CME Complex Strabismus

Superior Oblique Palsy

coherent tomography. (Figure 4) When the fovea is located below
the lower edge of the optic nerve head, it is a sign of excyclotorsion.
Although they show large fundus excyclotorsion, patients with
congenital SOP usually do not complain of torsional diplopia.

Excyclotorsion

Figure 2: Double Maddox rod test

Figure 3: Synoptophore 45
CME on COMPLEX STRABISMUS

Superior Oblique Palsy

Figure 4: Objective cyclotorsion evaluated with fundus photograph and OCT

3) Versions
The common findings of the versions are 1) over-elevation in

adduction (inferior oblique muscle overaction: IOOA), 2) under
depression in adduction (superior oblique underaction), and 3)
contralateral over-depression in adduction (contralateral superior
oblique overaction: contralateral SOOA). Contralateral SOOA
should be recognized as a sign of SOP, and one should avoid
weakening the contra lateral SO as; it may create iatrogenic
bilateral SOP.
4) Bilateral SOP 7
Bilateral SOP should be suspected in a patient with a combination
of the following: (1) SOP after closed head trauma; (2) subjective
complaints of torsion; (3) objective torsion exceeding 10 degrees;
(4) alternating hypertropia on head tilt; (5) V-pattern exotropia
and (6) chin-down head posture.
5) Imaging studies
Coronal MRI is helpful to confirm SOP. Seventy percent of
patients with SO muscle atrophy fulfilled the entire three-step
test. In 28% of patients, two steps are fulfilled, and 2% of patients
fulfilled only one step. If MRI is not available, use of only Steps 1
and 3 would increase the sensitivity to 84%.8 (Figure 5)

46 CME on COMPLEX STRABISMUS

Normal SO Superior Oblique Palsy
Hypoplastic SO

Figure 5: Coronal MRI of left SOP

Differential diagnosis

The differential diagnosis of SOP includes congenital muscular
torticollis, synostotic plagiocephaly, dissociated vertical deviation
(DVD), double elevator palsy, and ocular tilt reaction. Here are clinical
findings to differentiate SOP from others, but again, coronal MRI is
helpful to confirm SOP.

• Congenital muscular torticollis can be distinguished from
congenital SOP by 1) the examiner’s inability to passively tilt
the head in the opposite direction, 2) the palpation of a tight
sternocleidomastoid muscle on the side of the tilt, 3) the persistence
of the tilt when the infant is reclined, and 4) persistence of the
tilt when either eye is patched. Synostotic plagiocephaly can be
identified with head CT or x-ray.

• DVD may present with hyperdeviation and a contralateral head
tilt, which simulates IOOA with SOP. Differences in SOP and
DVD are 1) elevation is seen in adduction, primary position, and
abduction with DVD, but seen in abduction with SOP, 2) superior
oblique function may be overacting with DVD, but underacting
with SOP; and 3) speed of vertical deviation is slow in DVD, and
rapid in IOOA.

• Double elevator palsy mimics SOP in young children fixating on

CME on COMPLEX STRABISMUS 47

Superior Oblique Palsy

the paretic eye. The long-lasting SOP may produce contracture of
the inferior rectus muscle, limiting the elevation in both abducting
and adducting positions.

• The ocular tilt reaction can be differentiated from SOP by
measuring cyclotorsion. The higher eye shows intorsion and the
lower eye shows extorsion on the double Maddox rod test and
fundus examination, while the higher eye is extorting in SOP
patients.

Treatment

The aim of treatment for SOP are correcting cosmetic appearance,
making ease binocular seeing in patients with congenital SOP and to
reduce diplopia in patients with acquired SOP.

Congenital SOP should be surgically treated, whereas acquired SOP
can be treated either non-surgically or surgically, depending on the
amount of cyclotorsion.

Non-surgical treatment

Although prisms do not correct torsional diplopia, after correcting
horizontal and vertical deviations with prisms, many patients neglect
the torsional component with a large fusional range in torsion. The
power of prisms can be less than the deviation determined by the
alternate prism cover test. Patients with less than 10 prism diopters
of vertical deviation and less than 10 degrees of cyclotorsion are
candidates for prism wearing.

Surgical treatment

Several options are available for the surgical treatment of SOPs. Knapp
classified SOP based on the vertical deviations in nine gaze positions
and proposed surgical options depending on the classification9, as
shown in Figure 6. The surgical procedures included ipsilateral
inferior oblique muscle weakening, SO strengthening, superior rectus
muscle recession, and contralateral inferior rectus muscle recession.
When the vertical deviation is quite small, but the torsional deviation
is large, the anterior part of the SO muscle strengthening (Harada-Ito
procedure) is an option.

48 CME on COMPLEX STRABISMUS

Superior Oblique Palsy

Class I Class II Class III
(27%) (31%) (21%)

Bilateral
Class VI (11%)

Class IV Class V Associated with Brown syndrome
(3%) (6%) Class VII (0.5%)

Figure 6 Knapp classification

When the vertical deviation of the primary position exceeds 15
prism diopters, a single muscle surgery may not be sufficient, and a
combination of the above procedures is recommended.10

The inferior oblique muscle weakening procedure is the most
popular procedure for both congenital and acquired SOPs. The
weakening methods include myectomy, tenotomy, recession, anterior
transposition, and anterior and nasal transposition. Several authors have
reported that anterior transposition and recession are the most effective
weakening procedures; however, postoperative inferior oblique palsy
and anti-elevation syndrome should be considered.11,12 Other authors
emphasizes the inferior oblique disinsertion and myectomy are
equally effective on patients with SOP when their vertical deviation is
less than 15 prism diopters13 and others reported that inferior oblique
muscle myectomy and recession are equally effective.14

Contralateral inferior rectus muscle recession is an option with or
without inferior oblique muscle surgery. Excyclotorsion can be
corrected in addition to vertical deviation when the inferior rectus
muscle is recessed and transposed nasally.15 One muscle-width nasal
transposition can correct 5–8 degrees of cyclotorsion.16 When bilateral
inferior rectus muscle recession with nasal transposition is combined
with bilateral inferior oblique myectomy, it can correct 30 degrees of
excyclotorsion without changing the vertical and horizontal deviations
for bilateral SOP.17

CME on COMPLEX STRABISMUS 49

Superior Oblique Palsy

Details of procedure

• Inferior oblique muscle weakening

The inferior oblique muscle can be identified through the
inferotemporal quadrant conjunctival incision, 7–9 mm from
the limbus. The lateral rectus muscle is secured with a muscle
hook, and the control suture was passed beneath the lateral rectus
muscle. After identifying the inferior oblique muscle, the muscle
hook is placed under direct visualization to avoid injuring the
vortex vein. The inferior oblique muscle is carefully freed from the
surrounding periorbital fat with scissors and is aware of the nearby
vortex vein. When isolating the insertion of the inferior oblique
muscle tendon, the surgeon can perform tenotomy or myectomy.
To perform recession or anterior transposition, the double-armed
suture is passed on the muscle tendon, and the suture is placed on
the planned location of the sclera.

• Superior oblique muscle strengthening

The SO tendon tuck procedure is effective in correcting both
hypertropia and excyclotorsion in patients with SOP. Because
there are anatomical variations of the SO tendon,2 the surgeon
should be familiar with its anatomy and techniques. Before starting
the surgery, a SO tendon traction test should be performed. When
the SO tendon is as tight as the fellow eye, a SO tuck should be
performed minimally or other surgical options should be selected
to avoid postoperative Brown syndrome.

The SO tendon is exposed using a superotemporal conjunctival
incision. The superior rectus muscle is secured and cleaned
carefully to prevent damage to the SO tendon located beneath the
SO muscle. The SO tendon is usually visualized temporal of the
superior rectus muscle attaching to the globe and 7 mm posterior
to the insertion of the superior rectus muscle. After identifying
the whole tendon, a non-absorbable suture is placed to tuck the
SO tendon. The amount of tuck is determined by the SO tendon
traction test. After the tendon is adequately tucked, the traction
test becomes symmetric to the other side.

50 CME on COMPLEX STRABISMUS

Superior Oblique Palsy

• Harada-Ito procedure
The SO tendon is visualized using the SO tendon tuck technique.

The SO tendon is split longitudinally using small Westcott scissors.
A non-absorbable suture is placed on the anterior part of the SO
tendon, detached from the sclera, and then pulled temporally.
Sutures are then placed on the sclera.

Classification of SOP with the variation of SO tendon anomalies

Normal
Class I: Loose tendon easily raised from sclera
Class II: Insertion in sclera nasal to usual
Class III: Thin tendon inserting in Tendon’s
Class IV : Absent tendon

Traction test (surgeon’s view)

Complications

Inferior oblique weakening procedure: Fat adhesion syndrome
and anti-elevation syndrome are common complications. Both
complications entail limitations of supraduction and IOOA of the
fellow eye. Fat adhesion syndrome is very difficult to recover once it
has occurred, and careful maneuver of the fat surrounding the inferior
oblique muscle is important to avoid complications.

CME on COMPLEX STRABISMUS 51

Superior Oblique Palsy

Postoperative limitation of supraduction in adduction (Brown
syndrome) is a common complication of the SO tendon tuck
procedure,18 to avoid which, an intraoperative traction test of the
SO tendon is recommended.19 In cases with a lax SO tendon and
vertical deviation exceeding 15 prism diopters, simultaneous surgery
of inferior oblique muscle and SO tendon tuck procedure with SO
tendon traction test is safe and effective.20 When the SO tendon is
not lax, other procedures, such as contralateral inferior rectus muscle
recession, are recommended.

Conclusion

SOP is a common vertical deviation and surgical treatment is often
required.

Clinical and imaging studies are necessary for differential diagnosis
in complicated cases. Many surgical options have been proposed;
however, randomized controlled studies have not been performed.

References

1. Yang HK, Kim JH, Hwang JM: Congenital superior oblique palsy and trochlear
nerve absence: a clinical and radiological study. Ophthalmology 2012,
119(1):170-177.

2. Helveston EM, Krach D, Plager DA, Ellis FD: A new classification of superior
oblique palsy based on congenital variations in the tendon. Ophthalmology 1992,
99(10):1609-1615.

3. Demer JL, Miller JM: Magnetic resonance imaging of the functional anatomy of
the superior oblique muscle. Invest Ophthalmol Vis Sci 1995, 36(5):906-913.

4. Sato M: Magnetic resonance imaging and tendon anomaly associated with
congenital superior oblique palsy. Am J Ophthalmol 1999, 127(4):379-387.

5. von Noorden GK, Murray E, Wong SY: Superior oblique paralysis. A review of
270 cases. Arch Ophthalmol 1986, 104(12):1771-1776.

6. Parks MM: Isolated cyclovertical muscle palsy. AMA Arch Ophthalmol 1958,
60(6):1027-1035.

7. Souza-Dias C: Asymmetrical bilateral paresis of the superior oblique muscle. J
AAPOS 2007, 11(1):12-16.

8. Manchandia AM, Demer JL: Sensitivity of the three-step test in diagnosis of
superior oblique palsy. J AAPOS 2014, 18(6):567-571.

52 CME on COMPLEX STRABISMUS

Superior Oblique Palsy

9. Knapp P, Moore S: Diagnosis and surgical options in superior oblique surgery.
Int Ophthalmol Clin 1976, 16(3):137-149.

10. Nash DL, Hatt SR, Leske DA, May L, Bothun ED, Mohney BG, Brodsky MC,
Holmes JM: One- versus two-muscle surgery for presumed unilateral fourth
nerve palsy associated with moderate angle hyperdeviations. Am J Ophthalmol
2017, 182:1-7.

11. Jafari K, Gibbings N, Jain S: Inferior oblique overaction in trochlear nerve palsy:
anterior transposition versus myectomy. J AAPOS 2021, 25(1):18.e1-18.e5.

12. Farid MF, Anany M, Abdelshafy M: Surgical outcomes of three different
weakening procedures of inferior oblique muscle in the treatment of unilateral
superior oblique palsy. BMC Ophthalmol 2020, 20(1):298.

13. Aghdam KA, Asadi R, Sanjari MS, Sadeghi A, Razavi M: Comparing two
Inferior Oblique Weakening Procedures: disinsertion versus Myectomy. J
Ophthalmic Vis Res 2021, 16(2):212-218.

14. Rajavi Z, Molazadeh A, Ramezani A, Yaseri M: A randomized clinical trial
comparing myectomy and recession in the management of inferior oblique
muscle overaction. J Pediatr Ophthalmol Strabismus 2011, 48(6):375-380.

15. von Noorden GK, Jenkins RH, Chu MW: Horizontal transposition of the vertical
rectus muscles for cyclotropia. Am J Ophthalmol 1996, 122(3):325-330.

16. Okamoto M, Kimura A, Masuda A, Mimura O: Surgical effects of nasal
transposition of inferior rectus muscle −135 cases of acquired superior oblique
palsy. Clin Ophthalmol 2015, 9:691-695.

17. Komori M, Suzuki H, Iimori H, Hikoya A, Hotta Y, Sato M: Two cases of acquired
bilateral trochlea nerve palsy treated by simultaneous inferior rectus muscle
nasal transposition and inferior oblique muscle myectomy. Am J Ophthalmol
Case Rep 2021, 21:101011.

18. Helveston EM, Mora JS, Lipsky SN, Plager DA, Ellis FD, Sprunger DT, Sondhi
N: Surgical treatment of superior oblique palsy. Trans Am Ophthalmol Soc 1996,
94:315-328; discussion 328-334.

19. Plager DA: Traction testing in superior oblique palsy. J Pediatr Ophthalmol
Strabismus 1990, 27(3):136-140.

20. Komori M, Suzuki H, Hikoya A, Sawada M, Hotta Y, Sato M: Evaluation of
surgical strategy based on the intraoperative superior oblique tendon traction
test. PLOS ONE 2016, 11(12):e0168245.

CME on COMPLEX STRABISMUS 53

Duane Retraction Syndrome 04

Duane Retraction Syndrome

Dr Reena Gupta, Dr Rohan Madan, Dr Chekitaan Singh,
Dr Neebha Anand

Regional Institute of Ophthalmology, PGIMS, Rohtak, 1. Ishwar Eye Centre, Rohtak

Duane retraction syndrome (DRS) also known as Stilling-Turk-
Duane syndrome is a congenital ocular motility disorder characterised
by marked limitation or absence of abduction, variable limitation
of adduction, palpebral fissure narrowing and globe retraction on
attempted adduction.1 Vertical ocular movements; upshoots and
downshoots of the affected eye are often noted on adduction.

Etiopathogenesis

Duane retraction syndrome has been well defined clinically but the
etiopathogenesis of this condition remains unclear. Surgical autopsy
and electromyographic studies have provided insight into pathogenesis
of DRS.

A. Historical Aspects:
Anatomical findings and structural anomalies:
Originally it was believed that Duane retraction syndrome is

a myogenic phenomenon and as explained by Turk2 the first
suspected cause of abduction deficiency and globe retraction
was abnormal tightness of lateral rectus muscle. This functions
as an inelastic band. The limitation of adduction as reported in
literature by Heuck3 is due to a posterior insertion of the medial
rectus muscle. Adhesions between the medial rectus muscle and
medial orbital wall were also reported. Later on Duane advocated
the dual insertion theory of medial rectus as a way of explaining
unusual eye movements in the syndrome.
Autopsy findings:
The histological demonstration of hypoplasia or absence of the

54 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

abducens nucleus and nerve on the affected side, the fibrosis of
the lateral rectus muscle and the hyperplasia of the medial rectus
supports the myogenic view. It was seen that the region of the
lateral rectus muscle that was innervated by fibres from the third
nerve appear to have healthy well-formed muscle bundles. The
remaining muscle mass was poorly innervated and fibrotic.

EMG findings:

Subsequent EMG studies have proven that Duane retraction
syndrome is a neurogenic disorder involving either a supranuclear
lesion or a cranial nerve anomaly in which branches of the
oculomotor nerve were redirected to aberrantly innervate the
lateral rectus muscle resulting in anomalous recruitment of
lateral rectus on intended adduction. Depending on how many
oculomotor nerve fibres normally bound for the medial rectus
muscle get redirected to lateral rectus muscle there maybe
essentially normal or slightly subnormal or remarkably abnormal
action of the medial rectus muscle. It has also explained that the
phenomenon of globe retraction is caused by a co-contraction of
horizontal rectus muscles.

The congenital absence of innervation to the muscles has been
found to cause fibrotic changes in the extraocular muscles
leading to abnormal motility in Duane retraction syndrome, a
concept which has evolved over the last decade to be known as
Congenital cranial dysinnervation disorder. Now it is a part of
Congenital cranial dysinnervation disorders.4 The developmental
abnormalities of cranial nerves cause congenital dysinnervation
of the cranial muscles. This may be primarily due to absence of
normal innervation or secondary following aberrant innervations
from other cranial nerves. Congenital cranial dysinnervation
disorder is a non-progressive entity.

B) Heredity

Genetics also play a major role in development of DRS.The
mutations of the following genes have been reported to be the
major etiological factors.5,6

CME on COMPLEX STRABISMUS 55

Duane Retraction Syndrome

Genes Involved Functions
PHOX2A, HOXA1,
ROBO3 Necessary for growth and maturation of
CHN1 brainstem neurons and axons

SALL4 gene on Its mutations is associated with autosomal
chromosome 20 dominant variant of DRS

Chromosome 7p15.2 Mutation leads to Duane radial ray
of the HOXA gene syndrome, Holt oram, acro-renal-ocular
syndrome

Mutation leads to Bosley–Salih–Alorainy
syndrome (bilateral DRS with inner ear
malformations, cerebrovascular and
cognitive abnormalities)

C. Embryopathy

A common teratogenic stimulus at 8 weeks of gestation can cause
Duane syndrome (Cross and Pfaffenbach). Duane syndrome has
been linked to fetal alcohol syndrome in which there is damage
to developing abducens nuclei. Duane syndrome is also linked to
vascular hypo function during 4th -5th week of embryogenesis.
Duane syndrome is also commonly reported in patients with
thalidomide syndrome thus proving its aetiology to be teratogenic
in nature.7 Hence any maldevelopment or injury to abducens
nerve nucleus during 4th to 8th week8 of gestation would lead to
hypoplasia of the 6th nerve nucleus and result in dysinnervation.

Clinical Features:

Demographic and epidemiological factors:

The prevalence of DRS in general population of strabismus patients
is 1 to 4 %.9 There is a 60% predominance of the syndrome among
females, and it occurs unilaterally, left eye is more frequently involved
and is sporadic in nature (Figure 1) Some cases of familial origin
mostly bilateral with autosomal dominant inheritance pattern have
also been reported.

56 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

Figure 1: Upper row: patient with bilateral EsoDRS
Lower row: Left to right: right ExoDRS; Left ExoDRS with face turn

Refractive error and amblyopia :

Hyperopia is a common refractive error in DRS. DRS with head
turn and small angle esotropia can be corrected with optimal optical
correction. Anisometropic amblyopia is also seen frequently in DRS.

Approach to a case of Duane’s syndrome :

Parents usually approach ophthalmologists after they notice limitation
of abduction, strabismus, or horizontal face turn of varying degree.
Compensatory head positions are frequent and intended to obtain
fusion or attain or maintain fixation when there are imbalanced forces
in the primary zone.

The lid fissure changes, presence of pseudo ptosis on attempted
adduction or cosmetically unacceptable upshoots or downshoots are
other reasons to seek medical attention. Although DRS is present from
birth, it may not be recognisable during infancy as infants may mask
Duane’s syndrome by choosing not to look towards the affected side or
by settling for less than a completely compensatory turn. The infant’s
near world and examiners arm length examination compensate for
some esodeviations that may exist. The lid fissure changes usually
appear with the progressive development of more severe mechanical
changes and hence are not seen during infancy.

We should inspect and evaluate for presence of microcephaly, pre-
auricular tags, pinna defects, deafness, cleft palate, facial asymmetry.
Systemic examination should be done to rule out cardiac anomalies,
limb deformities, phocomelia, vertebral anomalies, spina bifida, renal
dysplasia with vesicoureteral reflux and imperforate anus.

One should be alert to the developmental syndromes that have a

CME on COMPLEX STRABISMUS 57

Duane Retraction Syndrome

similar time course for development. Syndromes like Moebius
syndrome, Goldenhaar syndrome, CFEOM gaze palsy may merge into
one another or present in combinations with DRS.

Associated Anomalies with DRS

DRS is associated with many congenital anomalies that are ocular as
well as non-ocular in nature. These are listed as follows:

Associated Syndromes:10 Non Occular Associations
Goldenhar syndrome
Pinna defects, deafness,
Klippel-feil syndrome preauricular tags
Holt-Oram Wildervanck
syndrome Cleft palate, facia asymmetry
Fetal alcohol syndrome
Arthrogyropsis multiplex, Cardiac anomalies, limb
congenital oculocutaneous deformities, phocomelia
albinism
Microcephaly

vertebral anomalies, spina bifida,
renal dysplasia, imperforate anus

Sensory evaluation:
DRS patients usually have normal binocularity in a preferred fusing
position despite the incomitance.

Ocular deviations:
The cover test for measuring ocular deviation is performed in habitual
head position and in forced straight-ahead primary position and then
with either eye fixing and for near and distance and in different gazes.

A limitation of cover test is poor abducting saccade of the DRS eye
during cover test, making it less accurate. A simple alternative way
is to force fixation with Duane’s eye and to place prisms in front of
it with the fellow normal eye observable under partial cover. The
fixation duress drives the fellow eye in or out until it is neutralised by
appropriate prisms in front of the Duane’s eye.11

Ocular movements:
Ocular rotations form the cornerstone of the diagnosis and differential

58 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

diagnosis. The examiner must look for any normal or subnormal lateral
rectus activity in horizontal plane. Note for the amount of anomalous
LR innervation in up, down or opposite horizontal gaze.

Presence of upshoots and downshoots:

The characteristic vertical movements of over elevation or depression
on attempted adduction are noted only in severe anomalous
innervation of lateral rectus. About 25 to 39% of the patients present
with upshoots and down shoots in adduction. The mechanism of these
vertical eye movements can be mechanical or innervational or both. In
the mechanical type, overshoot occurs abruptly as the eye moves into
adduction. The mechanical type of upshoot and down shoot is due to
tight lateral rectus attached to the crest of the globe which causes the
muscle to slip over the globe when the eye is adducting and is termed
as the ‘bridle effect’. In the innervational type of overshoot, there is
a gradual increasing upshoot or down shoot in horizontal position as
it moves into adduction. This is due to co-innervation of vertical or
oblique muscles with the lateral rectus muscle or due to SR contracture.
Vertical deviation in the primary position is not commonly seen in
mechanical type and if it exists; is usually small angle. In contrast,
there is a typically large vertical deviation in primary position in
patients with innervational overshoot. The mechanical upshoot and
down shoot can occur simultaneously in some patients but in the
innervational type, only one of the upshoot or downshoot can occur.12

Grading of Overshoots13

Grading of overshoots is done, with the involved eye in adduction, and
a straight line parallel to the intermedial canthal line is drawn from the
pupillary centre of the fellow eye.
• Grade 0: Line bisects the pupil of the involved eye
• Grade 1: Line lies between the pupillary centre and the pupillary

margin
• Grade 2: Line lies between the pupillary margin and the limbus
• Grade 3: Line lies at the limbus or over the sclera
• Grade 4: Cornea disappears below the lid (pumpkin seed sign).

(Figure 2)

CME on COMPLEX STRABISMUS 59

Duane Retraction Syndrome

Figure 2: left to right: Patient with right ExoDRS; grade 4 upshoot (pumpkin seed
sign); grade 4 globe retraction on attempted adduction.

Globe retraction:
Lid fissure narrowing in opposite gaze accompanies globe retraction.
Most reliable way to see is by manually spreading the lids apart and
look for globe retraction from the side or below.

Grading of Globe Retraction13

With the involved eye in maximum adduction, a scale is used at the
centre of the palpebral fissure to measure the height and compare it
with the fellow eye in abduction. (Figure 3)
Grade 0: No narrowing
Grade 1: <25%
Grade 2: 25%– <50% (Figure 3)
Grade 3: 50%–<75%
Grade 4: ≥75%.

Figure 3: Right exoDRS with both abduction and adduction limitation with grade 3
globe retraction

Patterns:
Three major patterns have been identified with DRS that is V pattern,
Y pattern and lambda pattern. The V pattern is more common but
patients with bilateral DRS tend to have A pattern more frequently.
Y pattern is depicted only from primary gaze to upgaze, owing to
lateral rectus anomalous innervation in vertical gaze. Opposite is true
for lambda pattern (Figure 4) wherein there is increase in exodeviation
on movement from primary to down gaze.

60 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

Figure 4: The angle of deviation classically increases from primary to downgaze
showing lambda patten.

Forced duction test: Forced traction of lateral rectus in opposite
gaze measures both anomalous innervation and mechanical restricting
forces. It could be either absolute or moderate or minimum restriction.
Uniform restriction is the one that increases progressively on increasing
passive rotation. FDT is done to look for tightness of LR and MR
muscles. In DRS, while performing FDT, ask the patient to fixate in
abduction and now as the globe is rotated into adduction passively,
the aberrant firing due to anomalous innervation is absent and we can
gauge the restrictive component of DRS.

Force generation test: The force generation test, which was first
proposed by Scott, is a sensitive measure that may be used to determine
actively innervated abducting force of LR which can be observed or
felt during forceps force generation when the eye actively abducts
from its position whether eso, exo or Ortho.

Force degeneration test : This is an innovative new forceps force
test described by Romero-Apis to demonstrate lateral rectus (LR)
anomalous innervation in opposite gaze in selected cases in which
differential diagnosis need clarification. The patient is asked to look

CME on COMPLEX STRABISMUS 61

Duane Retraction Syndrome

halfway between the primary position and adduction. Then we try to
move the eye into further adduction, and we feel positiveness since
the lateral rectus co-contraction causes some restriction. We ask the
patient to gaze midway between the primary position and adduction,
then we hold the eye with forceps, but now we ask the patient to gaze
outwards, and we sense negativeness (release of force) and we can now
rotate the eye still further inwards, because the lateral rectus has been
inhibited by its IIIrd nerve aberrant innervation. The test establishes
whether or not there is abnormal LR innervation in the opposite gaze.

Clinical presentation:
Most patients with DRS appear to have strabismus in the primary
position. Patients may adopt relatively small unnoticed head positions
which may obscure a small angle strabismus in primary gaze.

The various clinical patterns in DRS are caused by lateral rectus
anomalous innervation in up, down or opposite horizontal gaze and
mechanics with secondary muscle changes such as superior rectus
contracture as a result of severe upshoots and secondary medial
rectus contracture that may result from large degree esotropic Duane
syndrome or medial rectus maybe elongated in large degree exotropic
Duane syndrome. Muscles other than lateral rectus are not innervated
anomalously and rarely medial rectus may have deficient innervation.

Unilateral patterns:
yy Esotropia is the most commonly diagnosed type of strabismus.

Classic EsoDRS14 with absent or reduced or normal lateral rectus
function, anomalous lateral rectus innervation which may exist
alone or in any of the three gaze combinations of up, down or
opposite horizontal gaze with significant upshoots or down shoots
in opposite gaze. (Figure:5 )

Figure 5 : 11-year-old girl presented with Eso DRS, 1. moderate globe retraction
on adduction, 2. Left eso DRS in primary position, 3. Abduction limitation on
laevoversion.

62 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

yy Many patients with DRS are orthophoric in primary position. They
present with relatively immobile globe in primary zone, marked
globe retraction with upshoots/ down shoots.

yy Exodeviation with or without upshoots or downshoots with globe
retraction.

yy Simultaneous abduction of each eye known as the splits with no
retraction or equivalents.

yy Y or lambda pattern with normal or slightly deficient abduction
with no retraction. Anomalous lateral rectus innervation only in
up gaze or down gaze.

yy Fixation with DS eye with marked overshoot or undershoot of the
fellow eye

Bilateral patterns:
yy Of the total; only 15% to 20% are bilateral DRS and most present

as one of the following patterns.

yy Bilateral DS with fusion: they have limited eye movements and/
or relatively immobile globes. Retraction and/or equivalents are
generally not observed.

yy Bilateral DS without fusion: usually present with marked
esodeviations (Figure 10) or marked exodeviations(including
splits). Retraction and/or equivalents are generally not observed.

Classification of DRS:15,16,17,18

Classification Classification
System

Papst- 1. MR and LR
According to 2. Superior rectus and LR
abnormal co- 3. Inferior rectus and LR
contraction 4. LR and other muscles

Malbran- Type I: Palsy of abduction
according to Type II: Palsy of adduction
motility Type III: Limitation of depression and elevation
without impairment of horizontal movements

CME on COMPLEX STRABISMUS 63

Duane Retraction Syndrome

Lyle and Type A: Abduction more deficient than adduction,
Bridgeman- but both are deficient. Adduction causes globe
According to retraction and palpebral fissure narrowing
motility
Type B: Abduction is deficient, but not adduction
Huber-
according to Type C: Abduction less deficient than adduction,
EMG (1974) but both are deficient. Adduction causes globe
retraction and palpebral fissure narrowing

Type I (70%–80%): Marked limitation of
abduction with minimally defective or normal
adduction, globe retraction and palpebral fissure
narrowing in adduction, widening in abduction.
EMG recordings showed paradoxical innervations
of the LR with maximum impulses on adduction
and defective impulses in attempted abduction.
MR was found to have normal electric behaviour.
(Figure 7)

Type II (7%): Marked limitation of adduction with
primary position exotropia of the affected eye,
abduction normal or slightly limited with globe
retraction and palpebral fissure narrowing in at-
tempted adduction On EMG, LR showed peak
impulses on abduction and a second paradoxical
impulse on attempted adduction, while the electri-
cal activity of MR was normal. (Figure 8)

Type III (15%): Limitation or complete
absence of adduction and abduction with globe
retraction and palpebral fissure narrowing in
attempted adduction. EMG showed simultaneous
innervation of LR and MR muscles in primary
gaze, adduction and abduction. Huber also went
on to describe the alphabet patterns of strabismus,
which are also seen in DRS, suggesting that there
are groups of patients wherein the vertical rectus
has this synergistic innervation. (Figure 9)

64 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

Ahluwalia et Included the deviation in primary position in each
al: (1988) of the three groups.

Type 1A: Abduction deficiency with esotropia in
primary position.(more nerve fibres supply the MR
muscle)

Type 1B: Abduction deficiency with exotropia in
primary position (more nerve fibres supply LR)

Type 1C: Abduction deficiency with Orthophoria
in primary position (equal distribution of nerve
fibres maintaining eye in Orthotropic position)

Although multiple classifications of Duane’s retraction syndrome
are present, the one by Huber is the one widely accepted and
most useful clinically and is also supported by electromyographic
documentation.

Figure 7: Patient presenting with Unilateral left classic eso DRS- (type 1 ), Mild
globe retraction on adduction and Limitation of abduction in left eye

Figure 8: Patient presenting with Right ExoDRS-TYPE II, Widening of palpebral
fissure on abduction and Pseudoptosis of right eye on adduction with limitation of

adduction

Figure 9 : Patient presenting with unilateral left Eso DRS type 3; abduction
limitation in left eye and Adduction limitation in left eye with upshoot on adduction

with minimal globe retraction

CME on COMPLEX STRABISMUS 65

Duane Retraction Syndrome

Figure 10: The prevalence of bilateral disease is less; this is a case of Bilateral DRS
presenting with esotropia In primary position with Bilateral abduction limitation and

moderate globe retraction

Differential Diagnosis

1. Congenital abducens paralysis: The following clues can help
distinguish between esotropic DRS and congenital sixth nerve
palsy: 1) DRS patients have globe retraction and lid fissure changes,
upshoots and downshoots in adduction, whereas sixth nerve palsy
patients do not; 2) the esotropic angle is usually smaller in DRS
patients compared to sixth nerve palsy patients with the same
abduction limitation; and 3) the amount of abduction deficit varies
in upgaze and downgaze in DRS patients, whereas it is similar
in sixth nerve palsy patients.19 4) Patients with abducens nerve
palsy have normal adduction and preservation of convergence. In
infancy it is quite difficult to differentiate the two. The clinical
assessment that the angle of deviation in primary position is small
for the amount of limitation in abduction in DRS helps to diagnose
DRS. (Figure 11 and 12)

Figure 11: Congenital abducens nerve palsy

Figure 12: Abduction limitation without lid fissure changes

2. Essential infantile esotropia: it can be differentiated from DRS
as children with infantile esotropia have apparent abduction
deficit and esotropia and so mimics esoDRS but true abduction
deficit can be differentiated by Doll’s head manoeuvre and angle
of deviation is much larger in infantile esotropia. (Figure 13 and

66 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

14) Cross fixation and abduction saccades are usually present in
infantile esotropia and not in DRS.

Figure 13: infantile esotropia with apparent abduction limitation

Figure 14: case of Infantile esotropia with apparent abduction limitation which
could be differentiated from true limitation by testing for ductions.

3. Mobius syndrome: Mobius syndrome is characterised by sixth
and seventh cranial nerve palsy. Also they have limitation of
abduction and adduction and also systemic features like mask like
facies, abnormalities of the limb, bifid tongue, drooling of saliva,
feeding and speech difficulties and also there is absence of fissure
changes and globe retraction, hence differentiating it from DRS.
(Figure 15)

Figure 15: Mobius syndrome: patient with bifid tongue, lagophthalmos and limited
abduction

4. Congenital motor apraxia: These children have impairment
of horizontal gaze and may mimic a bilateral DRS. They can be
distinguished by their characteristic jerky horizontal head thrusts
and eye movements, on the other hand, are fully retained, and with
time, they improve gradually.

Management

yy Non-surgical DRS treatment include glasses or contact lenses to
correct refractive errors, prisms to improve compensatory head
position, and standard treatments for amblyopia. The effectiveness

CME on COMPLEX STRABISMUS 67

Duane Retraction Syndrome

of botulinum toxin has also been studied. The results of the
injection are relative and short-term.20

yy The goal of surgery in DRS are as follows:
1. Significant ocular deviation in primary position,
2. Marked anomalous head posture
3. Severe retraction of the globe on attempted adduction, and
4. Disfiguring upshoots and downshoots on adduction.
Relative indications include:
a) Improvement in the movement of abduction in affected eye
b) To enlarge the binocular diplopia free field

yy Patients have to be explained that no remedy or surgical operation
will bring back normal ocular movements in all gaze positions,
because the basic underlying abnormality of paradoxical
innervation cannot be corrected. Also consent should be taken for
need of second surgery in future. In addition, a Forced duction
Test (FDT) is required prior to surgery for a DRS case to rule out
an MR or LR contracture in the affected eye.21

Surgical Management of EsoDRS

Clinically esoDRS cases do not have normal lateral rectus function but
anomalous lateral rectus recruitment maybe seen in adduction. These
patients have esodeviation in primary position and hence assume a
corrective face turn.

Before planning any procedure it is imperative to check for presence
of contracture of MR by performing FDT. If FDT is positive, tight
medial rectus should always be recessed. MR recession successfully
eliminates abnormal head position and improves deviation in the
primary position. Unilateral MR recession is recommended for
deviations less than 20 PD,22 the amount of recession depends on the
preoperative angle of deviation in the primary position, the degree of
restriction on forced duction test, and the limitations noted on versions
and ductions. In patients with minimal anomalous lateral rectus
activity and normal direct lateral rectus abducting force, a small MR
recession in the affected eye might suffice. Medial rectus recession of
the Duane’s eye should not be more than 5 to 6 mm because of risk
of inducing adduction limitation. Limitation of adduction can induce

68 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

exotropia in the contralateral gaze which can cause intractable diplopia
and it also compromises the field of binocular single vision. There is
also risk of gradual recurrence of deviation and return of abnormal
head position due to lack of abduction tone.

Bilateral MR Recession

Bilateral medial rectus recession has been recommended in unilateral
DRS with more than 20 PD esotropia.

Esotropia without globe retraction: In patients without severe
globe retraction and when eso deviation is large and medial rectus is
minimally tight on FDT, Jampolsky proposed asymmetric recession
of the medial rectus of both eyes with more on the unaffected side. This
large MR recession in unaffected eye produces fixation duress which
prevents contracture of medial rectus in the affected eye. Asymmetric
bilateral medial rectus recessions have reported in improvement of
deviation, abnormal head position, and globe retraction in patients
with unilateral esotropic DRS. (Figure 16)

Figure 16: Upper row: Large angle esotropia in left eye treated by asymmetric
bilateral medial rectus recession.

Lower row: post-surgery: orthotropic in primary position without any improvement
in abduction limitation

Esotropia with globe retraction: in patients with esoDRS with
severe globe retraction, the recession of medial and lateral rectus
muscles of the ipsilateral eye is done with addition of medial rectus
recession of the unaffected eye. For correction of residual deviation
in patients with limited adduction, recession of contralateral medial
rectus can be done for decreasing the amount of ipsilateral medial
rectus recession. Another alternative procedure is posterior fixation
suture of contralateral medial rectus of normal eye. In presence of

CME on COMPLEX STRABISMUS 69

Duane Retraction Syndrome

significant upshoots and downshoots, Lateral rectus bifurcation (Y
split procedure) with recession is effective. In this procedure, the
lateral rectus muscle is split from its insertion as far posteriorly as
possible, spreading the muscle halves up to 10 mm up and 10 mm
down (20 mm between them). Each half of the transposed split muscle
must be recessed a few millimetres (3 to 5 mm) just to compensate for
the resection effect (Figure 17).

Figure 17: Left eye MR recession 8mm with Y split and right eye MR recession
5 mm done in a case of Left esoDRS with upshoot with globe retraction.

Transposition Surgery

Abduction deficit can be tackled by transposition procedures like
SRT/VRT to LR, if there is no significant anomalous LR recruitment
causing co-contraction. If medial rectus is not tight and co-contraction
is minimal, then the transposition procedure- either SRT or VRT can
be done.
Vertical rectus transposition – This procedure has the advantages
of increased abduction ability 10 to 15°; diplopia free visual field;
decreased risk of creating a limitation to adduction. There is a
significant reduction in the need to weaken the ipsilateral medial
rectus muscle. This procedure can be augmented by applying posterior
fixation sutures.
Disadvantages of VRT: Cannot be done in patients of globe retraction;
upshoots and down shoots.

70 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

The main risk factor for residual esotropia after VRT is restriction of
medial rectus muscle. If forced duction test is positive i.e demonstrates
significant restriction to abduction then medial rectus muscle should
be recessed. In such cases either medial rectus recession has to be
done as a secondary procedure or partial VRT can be done along with
ipsilateral medial rectus recession as a primary procedure to avoid risk
of anterior segment ischemia.

Currently the latest technique of SRT that was proposed by Johnston and
colleagues in 200623 allows the option of simultaneous medial rectus
recession in patients with tight medial rectus who need transposition
surgery. The technique may induce some vertical deviation in primary
position though the risk for torsional diplopia is quite low.

If esotropia is less than 15 PD then SRT alone maybe adequate but for
larger deviations, SRT should be combined with MR recession (Figure
18)

When compared to partial VRT, SRT has increased risk of inducing
vertical deviations and torsion. SRT can be done safely in cases with
pre-operative hypertropia and partial VRT in cases of no pre-operative
vertical deviations.

Figure 18: Upper row: Patient with left eye esoDRS with minimal globe retraction
and -4 abduction limitation with tight MR– underwent left MR recession
with Superior rectus transposition.
Lower row: Post surgery hypertropia induced in left eye.

Lateral rectus resection should never be done in the involved eye
though it has been described in the literature; owing to risk of severely
limiting adduction and worsening globe retraction on adduction.

CME on COMPLEX STRABISMUS 71

Duane Retraction Syndrome

ExoDRS

ExoDRS patients present with a primary position exotropia and may
have significant upshoots or down shoots with globe retraction on
adduction. The lateral rectus may be anomalous or both anomalous
and subnormal but more commonly lateral rectus is severely
anomalous with contracture in ExoDRS. So the surgical goal is to
correct the deviation and head turn and ameliorate as much of the
anomalous DRS eye movement as possible. For such patients, lateral
rectus recession with Y split (Figure 19) or supra maximal lateral
rectus recession or periosteal fixation of lateral rectus can be done.
In patients with exodeviation less than 20 PD - a unilateral lateral
rectus recession and for patients with more than 20 PD exodeviation-
bilateral lateral rectus recession with surgical dosage more than the
standard nomograms is done. (Figure 20) (1mm recession for 1 Prism
dioptre of primary position exodeviation correction)

Figure 19: Upper row: type II exo DRS- in primary position with grade 4 upshoot
and severe globe retraction, underwent right LR recession 10mm with Y split.
Lower row: complete resolution of globe retraction, upshoot and attained full
right adduction.

Figure 20: Upper row: patient had a large angle exoDRS in the left eye with globe
retraction and abduction limitation- underwent a bilateral LR recession (right 13mm

and left 14mm) with a Y split.
Lower row: improvement in upshoot, and globe retraction and face turn

72 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

Recession of the tight and shortened lateral rectus can correct the
deviation and face turn and simultaneously reduce the upshoots and
globe retraction at the cost of increased abduction limitation. If globe
retraction is severe; then profound weakening of lateral rectus muscle –
LR periosteal fixation maybe needed. This can be combined with VRT.

The other approach for these patients is simultaneous recession of
ipsilateral lateral rectus and medial rectus muscles. (Figure 21) If
globe retraction is minimal and there is residual exotropia then VRT
towards MR can also be done to improve adduction with augmentation
suture and resection of superior rectus and inferior rectus muscles.

Figure 21: Upper row: patient with exoDRS with right hypertropia with marked
globe retraction and upshoot, underwent MR recession 4.5mm ad LR recession

11mm with Y split
Lower row: Showed improvement in globe retraction and upshoot.

Sometimes anomalous orbital structures like bands may attach to the
globe and restrict mobility. FDT will not be free until these bands
are dissected out and released. Both retraction and overshoot improve
when LR recession and Y split are done simultaneously.

The innervational type of overshoot can be improved with the recession
of the appropriate vertical rectus muscle. (Figure 20).

ORTHO-DRS

These patients present with globe retraction, narrowing of palpebral
aperture and upshoots or down shoots on adduction which may be
cosmetically very disfiguring; surgical intervention can lead to a
consecutive heterotropia so should be managed by equitable recession
of both lateral rectus and medial rectus in the affected eye with the use

CME on COMPLEX STRABISMUS 73

Duane Retraction Syndrome

of adjustable surgery on medial rectus and Y split on lateral rectus to
control the risk of under and over corrections.

Bilateral Duane’s Retraction Syndrome

Bilateral DRS is seen in 15 to 20% of cases and most of them are either
esoDRS or orthoDRS. Bilateral eso can be managed by bilateral MR
recessions as per FDT and one medial rectus on adjustable preferably.
Bilateral exoDRS is managed by bilateral lateral rectus recession and
Y split can be added in cases of marked upshoots.

Bilateral DS with Fusion

Bilateral cases can be associated with fusion; such cases have small
or no deviation in primary position, with relatively immobile globes,
often without a retraction. Surgery can be unpredictable in these
patients and prisms can be prescribed if needed.

Bilateral DS with Fusion

Patients have noticeable deviation and abnormal head position, marked
esodeviations or exodeviations; sometimes patients with fusion may
also be compensated with increasing deviation. Bilateral horizontal
muscle recession has proven to improve abnormal head position and
correct strabismus in primary position

Simultaneous Abduction

Also known as synergistic divergence or splits or type 4 DRS are
synonyms for the condition that is characterised by outward rotation
of the Duane eye as the normal fixing eye goes into abduction. Patients
usually have exotropia, face turns towards the unaffected eye and
absent or decreased adduction of involved eye. Weakness of medial
rectus is responsible for this type of DRS, it can occur congenitally due
to misrouting of third nerve to the lateral rectus, causing the medial
rectus to be deprived of its usual amount of innervation. The surgical
procedure of choice is weakening of the ipsilateral lateral rectus
muscle along with medial rectus resection. It can be done as there
is no globe retraction. This usually correct abnormal head position,
deviation and simultaneous abduction.

74 CME on COMPLEX STRABISMUS

Duane Retraction Syndrome

Summary

The syndrome of Duane's retraction (DRS) is a common cause of
abnormal head position. DRS is a clinical ocular condition characterised
by globe retraction with lid fissure narrowing during attempted
adduction, frequent abduction deficiency with varying adduction
limitation, and upshoot and/or downshoot of the affected eye during
adduction. Now known as co–contractive retraction syndrome, it is
a subset of congenital cranial dysinnervation illnesses that includes
Moebius syndrome and congenital fibrosis of extraocular muscles.
Anomalous or subnormal LR innervations and mechanical changes
account for the DRS patterns. Secondary changes of not anomalously
innervated muscles may also occur.

Management usually involves recession procedures of culprit muscle
but there is no strict and single procedure for DRS and is individualised
according to each case based on the clinical features it presents with.
With advancement in the surgical techniques and imaging modalities,
optimal surgical outcome for Duane’s syndrome can be achieved.

References

1. DeRespinis P, Caputo A, Wagner R, Guo S. Duane’s retraction syndrome. Surv
Ophthalmol. 1993;38(3):257–288

2. Turk S. Comments to a case of retraction of the eye. Cbl Pract Augenheilk
1899;23:14.

3. Heuck G.Uber angenborenen vertebren Beweglichkeitsdefect derAugen.Klin
Monatsbl Augenheikd 17:253.1879.

4. Assaf AA. Congenital innervation dysgenesis syndrome (CID)/congenital
cranial dysinnervation disorders (CCDDs). Eye. 2011;25(10): 1251–1261.

5. Nakano M, Yamada K, Fain J, et al. Homozygous mutations in ARIX(PHOX2A)
result in congenital fibrosis of the extraocular muscles type 2. Nat Genet.
2001;29(3):315–320.

6. Tischfield MA, Bosley TM, Salih MA, et al. Homozygous HOXA1 mutations
disrupt human brainstem, inner ear, cardiovascular and cognitive development.
Nat Genet. 2005;37(10):1035–1037.

7. Miller M: Thalidomide embryopathy: A model for the study of congenital
incomitant horizontal strabismus.Trans Am Ophthalmol Soc 89:6323, 1991.

8. Hoyt WF, Nachtigäller H. Anomalies of ocular motor nerves. Neuroanatomic

CME on COMPLEX STRABISMUS 75

Duane Retraction Syndrome

correlates of paradoxical innervation in Duane’s syndrome and related congenital
ocular motor disorders. Am J Ophthalmol 1965;60:443‐8.

9. Gurwoods AS, Terrigno CA. Duane’s retraction syndrome: literature review.
Optometry. 2000;71(11):722–776.

10. Jayakumar M, Prashanthi B. Duane retraction syndrome: Clinical presentation
and management strategy. TNOA Journal of Ophthalmic Science and Research.
2019;57(1):49.

11. Chung M, Stout JT, Borchert MS. Clinical diversity of hereditary Duane’s
retraction syndrome. Ophthalmology. 2000;107(3):500–503.

12. Kekunnaya R, Gupta A, Sachdeva V, et al. Duane retraction syndrome: series of
441 cases. J Pediatr Ophthalmol Strabismus. 2012;49(3):164–169

13. Kivlin JD, Lunderman MK. Acquired Retraction syndrome associated with
orbital metastasis. J Pediatr Ophthalmol Strabismus. 1985;22(3):109–112.

14. Kekunnaya R, Velez FG, Pineles SL. Outcomes in patients with esotropic
duane retraction syndrome and a partially accommodative component. Indian J
Ophthalmol. 2013;61(12):701–4.

15. Huber A. Electrophysiology of the retraction syndromes. Br J Ophthalmol.
1974;58(3):293–300.

16. Dawson E, Maino A, Lee J. Diagnostic Use of Botulinum Toxin in Patients with
Duane Syndrome. 2021.

17. Sharma P, Gaur N. Management of Duane retraction syndrome: A simplified
approach. 2021.

18. Kekunnaya R, Kraft S, Rao V, Velez F, Sachdeva V, Hunter D. Surgical
management of strabismus in Duane retraction syndrome. 2021.

19. Kasturi N, Congenital sixth nerve palsy with associated anomalies. Indian
journal of ophthalmology. 2017

20. Dawson E, Maino A, Lee J. Diagnostic use of botulinum toxin in patients with
duane syndrome. 2021

21. Sharma P, Gaur N. Management of Duane Retraction Syndrome: A simplified
approach. 2021

22. Kekunnaya R, Negalur M. Duane retraction syndrome: causes, effects and
management strategies. Clinical Ophthalmology. 2017;Volume 11:1917-1930.

23. Mehendale RA, Dagi LR, Wu C, Ledoux D, Johnston S, Hunter DG. Superior
rectus transposition and medial rectus recession for Duane syndrome and
sixth nerve palsy. Arch Ophthalmol. 2012;130(2):195-201. doi:10.1001/
archophthalmol.2011.384

76 CME on COMPLEX STRABISMUS

05Dissociated Vertical Deviation

Dissociated Vertical
Deviation

Dr. Andrea Molinari, MD

Hospital Metropolitano, Quito - Ecuador

Introduction

Dissociated vertical deviation (DVD) is an intermittent deviation of
the nonfixing eye that moves upward, lateral and excyclotorts. This
deviation is different from a conventional vertical deviation because
the fellow eye does not exhibit refixation movement in the opposite
direction.1 The deviation can occur spontaneously, especially when
the patient is inattentive, daydreaming or in a testing situation when
binocular vision is broken by occluding one eye.(Figure. 1)

Figure 1: Note the upward deviation of the left covered eye

This anomalous movement has three components: the first an upward
movement, and when this vertical movement is predominant, it is called
“Dissociated vertical deviation”. Second, a horizontal component and
when this is the most noticeable one, then it is known as “Dissociated
horizontal deviation”. The third is when very unusually, only the
torsional component is noticed and then it is called “Dissociated

CME on COMPLEX STRABISMUS 77

Dissociated Vertical Deviation

torsional deviation.” “Dissociated strabismus complex” is a more
inclusive term for this entity.2,3 Different components of this entity can
be recognized in the same patient. (Figure. 2)

Figure 2: Patient exhibiting a predominant vertical component on the right eye and
a predominant horizontal component on the left eye.

Since its first report by Stevens, described as alternating vertical
strabismus,4 dissociated vertical strabismus has been described
under many different names1 but without doubt the most popular
one is dissociated vertical deviation (DVD) as proposed by Alfred
Bielschowsky.5
Dissociated vertical deviation is still one of the most mysterious forms
of strabismus. Many theories have been proposed trying to explain
what causes DVD. Current concepts focus on either a supranuclear
disorder,1 the appearance of an atavistic subcortical reflex6 or mediated
by the oblique muscles trying to dampen a latent nystagmus.7,8

Incidence

DVD can appear with different forms of strabismus including sensory
deviations, exotropia and congenital esotropia.
Without doubt the most frequent association is with congenital
esotropia. Different authors claim an association between congenital
Esotropia and DVD with ranges between 14 and 90%. This makes
DVD a marker for Congenital Esotropia.9 (Figure. 3)
More rarely DVD can occur as an isolated finding.

78 CME on COMPLEX STRABISMUS

Dissociated Vertical Deviation

AB C

Figure. 3 Patient with congenital esotropia A: before surgery. B: one month after
surgery C: one year after surgery develops a decompensated DVD

Clinical Features

Dissociated vertical deviation has specific clinical features. Among
them are:
yy Mixed, vertical, horizontal and torsional eye movement that

occurs in the non-fixing eye in a tired or inattentive patient or
after covering one eye.

yy The fellow eye does not exhibit refixation movement in the
opposite vertical direction although it does show a simultaneous
incyclorotatory movement.

yy Usually intermittent and manifesting with a variable magnitude.

yy Latent nystagmus with a horizontal and cyclovertical component
is present in approximately half of the cases.1

yy Usually bilateral and asymmetrical.

yy Unilateral cases are usually encountered in deeply amblyopic
eyes.

yy It is a slow movement and variable in speed.

yy DVD can have a tropic and a phoric phase.

yy It can be associated with concomitant non dissociated vertical
strabismus.

yy Horizontal incomitance can be present, especially when associated
with oblique muscle dysfunction. If not associated with oblique
dysfunction it can be larger in abduction.

CME on COMPLEX STRABISMUS 79

Dissociated Vertical Deviation

yy Measurements can be variable which can make clinical
quantification difficult.

yy Anomalous Head posture can be present as a Head turn or a Head
tilt and can contribute to control the DVD.10 When the head is
tilted towards the shoulder of the fixing eye it is called direct tilt
and when tilted towards the shoulder of the non-fixing eye it is
called inverse tilt.

yy DVD is more manifest in distance than in near fixation.11
yy Fusion is usually poor, and suppression can be present.12
yy It can present before 12 months of age but it is more commonly

noticed after the first year of life.13 Many times, it is first noticeable
once the surgery for congenital esotropia has been performed.
(Figure. 3)

Diagnosis

For the careful and experienced examiner, DVD should be easy to
recognize. The presence of a slow vertical upward deviation without
an opposite direction refixation movement in the fellow eye in an
inattentive or fatigued patient is pathognomonic for a DVD.

Assessing the magnitude of the DVD is best done with the cover
under cover test evaluating each eye separately. The eye to be tested is
covered and a base-down prism is placed between the occluder and the
eye. The occluder is left for at least 5 to 10 seconds in order to allow
the maximum deviation to occur. The occluder is then moved to the
fixing eye and the movement (or lack of movement) of the measured
eye is recorded. The power of the base-down prism is increased until
no further downward movement is detected.

When DVD is associated with a horizontal deviation it is recommended
to measure the larger deviation first.2

There are several diagnostic tests that can be useful to confirm this
diagnosis:

The reversed fixation test, although originally described to detect small
DVDs by Mattheus and coauthors, it is more useful to diagnose DHD.

80 CME on COMPLEX STRABISMUS

Dissociated Vertical Deviation

This test simply identifies the presence of a dissociated component in
the deviation.14

How is this test performed? When examining a left exo DHD, the test
starts with a conventional prism and alternate cover test neutralizing
the deviation with a prism. With the prism over the left eye, shift
the occluder to the right eye and make sure there is no movement
on the left eye under the prism. After the patient fixates through the
prism with the left eye for at least 5 seconds, shift the occluder back
to the left eye. No refixation present on the right eye means the test
is negative and there is no dissociated component. If a movement of
refixation is seen on the right eye, this means the test is positive and
this is a dissociated deviation.2

When performing the red glass test in patients with DVD, the patient
always refers seeing the red image below the white image no matter
in which eye the red glass is placed. In patients with non-dissociated
vertical deviation the red image is seen below the white image when
the red glass is placed in front of the hypertropic eye and above the
white image when it is placed in front of the hypotropic eye.15

The Bielschowsky phenomenon, characteristically present in DVD is
done by placing a filter bar over the fixing eye. When shifting the bar
up placing denser filters over the fixing eye, a downward movement of
the eye presenting the DVD can be observed.16

The Posner maneuver, described by Posner in 194416 and popularized
by Olivares-Medina and Arroyo Yllanes17 is also useful to confirm a
diagnosis of DVD. In this test one eye is occluded with a translucent
occluder and elevation of the occluded eye is observed. Then, the other
eye is occluded with a second translucent occluder and depression of
the first eye is observed.

In the diagnosis of DVD, several characteristics must be considered to
plan for the most appropriate surgery.

1) Visual Acuity of each eye

2) Magnitude of the deviation

3) Symmetry of the deviation

CME on COMPLEX STRABISMUS 81

Dissociated Vertical Deviation

4) Presence of concomitant non dissociated vertical deviation.

5) Horizontal Incommitancy

6) Presence of other dissociated deviations that ideally should be
recognized and addressed in the same surgical setting as the
vertical deviation

7) Horizontal Incommitancy

8) Presence of other dissociated deviations that ideally should be
recognized and addressed in the same surgical setting as the
vertical deviation

Determining Visual Acuity is crucial when deciding if a unilateral
procedure will be suitable for a very asymmetric case. Bilateral
surgery is always the best option unless there is reason to believe that
the non-fixing eye will never become preferred for fixation.

To establish a surgical plan for DVD, the magnitude of the vertical
deviation must be assessed. DVD is characterized by the variability
of its measurements, but this should not discourage the surgeon to try
and obtain the most accurate measurement possible since the surgical
plan will be different depending upon the magnitude of the deviation.

DVD is often asymmetric, and it can be very asymmetric. Sometimes
to a point that it appears to be truly unilateral.

In general, DVD is slightly incommitant, larger in abduction, but there
are 3 situations where this incommitancy is more noticeable:

1. Patients with coexistent Inferior oblique overaction will show a
larger deviation in adduction, V pattern and excyclotorsion when
looking at the fundus.

2. Patients with superior oblique overaction will show a larger
deviation in abduction, A pattern and incyclotorsion.

3. A larger deviation in abduction can also be seen in cases associated
with superior rectus overaction/contracture syndrome and these
cases will be different from the previous ones in that they have no
A pattern and they exhibit a positive Bielschowsky head tilt when
the head is tilted to the side of the larger hypertropia.

82 CME on COMPLEX STRABISMUS

Dissociated Vertical Deviation

For this reason, the size of the DVD should be measured also
in abduction and adduction and alphabetical patterns should be
considered as well as torsion when examining the fundus.

Confusion within DVD and isolated inferior oblique overaction is
quite common since both may cause elevation of the eye in the primary
and adducted position. Also, a combination of these two entities is not
infrequently seen. Table 1 points out important differences between
both.

TABLE 1.

Inferior Oblique DVD
Overaction
No pattern
Pattern V pattern Hypertropia in
primary, adduction and
Vertical deviation Hypertropia in abduction
primary and No hypotropia of the
adduction abducting eye
Usually present
Cover test in side Hypotropia of the Slow (2-200 degress/
sec)
gazes abducting eye No torsion

Latent nystagmus Usually not present

Speed of the Fast (200-400
deviation degrees/sec)

Fundus findings Excyclotorsion

Management

NON SURGICAL
Treatment of this disease, when indicated, is always surgical. But before
considering a surgical correction, trying to encourage some fusion or
binocular fixation in the patient with an accurate optical correction or
by treating a preexisting amblyopia can diminish decompensation of
the DVD.18,19 It is much better to observe a patient in whom the DVD
is controlled as a phoria and only decompensates when occluding her
eyes. (Figure 4)

CME on COMPLEX STRABISMUS 83

Dissociated Vertical Deviation

(Figure 4) Patient with right DVD that only decompensates without optical correction.

Surgical

There are three situations when surgical management of DVD should
be recommended to the patient:
1) Patients with a DVD that is large and decompensates very

frequently resulting in a cosmetic problem.
2) Patients at risk of developing or worsening an existing amblyopia

when the deviation is frequent enough to produce intense
suppression of the deviated eye.
3) Patients who adopt a significant anomalous head posture to control
the magnitude of the DVD.
Once surgery is indicated and before considering a surgical plan, it
is important to evaluate the different clinical characteristics of the
deviation to come up with the best surgical strategy.
The different surgical strategies should consider controlling the
incomitance as well as the DVD.
The existence of numerous different surgical options for treatment of
DVD reflects the fact that none of these are completely satisfactory.
The best expected result is diminishing and/or improving the control
of the deviation.

84 CME on COMPLEX STRABISMUS

Dissociated Vertical Deviation

Surgical procedures described to treat dissociated vertical deviation
include:
1) Superior rectus recessions
a. Large recessions for bilateral cases
b. Moderate recession when only one eye is going to be operated
on.
2) Small recession of superior rectus with posterior fixation
3) Recession of superior rectus with Y splitting
4) Inferior Oblique Anterior Transposition. There are some variants

described like:
a. Graded recessions
b. Augmented by resections
c. Nasal Transposition
5) Plication/Resection of the Inferior Rectus
6) Weakening of all 4 oblique muscles
7) Recession of both inferior recti.

Superior rectus recession is one of the most popular procedures to
treat DVD. Recessions in these cases must be larger than in other types
of vertical deviations.20,21 There are different surgical tables in the
literature. Table 2 shows the numbers used by the author of this chapter.

Table 2. Recommended numbers for superior rectus recession
in bilateral and unilateral cases.

DVD Bilateral Superior Unilateral Superior
rectus recession rectus recession
Up to 10 pd 7 mm 5 mm
10 to 20 pd
More than 20 pd 8 - 10 mm 6 - 7 mm
11 -14 mm 8 - 9 mm

There is a controversy regarding suturing the muscle directly to the
sclera or using hang back sutures. According to Julio Prieto Diaz, hang-
back suture is a better choice in exceptionally large recessions because
when the recession is performed, the eye is extremely depressed and
the superior oblique tendon slides posteriorly. When the eye returns
to primary position at the end of the procedure, the normal path of
the superior oblique will be disturbed by the fixed superior rectus if
sutures are placed in the sclera.22 (Figure. 5)

CME on COMPLEX STRABISMUS 85

Dissociated Vertical Deviation

Figure 5 : Taken from Julio Prieto Diaz, Carlos Souza Días. Estrabismo. Ediciones
Científicas Argentinas, 5ta Edicion, 2005.

There is evidence that exaggerated recessions (over 10 mm) of the
superior rectus using a hang back technique, can be less predictable
and fixed scleral sutures might provide a more reliable result.23
To assure that the superior rectus is weakened appropriately and to
avoid palpebral fissure changes, it is important to perform an extensive
dissection of the tissues surrounding the superior rectus which includes
the check ligaments, the intermuscular membrane and especially the
frenulum which is the tissue connecting the superior oblique to the
superior rectus muscle. (Figure. 6)

Figure 6 : The forceps grabs the tissue underneath the superior rectus that connects
with the anterior surface of the superior oblique. This connecting tissue is called the

frenulum.
86 CME on COMPLEX STRABISMUS

Dissociated Vertical Deviation

Inferior oblique anterior transposition is also a popular procedure to
treat DVD and it is the preferred approach when there is coexistence of
inferior oblique overaction. In 1978 Scott demonstrated the mechanical
advantage of using this procedure over a conventional recession with
help of a digital model.24 Elliott and Nankin published the first series
comparing inferior oblique anterior transposition to standard inferior
oblique muscle recession.25 The first published report on the benefit of
anterior transposition of the inferior oblique in patients with DVD was
done by Mims and Wood.26 After this report, several authors confirmed
the effectiveness of anterior transposition of the inferior oblique for
the treatment of DVD.27,28,29,30,31

Anterior transposition of the inferior oblique reduces the hypertropia
of mild and moderate DVD cases to an acceptable amount and at
the same time eliminates the inferior oblique overaction and the V
pattern with a low incidence of recurrence. This approach has also
been reported to be successful even in patients with no inferior oblique
dysfunction.

In this procedure the tendon of the inferior oblique is disinserted and
transposed next to the lateral border of the inferior rectus. (Figure. 7)

Figure. 7 Anterior transposition of the inferior oblique NFVB (neurofibrovascular
bundle)

CME on COMPLEX STRABISMUS 87

Dissociated Vertical Deviation

Stager has shown that the neurofibrovascular bundle (NFVB) that
inserts into the midportion of the inferior oblique muscle and runs
parallel and adjacent to the lateral border of the inferior rectus towards
the orbital apex, prevents the eye from drifting upwards in DVD.32

Some authors recommend graded inferior oblique resection of
the transposed tendon to increase effectiveness in larger DVD of
asymmetric cases.33 Other authors have not found benefit in augmenting
the standard surgery.34

Another grading system for this surgery is placing the posterior fibers
of the inferior oblique muscle anterior or posterior to the lateral border
of the inferior rectus muscle.27 Again, other authors do not agree
that anterior placement of the inferior oblique muscle does increase
effectiveness of this procedure.35

Instead of transposing the inferior oblique tendon to the temporal
border of the inferior rectus, anterior transposition of this muscle to
the nasal border of the inferior rectus has also been proposed for the
treatment of this disease. According to the author this technique not
only reduces overelevation in adduction but also may decrease the risk
of an antielevation syndrome.36

Posterior fixation (Faden) has been described as a primary treatment
for DVD. It is usually combined with small recessions (up to 5mm) of
the superior rectus.37 This is a relatively difficult procedure, especially
if the surgeon does not perform this frequently. The posterior non-
absorbable suture must be placed between 12 to 15 mm from the
superior rectus insertion, so a good assistant is needed to perform this
procedure. Some authors have found this technique to have a better
long-term effect than large recessions of the superior rectus muscle.38

Y-split with recession of the superior rectus is also indicated in large
dissociated vertical deviation without inferior oblique overaction.
This procedure allows larger angle corrections with smaller amounts
of recessions.

Y-split recession of a muscle decreases the lever arm, and hence the
torque generated by it, without changing the location of the muscle
pulley. This torque reduction occurs in all eye positions, with a more

88 CME on COMPLEX STRABISMUS

Dissociated Vertical Deviation

pronounced effect in the field of action of the muscle, unlike Faden,
where the weakening effect is minimal in other gazes.39

Ease of the surgical procedure, and preservation of normal ductions
are benefits of the Y-split procedure, compared to Faden.

Inferior rectus resection or plication has been proposed as a primary
procedure for DVD,40 but is usually considered as a secondary
procedure for recurrent or residual DVD.41 It should be moderate (up
to 5 mm) to avoid restriction of elevation and narrowing of palpebral
fissure.

Weakening of the 4 oblique muscles. Recess and anteriorly transpose
all oblique muscles is a technique suggested by David Guyton based
on the belief that the oblique muscles are involved in the appearance
of DVD.8 Some papers have been published demonstrating that this
technique can be useful in cases of symmetric DVD with significant
A patterns (more than 15 diopters) due to the coexistence of superior
oblique overaction.42,43,44

Bilateral inferior rectus recession is a technique proposed by David
Romero Apis.45 This surgery is based on the fact, that by recessing both
inferior recti, these muscles will need more innervation to maintain the
eye in primary position. Through Sherrington’s law this will produce
an inhibitory effect on the superior recti which will help in controlling
the decompensated upward movement. This technique seems to be
useful only in cases where the DVD disappears when fixing with a
chin-up posture. (Castellanos Maneuver)

Algorithm for the Surgical Treatment of DVD

In patients with symmetric or asymmetric (more than 7 PD)
bilateral DVD and without inferior oblique overaction, symmetric
or asymmetric recession of both superior recti is a reasonable procedure
to bear in mind.(Figure. 8) Unilateral recession of the superior rectus
can be considered in unilateral DVD when fixation with the deviated
eye is very unlikely. Smaller recessions of the superior recti can be
performed when combined with a posterior fixation (faden) or a Y
split.

CME on COMPLEX STRABISMUS 89

Dissociated Vertical Deviation

Figure 8: Patient with DVD (A) before and (B) after bilateral superior rectus
recession 9mm OD 10 mm OS

Patients with DVD that also exhibit inferior oblique overaction will
benefit from an anteriorization of this muscle. This will correct DVD’s
up to 18-20 PD. (Figure 9 and 10) If the angle of the DVD is larger, the
inferior oblique anteriorization can be combined with superior rectus
recession.46

Figure 9: Same patient from Figure. 3 that develops bilateral inferior oblique
overaction and DVD after the bimedial rectus recession

Figure 10: Same patient 20 years after anteriorization of both inferior obliques.
90 CME on COMPLEX STRABISMUS

Dissociated Vertical Deviation

Patients with DVD and superior oblique overaction and an A pattern,
the best surgical strategy will depend on the magnitude of the A
pattern. If the A pattern is up to 10 pd, only the recession of both
superior recti will correct this pattern. If the A pattern is between 10
and 20 pd, a posterior tenectomy of both superior obliques should be
added to improve DVD and A pattern. Finally, if the A pattern is larger
than 20 pd a complete tenectomy of the superior oblique should be
considered.47,48,49 (Figure11) In cases of symmetric DVD and A pattern
another procedure that might yield to good results is weakening the
four oblique muscles.42,43,44

CME on COMPLEX STRABISMUS 91

Dissociated Vertical Deviation

Figure 11: Patient operated for congenital ET at the age of 1 year developed
DVD several years after and superior oblique overaction with A pattern. (A) before
surgery (B) After bilateral superior rectus recession and posterior tenectomy of both

superior obliques, notice improvement in DVD and collapse of the A pattern.

In cases with a residual and significant DVD that previously had
anteriorization of the inferior obliques, recession of both superior recti
can be added and vice versa. Weakening of both elevators appears to
be a safe approach in the management of large or recurrent DVD.46,50
Another procedure that can be considered in this clinical scenario,
especially if the surgeon is concerned about causing “double-elevator
weakness” is the inferior rectus resection or plication.(Figure 12 & 13)

Figure 12: Patient operated for congenital cataract and with a bilateral superior
rectus recession for bilateral DVD now showing recurrent DVD on his left eye.

92 CME on COMPLEX STRABISMUS

Dissociated Vertical Deviation

Figure 13: After plication of the left inferior rectus 6 mm.

Complications

The most common complication after DVD surgery is recurrence or
persistence of the deviation.

Hypotropia can follow either unilateral superior rectus recession or
asymmetric bilateral superior rectus recession and it is a sign of an
overcorrection.51 Inferior rectus resection and anterior transposition
of the inferior oblique can also lead to this result, especially if done
unilaterally.52

Development of an anti-elevation syndrome as described by Kushner
in 1997 is a complication that can occur after anterior transposition of
the inferior oblique muscle.53 This occurs because the vector force of

CME on COMPLEX STRABISMUS 93

Dissociated Vertical Deviation

the anterior portion of the anteriorized inferior oblique muscle runs
parallel to the inferior rectus producing an anti-elevation force that is
more pronounced in abduction. This complication is more frequently
seen in cases where the inferior oblique is placed anterior to the
temporal border of the inferior rectus and especially if the posterior
fibers are spread out laterally and not bunched together with the
anterior fibers.

Widening of the palpebral fissure is a complication that can occur after
large recessions of the superior rectus, especially if the muscle is not
carefully dissected from all its surrounding tissues. Narrowing of the
lid fissure can occur after resection of the inferior rectus.54,55 This last
complication can be avoided by dissecting Lockwoods ligament from
the inferior rectus.

Eyelid “fullness” can be observed after anterior transposition of the
inferior oblique.56 This usually disappears with time.

Conclusions

Dissociated vertical deviation is a condition that cannot be cured.
Surgical treatment can reduce the amplitude of the DVD and the
frequency of the manifest hyperdeviation, but does not alters the basic
defect nor eliminate the presence of the deviation. The best expected
result is a better control of the deviation. DVD can manifest in
different clinical scenarios and the surgical strategy must be adjusted
accordingly. Therefore, the patient must be carefully examined in
order to reveal all clinical findings that might be present and determine
the best surgical plan for each case.

References

1. Helveston EM: Dissociated Vertical Deviation-a clinical and laboratory study.
Trans Am Ophthalmol Soc 1980;78:734.

2. Christoff A, Raab EL, Guyton DL, Brodsky MC, Fray KJ, Merill K, Hennessey
CC, Bothun ED, Morrison DG. DVD-a conceptual, clinical and surgical
overview. J AAPOS 2014;18:378-384.

3. Wilson ME, McClatchey SK. Dissociated horizontal deviation. J Pediatr
Ophthalmol Strabismus 1991;28:90-5.

94 CME on COMPLEX STRABISMUS