7. .
CLASSIFICATION:
TYPE CRITERION
NON-ACCOMMODATIVE esotropia at
distance=near fixation.
no change with refractive correction
ACCOMMODATIVE:
- refractive( normal AC/A ratio) esotropia at distance >/= near fixation.
( fully corrected by hyperopic
correction for distance )
8. .
-Non-refractive: esotropia at near
(high AC/A ratio) fixation>distance or manifesting
only at near.
(fully corrected by an additional
hyperopic correction for near work)
-mixed
PARTIALLY ACCOMMODATIVE: esotropia partly
corrected by the use of
refractive correction.
9. CONVERGENT SQUINT/ ESOTROPIA/
ESODEVIATION:
Denotes inward deviation of eye.
Esotropia(manifest convergent squint) may be concomitant or incomitant.
In a concomitant esotropia the variability of the angle of deviation is < 5
prism dioptres.
It can be a) unilateral: the same eye always deviates inwards & the second
normal eye takes fixation.
b) alternating: either of the eyes deviates inwards & the other eye
takes the fixation,alternately.
ETIOLOGY:
more common in childhood & hypermetropes.
Congenital esotropia: may be associated with neurological disorders.
May be hereditary.
Infantile
essential
10. .
EARLY ONSET ESOTROPIA:
-upto 4 months infrequent episodes of convergence is normal
-True “congenital” esotropia observed at birth is very rare,their eye alignments
remain in a state of flux till 4 months of age.
- >4 months, ocular misalignment is abnormal.
-therefore, it is imperative to observe these children closely in the first four
months before establishing a diagnoss of esotropia.
-early onset esotropia is an idiopathic condition developing <6 months of life
in an otherwise normal infant with no significant refractive error & no
limitation of ocular movt.
-The multicentric congenital esotropia study has concluded that small angle
esotropia <30pd may be observed as some of these may get spontaneously
corrected.
11. .DIAGNOSIS:
- Angle > 30 prism dioptres and stable.
- Fixation is alternating in the primary position.
- May give a false impression of bilateral abduction deficits, as in bilateral 6th n.
palsy.
- Abduction can be demonstrated by uniocular patching (for a few hours) or
doll’s head phenomenon.
- Nystagmus is usually horizontal.
- Confirmed by 4-6 months
- Cross-fixing in side gaze:- i.e the child uses the left eye in right gaze and vice
versa.
14. .
-latent nystagmus is only seen when one eye is covered & the fast phase
beats towards the fixing eye.
- i.e the direction of fast phase reverses according to which eye is covered.
- Refractive error normal for age.( +1 to +2 D)
- Dissociated vertical deviation (DVD)develops by 3 yrs.
- Asymmetric optokinetic nystagmus..
15. . VARIANTS:
CIANCIA SYNDROME:
(early onset esotropia + B/L limitation of abduction with manifest-latent
jerk nystagmus [fast phase towards fixing eye] )
LANG’S SYNDROME:
(early onset esotropia + DVD +nystagmus+excyclodeviation)
16. .Treatment :
-ocular alignment is most imp.
-surgically by 1 year.[ latest by 2 years], only after correction of amblyopia or
refractive error.
-recession of both medial recti/ unilateral medial recti with resection of
lateral recti.
-Very large angles require recessions of >6.5mm.
-goal is to align eyes within 10D.
18. SUBSEQUENT TREATMENT:
-undercorrection: may require furthur recession of medial rectus ,resection of one or both
lateral recti or surgery to other eye.
-inferior oblique overaction: may develop subsequently. M/C around 2yrs.
Parents shpuld therefore be warned that furthur surgery maybe necessary despite initial
good result.
Unilateral, and frequently becomes bilateral within 6months. It is over-elevation of eye in
supra-adduction.
-Amblyopia: devp in 50percent cases.
-DVD: appear several yrs after.
It is the elevation of non-fixing eye when covered or with visual inattention.
23. ACCOMMODATIVE ESOTROPIA:
It is a condition where in excessive effort of accommodation results in an
inward deviation of eyes.
Occurs due to overaction of convergence associated with convergence
reflex.
Most often caused by uncorrected hypermetropia.
It is of three types: a) refractive
b)non refractive
c)mixed
25. .
Refractive(hyperopic) accommodative esotropia:
usually develops at the age of 2 to 3 years & is associated with high
hypermetropia(+4 to +7D).
mostly it is for near and distance.
fully correctable by the use of spectacles.
there is a tendency for the deviation in all cases of esotropia to diminish
with the diminution of accommodation with age.
normal AC/A ratio.
26. .
Since they have normal AC/A ratio ,the esodeviation is the same for
distanceand near fixation i.e they lack convergence excess.
However, in some children,who donot make an effort to clear retinal blur by
accommodating or if hypermetropia is too high to overcome with
accommodation, this uncorrected hyperopia leads to bilateral ametropic
amblyopia but no esotropia.
27. .
A) FULLY ACCOMMODATIVE:
- eliminated by optical correction of hypermetropia.
- BSV is present at all distances with glasses.
- Deviation still present when glasses are not worn.
- Amblyopia if present must be treated with appropriate patching regime.
B) CONSTANT ACCOMMODATIVE ESOTROPIA:
-reduces, but not fully on refractive correction.
-amblyopia,B/L congenital superior oblique weakness are frequent.
28. .
Non-refractive accommodative esotropia:
-such cases donot accommodate for distance but obly for near fixation
-chr. by abnormally high AC/A ratio.
-A unit change increase in accommodation is accompanied by a
disproportionately large increase in convergence.
-occurs independently of refractive error,although hypermetropia
coexists.
-esotropia is greater for near than that for distance
( minimal or no deviation for distance )
-it is fully corrected by adding +3DS for near vision.
29. .
Divided into:
A)Convergence excess:
-high AC/A ratio d/t increased accommodative
convergence(accommodation is normal; convergence in increased)
-normal near point of accommodation.
-straight eyes with BSV for distance.
-esotropia for near, usually with
suppression.
-straight eyes through bifocals.
30. .
B) hypoaccommodative convergence excess:
-high AC/A ratio d/t decreased accommodation( accommodation is weak ,
necessitating increased effort, which produces over convergence )
-remote near point of accommodation.
-straight eyes with BSV for distance.
-esotropia for near, usually with suppression
31. .
Mixed accommodative esotropia:
-caused by combination of hypermetropia and high AC/A ratio.
-esotropia for distance is corrected by correction of hypermetropia, and the
residual esotropia for near is corrected by an addition of +3DS lens.
32. MEDICAL TREATMENT:
For fully accommodative (refractive)esotropia:
-refractive error should be corrected.
-in children <6 yrs, full cyclopegic refraction revealed on retinoscopy should
be prescribed. [with a deduction for working distance]
-< 8yrs refraction should be performed without cycloplegia & the maximal
amount of ‘plus’ that can be tolerated ( manifest hypermetropia)
prescribed.
For convergence excess (non refractive)esotropia:
-bifocals prescribed. :relieves accommoation and thereby accommodative
convergence.
-most satisfactory form of bifocals is the executive type in which the intersection
crosses the lower border of pupil.
-strength of lower segment should be gradually reduced & eliminated by the early
teenage years.
-in some cases bilateral faden operation on medial rectus alone is sufficient.
TREATMENT:
35. .SURGERY :
-aim of surgery: to restore/enhance BSV/to improve the appearance of squint.
-surgery is controversial & is not recommended in fully accommodative
refractive esotropia.
-only if spectacles donot correct deviation and after every attempt has been
made to treat amblyopia.
-B/L medial rectus recessions ( done for pts in whom deviation for near>
distance)
-unilateral medial rectus recession combined with lateral rectus resection can
be done.
-in patients with residual amblyopia surgery is usually performed on amblyopic
eye.
38. Some other esotropia:
NEAR ESOTROPIA:
signs:
-no significant refractive error.
-orthophoria or small esophoria with BSV for distance.
-normal near point of accommodation.
T/T: B/L medial rectus recession.
• DISTANCE ESOTROPIA: affects healthy young adults who are often myopic.
signs:
-intermittent or constant esotropia for distance.
-minimal or no deviation for near.
-normal B/L abduction
-fusional divergence amplitudes may be reduced.
T/T: with prisms,until spontaneous resolution. Surgery in persistant cases only.
39. .
ACUTE( LATE ONSET) ESOTROPIA:
-presents around 5-6 yrs for no apparent reason.
Signs:
- Sudden onset of diplopia.
- Normal ocular motility
- No significant refractive error.
- Underlying 6th n. palsy must be excluded.
-T/T: prisms/surgery/ botulinum toxin(lasts for short duration).
• SECONDARY ( SENSORY) ESOTROPIA:
- Caused by U/L reduction in V/A which interferes/ abolishes fusion.
- E.g in cataract, optic atrophy,macular scarring, retinoblastoma.
Fundus examination under mydriasis is therefore essential in all
children with strabismus.
40. .
CONSECUTIVE ESOTROPIA:
-follows surgical over- corection of an exodeviation.
-if it occurs following surgery for an intermittent exotropia in a child, it should
not be allowed to persist for more than 6 weeks without furthur
intervention.
CYCLIC ESOTROPIA:
-very rare condition characterised by alternating manifest esotropia with
suppression & BSV, each lasting 24hrs.
-may persist for months/years.
-pt may eventually develop constant esotropia requiring surgery.
41. .
MICROTROPIA (MONOFIXATION SYNDROME):
-two types: 1)park’ monofixation syndrome
2)lang’s microtropia
-may be primary or follow surgery for a large deviation.
-may occur in apparent isolation but often associated with other conditions.
e.g anisometropic amblyopia.
-it is more a description of binocular status than a specific diagnosis.
Chr:
-very small angle of manifest deviation.
-central suppression scotoma.
-ARC with reduced stereopsis & variable peripheral fusional amplitudes.
-anisometropia often present.
-defective stereo-acuity.
T/T:
Correction of refractive error & occlusion for amblyopia,
42. .
PSEUDO-ESOTROPIA:
-pseudo-esotropia is a condition in which the alignment of the eyes is
straight(= orthotropic),however, they appear to be crossed.
-due to prominent epicanthus or telecanthus.
-Needs reassurance.
43. Crossed eyed appearance gets corrected with elimination of prominent epicanthic fold
: note the corneal light reflex.