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A ‘Teach to Reach’ Initiative CLINICAL EMBRYOLOGY OF THE EYE An Illustrated Manual 1st Edition Dr Pranesh Medical Officer Aravind Eye Hospital and PG Institute of Ophthalmology Coimbatore 3oz
PREFACE Embryology of eye is a difficult topic to master - due to the obscure understanding of general principles and lack of application of the learned concepts in our routine practice. This handwritten manual aims to bridge the knowledge gaps & missing links - thereby presenting itself as a Complete Course on Ocular Embryology from Genes to Clinics. Highlights : ① Profusely illustrated with colourful diagrams and clinical photographs ② Flowcharts to aid understanding of complex derivatives ③ Every detail on individual structure is accompanied by relevant applied aspects ④ Must read for residents, practicing ophthalmologists and paediatricians
CONTENTS 1. General Embryology - Overview 2. Ocular Embryology - Overview 3. Brief summary of Derivatives 4. Development of specific Ocular structures a) Optic Nerve b) Retina c) Retinal Vasculature d) Hyaloid Vasculature e) Vitreous f) Sclera & Choroid g) Iris & Ciliary Body b) Lens i) Cornea j) Angle of Anterior chamber k) Lids & Adnexa 5. Genetics - in Brief + Discussion on Coloboma 6. Big Picture + Summary repeated 7. References Basics with relevant clinical aspects
GENERAL EMBRYOLOGY 3 Germinal Layers I b t Ectoderm Mesoderm Endoderm t I 4 No Surface Neuro Neural contributionto Ectoderm deum g oculardevelop Mesenchyme Note Contributes to Eye Development Mesenchyme Nut Mesoderm NCC's contribution Mesodermal Mesenchyme contribution So for all practical purposes here Ncc Mesenchym
3 Layers 0 formed finishesKydd wk
Gastrulation Neurulation T Formationof neural formationof3germindlayes tube cranial a pole cross section caifdalpole
Neuralcrest T Neuro ectoderm from neuro ectoderm Neurulation
03 is Neural Tube c 3 Vesiclesformation
OCULAR EMBRYOLOGY Day22 lsteventineyedevelop
Neuro ectoderm Tencephalon Thickening ofsurfaceectoderm
dotes by 7thwk if not closed Coloboma OpticCup Inner layer Neurosensory Retina Outer Layer RetinalPigmentEpithelium
migrating Ncc cells Ncc x
SUMMARY must know
Optic Nerve Neuro ectoderm Hyaloid vessels Central RetinalHall
Congenital OpticDiscAnomalies Congenital oD Pit focal excavation on 0NHead Examine Discin central serous petinopMM If I Serious 1 pit detachment
OD Dusen focal collectionsof axonal metabolic products calcified deposits within ONH Buried dmsen Pseudo papilledema
Morning Glory Anomaly variantof OD loloboma Geneinvolved PAX6 Axial Coloboma M c systemic Association FrontoNasal Dysplasia CNS disorders associated Neuroimaging required Large disc tunnelshapedexcavation Ringof Chorioretinaldisturbance spokesofwheel pattern of radially emerging vessels Details of ODcoloboma discussed in the Last section of the manual
Myelinated Nervefibres Medullated Nerve fibres progression of myelination starts from optictract Lamina Cribwsa ends Lc of Sdera CLA t if Oligodendrocytes migrate into intraocular area Abnormal myelination of Ganglion cellAxons b'yond LC I
Optic N Hypoplasia fed Nerve f snes Uk Squint Bk Nystagmus I AbsentCorpusCallosum Septum Pellucidum de Morsier syndrome 7 Bk on Hypoplasia septo optic dysplasia7 Hypopituitarism I
RPE Reti na n Neuro sensory retina Edmondinn d L Marginalzone TransientLayer of Chievitz
Macularitoveal Development Foreal maturation 4thmonth Fixation completes Reflex I if impaired Nystagmusdevelops eg.in Albinism
Retinal Vasculature t Of 2nd I 1st TemporalRetina Nasalretina fullyvascularised by fully Vascularised Imonth after birth by8thmonth of GA H i IncompleteVascularisation of Retina in Preterm infants Vascularisation occurs in Low O2 tension in utero
n't RETINOPATHY of PREMATURITY In Preterminfants 02supplementation given for lung immaturity 902Tension 1 Growth of PeripheralRetinal Vesselsout off Retina thinks no need for vessels dueb ROD Oz removed Ischemic response abnormal vessel production t Leahy new vessels fibrovascular 4 Tissues Retinopathy of Prematurity prop
RetinalVascular Anomalies
familial ExudativeVitteoRetinopathy I 1119 to Rop Tt failureof Xascularisation of Temporal Retina Screen the relatives of PE E FEUR
Hyaloid Vasculature pinkaneural portionof Hyaloidvessels t central Retinal A'eV ya aeagyeof yfgawdue.se TunicaVasculosa TUL refresses in Thrimestv Lenh's Regressed PrimaryVitreous 3 components t AnteriorVascularCapsule Cloquet's Canal Ant pupillarymembrane x Capsulopupillaryportion Details below PosteriorVascularCapsule Post Pupillarymembrane
Persisting pupillary Membran Mittendorf Dot BergMeister papilla
ft t Mittendorf Bergmeisterpapilla Persistent persistent fetalVasculature HyaloidArtery Retrolentalmass
Vitreous
Vitreous Development t.de Pnimary PrimiliveSeconday Tertiary Definite.ve ViFeousPwpev From Mesenchyme of Ncc From 7mm NeuroEctoderm Neuro Ectoderm Surface Ectoderm 1 month 2ndmonth 374 month Vascular AVascular Becomes 1 Vitreous whenzolineous fillsthe cavity Basee fills cavity it fwmjtfyafoyt.es Ciliary2onules becomes Cloquet's Canal
Persistent Hypoplastic PrimaryVitreous Persistent Fetal Vasculature t t t Persistent Anterior Persistent Posterior Fetal Vasculature Fetal Vasculature t t Reholental fibrovascular Mass RetinalDetachment LEUCOCORIA 11 DifferentialDiagnosis Retinoblastoma Persistent 7daL Vasculature Rop congenital Cataract RetinalDysplasia Goat's disease Toxocara Coloboma Choroid Endophthalmitis ODisc
Persistent fetal Vasculature Persistent AnteriorFetal Vasculature
Scleras choroid Ncc continues Anteninly Posteriorly sclera Substantia propria ofcornea Dura choroid Ciliary Body PiaArachnoid
SCLERA T hotherparkofsdera Tempyalsdera I t from Mesoderm from NCC mesenchyme Mesenchyme
Iris ciliary Body Outerlayer of opticup Inner layerof opticCup Mff DIn's fromNeuwectoderm Muscleof CB Ciliarymuscle from NCC
Vascular mesenchyme Pupillary membrane opticCupmargin Neuroectoderm cma ciliary muscle CB CiliaryBody Tm Trabecular Mesh SS scleralspur J Iris Retina
schlemm'scanal 0 Cp Ciliary Processes PosteriorNon Pigment U Epithelium ofdeveloping in's Attains melaninpigment Melanogenesis Ut Becoming Posterior Pigmented Epithelium of Iris
Melanocytes FT Ncc derived Neuwedndermal derived t t choroid RPE skinehair Epithelium't f Irisa ciliary body Race related to pigmented in all races If affected melaninproduction d ALBINISM Oaelocutaneous Ocular
Oculocutaneous Albinism Tyrosinase negative Ilusinase complete Incomplete til Hariable Melanin Not capableof producing production melanin
c Let us review Iris developmen again Aniridia PAX 6 gene mutation AutosomalDominant BIL condition misnomer not complete absenceof iris Abnormal Iris seen as a stump of hypercellularstroma Leadsto malformed outflowsystem Glaucoma syndrome associated 75 t L WAGR syndrome WIM'sTumor Aniridia WT mutation Genitourinary abnormalities Retardedmental status
Do 456 Abdomen for all cases of sporadic Aniridia to detectWim's Tumor Partial Aniridia Total Aniridia
Associated features of Aniridia calaraff subluxation 701gal Hypoplasia Assoc Limbalstem Poor'Exation cell deficiency to Nystagmus
Lens Surface Ectoderm f formed in 4th7kWh Affected in Rubella in 1sttrimester y primam congenital lens cataract fibres f Equatorial LensBow Embryonic Nucleus
Lens Vesicle v d Anterior epithelium posterior 1 epithelium equatortorms t secondaryLensfibres elongates loses 1 SLF formprimaylensmoki fibres fetal Nucleus 1 Infantile Nucleus Embryonic AdultNucleus Nucleus Coney H centralcore i oldestfibres SLF grows anteriorly posteriorly Feet y sutures suture dotted area t anteriorly straight'Y iii posteriorly inverted1 i i
CONGENITAL CATARACT I t I 43rd 43rd y H Notassoci Assoc I systemicillness t Nonsyndromic Metabolic Intrauterine Hereditary disorder Infections I 1 Syndromes Human gamma Erystallins intens tens proteins Genes encoding crystalline mutations 1 Cataractduetsprotein misfolding