ETIOLOGY,CLINICAL FEATURES & MANAGEMENT OF ACCOMODATIVE ESOTROPIA

ETIOLOGY,CLINICAL FEATURES & MANAGEMENT OF ACCOMMODATIVE ESOTROPIA

DR. SAMARTH MISHRA

.

esotropia

. TYPES OF ESODEVIATIONS:INCOMITANT:

Paralytic -neurogenic( e.g abducens palsy,divergence palsy) -myogenic (e.g myasthenia)

Restrictive -musculofascial( e.g duanes) -other restrictive conditions( e.g tumor,postoperative,dysthyroid,strabismus fixus)

c) Spastic

.CONCOMITANT:

Accommodative -refractive( hypermetropic) -non refractive,hyperaccommodative,hypoaccommodative

B) Partially accommodative

Non-accommodative

-essential infantile. -essential acquired/late onset -- basic --convergence excess --divergence insufficiency -acute concomitant -microtropia -cyclic esotropia -sensory esotropia -nystagmus blockage syndrome -esophoria.

CLASSIFICATION OF ESOTROPIA:

.CLASSIFICATION:

TYPE CRITERIONNON-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 )

.-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.

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.Infantileessential

.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 6.5mm.

-goal is to align eyes within 10D.

EARLY ONSET ESOTROPIA AFTER SURGICAL CORRECTION

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.

dissociated vertical deviation(DVD)

.DIFFERENTIAL DIAGNOSIS:

Congenital b/l 6th n. palsy.

Secondary( sensory ) esotropia.

Duane syndrome type 1 & 3.

Mobius syndrome.

Strabismus fixus

Nystagmus blockage syndrome.

ACCOMMODATIVE ESOTROPIA:

.

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

.Symptoms:

-diplopia-eyestrain-headache-blurred vision-decreased depth percption-crossing/ inward deviation of the eyes.

.

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.

.

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.

.

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.

.

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.

. Divided into:

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.

.

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

.

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.

MEDICAL TREATMENT:

For fully accommodative (refractive)esotropia:-refractive error should be corrected.-in children 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.

.

.

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.

.ACUTE( LATE ONSET) ESOTROPIA: -presents around 5-6 yrs for no apparent reason.Signs:Sudden onset of diplopia.Normal ocular motilityNo 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.

. 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.

.MICROTROPIA (MONOFIXATION SYNDROME):

-two types: 1)park monofixation syndrome 2)langs 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,

.

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.

Crossed eyed appearance gets corrected with elimination of prominent epicanthic fold

: note the corneal light reflex.

. thank you