hossain P, Anderson D. Herpes simplex virus keratitis: an update of the pathogenesis and current treatment with oral and topical antiviral agents. Clin Exp Ophthalmol. Epub 2016 Jun 8. 3. Satpathy G, Mishra AK, Tandon R, et al. Evaluation of tear samples for herpes simplex virus 1 (HSV) detection in suspected cases of viral keratitis using PCR assay and conventional laboratory diagnostic tools. Br J Ophthalmol. 2011;95(3):415–418. 4. Shoji J, Sakimoto T, Inada N, et al. A diagnostic method for herpes simplex keratitis by simultaneous measurement of viral DNA and virus-specific secretory IgA in tears: an evaluation. Jpn J Opthalmol. 2016;60(4):294–301. 5. Kowalski RP, Gordon YJ, Romanowski EG, Araullo-Cruz T, Kinchington PR. A comparison of enzyme immunoassay and polymerase chain reaction with the clinical examination for diagnosing ocular herpetic disease. Ophthalmology. 1993;100(4):530–533. 6. Seitzman GD, Cevallos V, Margolis TP. Rose bengal and lissamine green inhibit detection of herpes simplex virus by PCR. Am J Ophthalmol. 2006;141(4):756–758. 7. Wilhelmus KR. Antiviral treatment and other therapeutic interventions for herpes simplex virus epithelial keratitis. Cochrane Database Syst Rev. 2015;1:CD002898. 8. Vadlapudi AD, Vadlapatla RK, Mitra AK. Update on emerging antivirals for the management of herpes simplex virus infections: a patenting perspective. Recent Pat Antiinfect Drug Discov. 2013;8(1):55– 67. 9. Barron BA, Gee L, Hauck WW, Kurinij N, Dawson CR, Jones DB, Wilhelmus KR, Kaufman HE, Sugar J, Hyndiuk RA, et al. Herpetic Eye Disease Study. A controlled trial of oral acyclovir for herpes simplex stromal keratitis. Ophthalmology. 1994 Dec;101(12):1871-82. 10. Ren Y, Wang H, Zheng Q, et al. Long-term outcomes of deep anterior lamellar keratoplasty treating posterior stroma-implicated herpetic corneal opacities. Cornea 2016; 35:299–304. 11. Terzis JK, Dryer MM, Bodner BI. Corneal neurotization: a novel solution to neurotrophic keratopathy. Plast Reconstr Surg 2009; 123:112–120. 12. Brandt CR, Akkarawongsa R, Altmann S, Jose G, Kolb AW, Waring AJ, Lehrer RI, 2007. Evaluation of a theta-defensin in a Murine model of herpes simplex virus type 1 keratitis. Invest. Ophthalmol. Vis. Sci 48, 5118–5124. 13. Jose GG, Larsen IV, Gauger J, Carballo E, Stern R, Brummel R, Brandt CR, 2013. A cationic peptide, TAT-Cd°, inhibits herpes simplex virus type 1 ocular infection in vivo. Invest. Ophthalmol. Vis. Sci 54, 1070–1079. 14. Clark K, Plater L, Peggie M, Cohen P, 2009. Use of the Pharmacological Inhibitor BX795 to Study the Regulation and Physiological Roles of TBK1 and IκB Kinase. Journal of Biological Chemistry 284, 14136–14146. 15. Koganti R, Yadavalli T, Shukla D, 2019a. Current and Emerging Therapies for Ocular Herpes Simplex Virus Type-1 Infections. Microorganisms 7. Dr. Prafulla Kumar Maharana, MD Associate Professor, Dept. of Ophthalmology Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi. Corresponding Author: Corneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 42 Missed Anterior Segment Intra Ocular Foreign Body: Fungal Keratitis Masquerading as Viral Keratitis Gunjan Verma Shah, MS, DNB Gunjan Eye Hospital, 306, Copper Leaf, Bhuyangdev Char Rasta, Ahmedabad, Gujarat. Abstract: A 23 year old male presented with keratitis which was diagnosed to be viral in origin elsewhere and treated accordingly. A careful examination revealed foreign body on endothelial side along with exudates. After foreign Body removal, intrastromal Voriconazole and topical antifungal treatment was given. Complete recovery of lesion and improvement in visual acuity was noted. This case indicates the importance of thorough and meticulous examination. Ruling out Foreign Body in non responding keratitis is of utmost importance. Case A 23 year old male presented with pain, watering, foreign body sensation and diminution of vision in Right Eye for last 2 months. No history of contact lens wear. Patient was not sure about trauma. He was diagnosed elsewhere as viral keratitis and instilling Moxifloxacin Dexamethasone eyedrops four times per day, Chloremphenicol eye ointment Three times per day, Tropicamide eyedrops three times per day, Acyclovir eye ointment five times per day. He was worsening on above said treatment and was referred for further management. Visual acuity was Counting Finger close to face on presentation. On examination, eyelid swelling was noted. On Slit Lamp Examination, diffuse corneal edema with Ring infiltrate with Keratic precipitates were noted. Localized endothelial exudates were noted at 8 o’clock position, paracentral area. (Figure-1) On careful Slit Lamp examination, Small Foreign body was noticed on endothelial side. (Figure-2) Flourescein stain of the lesion was negative. Patient was found to be HbsAg Reactive, rest blood investigations were within normal limits. Steroid eyedrops were stopped and patient was posted for Foreign Body removal with anterior chamber tap (Figure-3). Detailed written informed consent was taken. Microbiology examination of tap was KOH (Potasium Hydroxide prep) positive and fungal growth was noted on Sabouraud Dextrose Agar. Subsequent Intrastromal voriconazolen (50 microgram/0.1ml) was administered at the junction of clear cornea and infiltrates, using a 30-gauge needle in five quadrants to form a barrage around the ulcer. Procedure was done in operation theatre under Universal aseptic precautions. Post operatively, patient was started on Natamycin eyedrops Figure 1: Diffuse corneal edema with Ring infiltrate with Keratic precipitates were noted. Localized endothelial exudates were noted at 8 o’clock position, paracentral area. Figure 2: Foreign Body noted on slit lamp examination. Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 43 (5%) every one hourly, Fortified Voriconazole eyedrops every two hourly and atropine eyedrops three times per day. After the intervention, faster reduction in size of infiltrate was noted and complete recovery within 3 months was observed (Figure 4-9). Uncorrected visual acuity on last follow up was 6/18. Figure 3: Magnified view of foreign body. Figure 6: 15 days follow up Figure 7: 1 month follow up Figure 8: 3 months follow up Figure 4: 3 days follow up Figure 5: 10 days follow up Foreign Body Corneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 44 Figure 9: 6 month follow up Discussion Keratitis is a medical emergency which needs prompt management. Fungal keratitis poses a great challenge in diagnosis and management. Delay in diagnosis and inadvertent usage of antibiotic has led to emergence in recalcitrant cases. Fungal infections may present with a variety of clinical presentations. Deep mycotic keratitis are not amenable to topical antimicrobial therapy because none of the present day antifungal agents can optimally penetrate the deeper layers of cornea. Detailed history taking is very important as it may point subtly to diagnosis. Meticulous clinical examination and detailed microbiology work up is necessary for optimal results. Conflict of Interest Statement The authors declare no conflict of interest. References 1. Evalaution of Intrastromal Injection of Voriconazole as a therapeutic Adjunctive for the management of Deep Recalcitrant Fungal Keratitis. Gaurav Prakash, Namrata Sharma, Manik Goel, Jeewan S Titiyal, Rasik B.Vajpayee. American Journal of Ophthalmology, Volume 146 Issue 1, July 2008, Page 56-59. 2. Comparative evaluation of topical versus intrastromal voriconazole as an adjunct to natamycin in recalcitrant fungal keratitis. Namrata Sharma 1, Jacob Chacko, Thirumurthy Velpandian, Jeewan S Titiyal, Rajesh Sinha, Gita Satpathy, Radhika Tandon, Rasik B Vajpayee. Ophthalmology 2013 APR ;120(4):677-81. 3. Evaluation of intrastromal voriconazole injection in recalcitrant deep fungal keratitis: case series. Namrata Sharma 1, Prakashchand Agarwal, Rajesh Sinha, Jeewan S Titiyal, Thirumurthy Velpandian, Rasik B Vajpayee.Br J Ophthalmol 2011 Dec;95(12):1735-7. doi: 10.1136/ bjo.2010.192815. Epub 2011 Mar 31. 4. Voriconazole for fungal corneal ulcers Swapnil Parchand, Amit Gupta, Jagat Ram, Nishant Gupta, Arunaloke Chakrabarty. Ophthalmology. 2012 May;119(5):1083. doi: 10.1016/j.ophtha.2011.11.034. 5. Fungal Keratitis: Clinical Features, Risk Factors, Treatment, and Outcomes.Sarah Atta,Chandrashan Perera, Regis P Kowalski, Vishal Jhanji.J Fungi (Basel). 2022 Sep 15;8(9):962. doi: 10.3390/jof8090962. 6. Update on diagnosis and management of refractory corneal infections.Shweta Agarwal, Tanveer A Khan, Murugesan Vanathi, Bhaskar Srinivasan, Geetha Iyer, Radhika Tandon.Indian J Ophthalmol . 2022 May;70(5):1475-1490. doi: 10.4103/ijo.IJO_2273_21. Dr. Gunjan Verma Shah, MS, DNB Gunjan Eye Hospital, 306,Copper Leaf, Bhuyangdev Char Rasta, Ahmedabad, Gujarat. Corresponding Author: Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 45 Fungal Keratitis – A Potpourri of Interesting Cases Mayur Jain, MS, Sonali Mehta, DNB, Mehak Vohra, PHD, Arpan Gandhi, MD, Manisha Acharya, MS Cornea department, Dr Shroff’s Charity Eye Hospital. Abstract: In India, fungal keratitis accounts for nearly 50% of all the cases of infectious keratitis. Fungal keratitis poses a significant diagnostic as well as therapeutic challenge due to delayed presentation which occurs as a result of paucity of symptoms, as well as due to longer time to obtain cultures and its refractory nature to conventional treatment. Treatment modality of fungal keratitis depends upon its severity. While most infections can be treated by conservative management, early surgical interventions in the form of intra stromal antifungals, or Therapeutic Penetrating Keratoplasty is required in some patients. Documentation of findings in the form of corneal diagrams and slit lamp photographs is very important tool in right management of fungal keratitis. In this excerpt, we shall present 5 well documented fungal keratitis patients with different presentations and thereby different treatment modalities. India is an agricultural country that lies in the tropical climate zone, and fungal keratitis accounts for nearly 50% of all cases of infectious keratitis.[1,2] Classically, fungal keratitis occurs due to trauma with vegetative matter presenting with a drylooking ulcer, raised plaque-like infiltrates, satellite lesions, and a fixed hypopyon.[3] Protocol for management of such cases includes a detailed history, thorough clinical examination, and microbiological testing viz., KOH mount of corneal scrapping and cultures on Sabouraud Dextrose Agar (SDA). Apart from the other causative fungi, the commoner species also vary geographically, with Aspergillus species being more common in north India while, Fusarium species is more common in the south.[4,5,6] In the Delhi Infectious Keratitis Study, a study conducted by our centre in 2017-18, out of 393 culture-proven keratitis, bacterial culture accounted for 60.6% (238/393) and fungal cultures were 143 (36.4%). Fusarium sp. was the most common fungus isolated.[7] Fungal keratitis poses a significant diagnostic as well as a therapeutic challenge not only due to delayed presentation which occurs as a result of paucity of symptoms but also due to the longer time to obtain cultures and its refractory nature to conventional treatment. Most infections can be treated by conservative management, but early surgical interventions in the form of intra-stromal antifungals, or Therapeutic Penetrating Keratoplasty is required in some patients. In Delhi Infectious Keratitis Study, one-third of the cases required surgical intervention, and the remaining two-thirds were managed medically.[7] In this excerpt, we are presenting a case series of varying presentations of fungal keratitis with pearls of management and the importance of clinic-microbiological correlation. Case - 1 and 2 Our first Two cases presented with the classical clinical picture of fungal keratitis. Both cases had a central epithelial defect with a dry-looking, raised plaque, superficial stromal infiltrates with feathery margins and surrounding mild corneal edema. The second patient also had a 2 mm hypopyon. Corneal scrapings were performed and the samples were sent for Gram stain, KOH wet mount, and cultures on blood agar (BA), chocolate agar (CA), and Sabouraud Dextrose Agar (SDA). The KOH wet mount of both patients revealed septate branching fungal hyphae. On the culture plates, growth of raised, yellowish-white, cottony colonies were seen, suggestive of Fusarium species. The patients were managed conservatively with intensive topical medical treatment consisting of hourly natamycin suspension (5%) and cycloplegics thrice a day for one week. For the first week, the patient was followed up frequently and debridement was done at each visit to reduce the microbial load. Signs of improvement were seen within a week and natamycin was then tapered to a 2-hourly frequency Both the patients healed with faint nebular grade corneal scarring and BCVA of 6\9 and 6\12 respectively. (Figure 1 and 2) Figure 1: Fungal keratitis right eye. A: Slit lamp photograph of right eye in diffuse illumination showing 2* 1.5 mm para central epithelial defect with plaque and superficial stromal infiltrates. B:Blood agar, chocolate agar, and Sabouraud Dextrose Agar (SDA) showing yellowish white cottony raised growths suggestive of Fusarium species. C: Healed keratitis - nebular scarring. Corneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 46 CLINICAL PEARLS : As per MUTT trial, Natamycin is the first choice topical anti fungal and is given as monotherapy, especially in Fusarium sp.[8] Case - 3 - A Diagnostic Dilemma A 19-Year-old male presented with pain, watering, and redness in the right eye for one week. He was being treated for right eye viral keratitis from outside. BCVA was 6/36 in the right eye and 6/6 in the left eye. There was no history of recurrent redness in either eye. Slit lamp examination showed a 5✕3 mm central corneal epithelial defect with 2.5✕2.5 mm superficial and deep infiltrates (yellowish white) and surrounding corneal oedema. A streak hypopyon was also present in the anterior chamber. Along with other microbiological investigations, a smear was also evaluated with the Giemsa stain given the suspected viral etiology. Gram stain revealed 2-4 Gram-Positive Cocci (GPCs) while other tests were negative. Hence the patient was started on anti-bacterial eye drop levofloxacin 1.5% hourly, along with cycloplegics and lubricants. A 4-day follow-up examination Figure 3: Fungal keratitis right eye. A: Slit lamp photograph of right eye in diffuse illumination showing central epithelial defect with superficial and deep infiltrates, streak hypopyon. B: Superficial infiltrates started resolving but deeper ones increased. C: Post intrastromal voriconazole 50 microgram/O. lmL. Figure 2: Fungal keratitis right eye. A: Slit lamp photograph of right eye in diffuse illumination showing 3*5 mm epithelial defect with grayish white superficial and deep stromal infiltrates (superficial > deep). B: Healing keratitis. C: Healed keratitis. revealed worsening in keratitis with increased infiltrates and an increase in the size of the epithelial defect. In view of the worsening clinical picture, repeat corneal scraping was performed and sent for microbiological evaluation. The KOH wet mount from this sample revealed septate fungal hyphae, and the cultures had growth suggestive of Fusarium species. We, therefore, switched the treatment to antifungals, including suspension natamycin 5% hourly, eye drop voriconazole 1% 2 hourly, along with cycloplegics and lubricants. Three days after the modified treatment, superficial infiltrates started reducing, but deeper stromal infiltrates had increased. Hence, intrastromal voriconazole 50 microgram/0.1mL was injected. Two more doses of intrastromal voriconazole were injected at intervals of 3 days each until the deep infiltrates also started to resolve. The keratitis healed with a BCVA of 6/12. (Figure-3) Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 47 Case - 4 A 21-year-old male presented with 7 days history of watering and redness in the right eye. BCVA was 6/18 OD and 6/6 OS. A slit lamp examination in the right eye revealed two paracentral corneal epithelial defects with anterior stromal infiltrations - 2*2 and 1*1mm respectively, with dendritic/fuzzy borders. The patient was being treated on topical anti-viral acyclovir 3% 5 times per day from outside. Viral etiology was suspected clinically, and hence, the anti-viral treatment was continued. 4 days later the patient presented with an increased size of the epithelial defect and the infiltrates. Corneal scraping was performed and the sample was sent for Gram stain, KOH wet mount, and cultures on blood agar (BA), chocolate agar (CA), Case - 5 A 42-year-old male patient presented with complaints of Figure 4: Fungal keratitis right eye. A: Slit lamp photograph of right eye in diffuse illumination showing 2 epithelial defects with anterior stromal infiltrates with dendritic margins. B: Increasing epithelial defect and infiltrates. C: Giemsa stain (40X) - Viral Cytopathic changes - I. Cytoplasmic granulation s 2. Inclusion bodies in nucleus. D: Increasing epithelial defect and infiltrates. E: Healed keratitis. CLINICAL PEARLS : 1. ALWAYS KNOW YOUR ENEMY. Re-scrape when in doubt. 2. Indications of Intrastromal voriconazole[9]: • Recalcitrant cases • Non responding to topical natamycin and voriconazole for 2 weeks watering, ocular pain and redness in the left eye. There was a history of trauma to the left eye with an insect while driving three and Sabouraud Dextrose Agar (SDA). Gram stain revealed 1-2 GPC, and KOH wet munt was negative for fungal hyphae. Giemsa stain was also performed which revealed viral cytopathic changes. Oral anti-viral tablet acyclovir 400mg 5 times per day and topical antibiotic levofloxacin 1.5% 2 hourly were added to the topical anti-viral treatment. 4 days later, the patient presented with further worsening. By this time, culture plates revealed growths of unidentified dematiaceous fungi. The treatment was modified to antifungals, including suspension natamycin 5 % every hour OD along with cycloplegics and lubricants. Eventually, the keratitis healed in 2 months, with central nebular scarring and BCVA of 6/18 OD. (Figure-4) Corneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 48 weeks back. BCVA was 6/6 in the right eye and hand movements in the left eye. Slit lamp examination showed a 7*5 mm epithelial defect with 3*3mm superficial corneal infiltrates, surrounding 8*8mm deep stromal infiltrates, and a 1.5mm yellowish hypopyon in the anterior chamber. B scan showed an echo-free vitreous cavity. Both, the Gram stain and the KOH wet mount of the corneal scrapings revealed fragmented fungal hyphae. A baseline liver function test was done and we started the patient on tab ketoconazole. Along with oral medications, intensive topical medical treatment was also started which included topical natamycin suspension (5%) hourly and cycloplegics. On a 3 - day follow-up examination there was the consolidation of the infiltrates and the hypopyon had also reduced. At this visit, the culture plates showed growth of olive green, woolly colony, suggestive of dematiaceous fungus (Curvularia species). A planned Therapeutic Penetrating Keratoplasty was done for this patient due to a large-size infiltrate and severe corneal thinning. One month postoperatively, the graft was well attached, with no evidence of infection, and BCVA 6/60 OS. Figure 5: Fungal keratitis left eye. A: Slit lamp photograph of left eye in diffuse illumination showing 7*5 mm epithelial defect with 3*3mm superficial corneal infiltrates, surrounding 8*8mm deep stromal infiltrates, and a 1.Smm yellowish hypopyon. B: 10% KOH mount preparation revealing dark, septate hyphae and conidia which are large , containing 3- 4 cells, and curved; suggestive of Dematiaceous fungus curvularia specie. C: Deeper infiltrates slightly reduced, superficial infiltrates status quo. D: Dark I olive green , woolly colony, suggestive of Dematiaceous fungus curvularia specie. E: Post Therapeutic Penetrating Keratoplasty POD 1 week. CLINICAL PEARLS : 1. Indications of oral anti fungal in management of fungal keratitis[10]– • ulcers >5mm • involvement of >50% of stromal depth, • scleral or limbal involvement • Endophthalmitis • impending perforation, or perforated corneal ulcer • post keratoplasty 2. Predictors of corneal perforation or need of Therapeutic Penetrating Keratoplasty in severe fungal keratitis[11]: • Presence of hypopyon at baseline • Involvement of posterior 1/3 • Increase in size of infiltrate Corneal Infections

www.dosonline.org/dos-times DOS Times - Volume 28, Number 5, September-October 2022 49 References 1. Shokohi T, Nowroozpoor-Dailami K, Moaddel-Haghighi T. Fungal keratitis in patients with corneal ulcer in Sari, Northern Iran. Arch Iranian Med. 2006;9(3):222–227. 2. Nath R, Baruah S, Saikia L, Devi B, Borthakur AK, Mahanta J. Mycotic corneal ulcers in upper Assam. Indian J Ophthalmol. 2011;59(5):367–371. 3. Sudan R, Sharma YR. Keratomycosis: clinical diagnosis, medical and surgical treatment. JK Science. 2003;5(1):1–10 4. Thomas PA. Fungal infections of the cornea. Eye (Lond) 2003;17(8):852–862. 5. Chowdhary A, Singh K. Spectrum of fungal keratitis in North India. Cornea. 2005;24(1):8–15. 6. Gopinathan U, Garg P, Fernandes M, Sharma S, Athmanathan S, Rao GN. The epidemiological features and laboratory results of fungal keratitis: a 10-year review at a referral eye care center in South India. Cornea. 2002 Aug;21(6):555-9. 7. Acharya, M., Farooqui, J. H., Gaba, T., Gandhi, A., & Mathur, U. (2020). Delhi Infectious Keratitis Study: Update on Clinico-Microbiological Profile and Outcomes of Infectious Keratitis. Journal of Current Ophthalmology, 32(3), 249-255. 8. Prajna NV, Krishnan T, Mascarenhas J, Rajaraman R, Prajna L, Srinivasan M, Raghavan A, Oldenburg CE, Ray KJ, Zegans ME, McLeod SD, Porco TC, Acharya NR, Lietman TM; Mycotic Ulcer Treatment Trial Group. The mycotic ulcer treatment trial: a randomized trial comparing natamycin vs voriconazole. JAMA Ophthalmol. 2013 Apr;131(4):422-9. 9. Kalaiselvi G, Narayana S, Krishnan T, Sengupta S. Intrastromal voriconazole for deep recalcitrant fungal keratitis: a case series. Br J Ophthalmol. 2015 Feb;99(2):195-8. Dr. Mayur Jain, MS Fellow in Cornea and Anterior Segment, Dr Shroff’s Charity Eye Hospital. Corresponding Author: 10. Sahay P, Singhal D, Nagpal R, et al. Pharmacologic therapy of mycotic keratitis. Surv Ophthalmol. 2019;64(3):380-400. 11. Prajna NV, Krishnan T, Rajaraman R, Patel S, Shah R, Srinivasan M, Das M, Ray KJ, Oldenburg CE, McLeod SD, Zegans ME, Acharya NR, Lietman TM, Rose-Nussbaumer J; Mycotic Ulcer Treatment Trial Group. Predictors of Corneal Perforation or Need for Therapeutic Keratoplasty in Severe Fungal Keratitis: A Secondary Analysis of the Mycotic Ulcer Treatment Trial II. Corneal Infections

DOS Times - Volume 28, Number 5, September-October 2022 www.dosonline.org/dos-times 50 Pediatric Keratitis: The Salient Points in Management Shweta Singh, MS, Abha Gour, DOMS, Manisha Acharya, MS Cornea and Anterior Segment, Dr Shroff’s Charity Eye Hospital, New Delhi. Introduction Pediatric keratitis, though unusually seen, accounts for 11-13% of the burden of total infectious keratitis.[1,2] The incidence is around 20 times higher in developing countries.[3] The risk factors, microbiological agents, examination techniques, and management protocols are all distinct from those in adult keratitis. The preliminary difficulties faced in pediatric keratitis include: 1. Difficulty in obtaining a relevant medical history. 2. Difficulty in examining the children; most of these will require an examination under anaesthesia. 3. A severe inflammatory response is seen in children, which might increase the severity of clinical presentation. 4. The unique risk of causing irreversible morbidity induced by amblyopia. Pediatric corneal infiltrates may be: a. Inflammatory: including vernal keratoconjunctivits, phlyctenular conjunctivitis, chronic blepharo-keratoconjunctivitis, ocular rosacea, etc. b. Infective: including bacterial, fungal, viral, parasitic, etc. Predisposing Factors The most common predisposing factor for keratitis in children is trauma. Various studies show trauma as a primary factor in up to 58.8% of pediatric keratitis cases.[1,4,5] The other risk factors commonly reported are co-existing ocular or systemic diseases. The ocular conditions increasing the risk of keratitis in children include exposure keratopathy, dry eye, limbal stem cell deficiency, shield ulcer, post-ocular surface surgeries, etc. These conditions may be secondary to long-term steroid use to manage ocular surface disorders.[6-11] The systemic associations of keratitis in children included systemic infections, malignancies and protein energy malnutrition. This is one of the most significant reasons for its increased inAbstract: Pediatric keratitis is a sight-threatening clinical entity with its own challenges in diagnosis and management. These require a unique approach because of complexities such as an unreliable history available for diagnosis, the need for multiple examinations under anaesthesia, difficulty in administering topical medications and the risk of development of amblyopia. These features make it distinct from the management of adult keratitis. In this article, we aim to describe the common predisposing factors, the microbiological review, and the approach to management and rehabilitation measures concerning pediatric keratitis. cidence in low socioeconomic strata and developing nations. These cases are usually associated with bilateral corneal involvement. The other systemic associations reported are hypoxic encephalopathy, severe prematurity, congenital structural anomalies of the heart or pulmonary system, cerebral palsy and diabetes.[1,2,4,5,12-15] Contact lens wear in children, especially with the advent of orthokeratology for myopia management, is another significant risk factor, especially in developing nations.[1,2,4] Diagnosis The diagnosis of pediatric keratitis is complicated by the following: a. Delayed presentation b. Inadequate/unreliable history c. Poor cooperation for evaluation d. Prior empirical use of antimicrobials decreases the rates of culture positivity. Detailed evaluation under a slit lamp or examination under anaesthesia is mandatory, with corneal scrapings for microbiological evaluation. The microbiological evaluation kit should include 2-3 slides for Gram’s staining, KOH mount and Giemsa stain. Culture plates commonly included in the microbiology kit include blood agar, chocolate agar, Sabouraud dextrose agar, brain heart infusion broth, thioglycolate media, and Lowenstein-Jensen media. This kit provides the scope to culture the spectrum of common ocular pathogens, including fastidious bacteria, fungi, micro-aerophilic, anaerobic organisms and mycobacteria. During the evaluation, the details of infiltrates are noted, including the size, location and depth of infiltrates; any associated vascularisation needs to be noted with a keen assessment to rule out corneal thinning, perforation or any retained foreign body. Multiple serial examinations under anaesthesia may be necessary to see the course of the disease. Corneal Infections