Internal Medicine

0521779407-19 CUNY1086/Karliner 0 521 77940 7 June 6, 2007 17:50

1378 Strabismus

■Family history may be positive. Congenital esotropia more com-

mon in neurologically impaired children. Maternal smoking is a risk

factor.

Signs & Symptoms

■Esotropia is crossed eyes. Look for light reflex displaced temporally.

■Accommodative esotropes may show variable strabismus, worse

with near visual tasks.

■Amblyopia (loss of vision due to non-usage of eye) most likely in

accommodative esotropia.

■Depth perception affected with misaligned eyes-may not recover

with correction of strabismus.

■Exotropes usually squint one eye in bright light. Eyes diverge. Look

for light reflex displaced nasally.

■Vertical strabismus patients take an anomalous head position to

keep eyes aligned and avoid double vision.

■Sixth nerve palsy causes esotropia. Involved eye won’t abduct (turn

out). Third nerve palsy usually shows involved eye “down and out.”

Fourth nerve palsy causes head tilt.

tests

■Physical Exam

➣Usually the only “test.” Cover test – cover fixing eye and look to see

whether uncovered eye shifts to look at the visual target. Forced

duction (traction on eye to palpate resistance to movement of

eye) for restrictive disease diagnosis (e.g., tight muscle in Graves

disease). Myasthenia suspect – Tensilon test.

■Imaging

➣Brain for suspected space-occupying lesion: cases late in onset

(esotropia after age 5); other neuro signs, esp. cranial nerve loss;

papilledema; constant exotropia first year of life

differential diagnosis

■Esotropia

➣1. Pseudoesotropia occurs when epicanthal folds cause illusion

of esotropia. Look for light reflex off center of corneas and

normal cover test.

2. Sixth nerve palsy causes poor abduction movement of affec-
   ted eye.


3. Duane syndrome is anomalous innervation of extraocular
   muscles. Left eye usually affected and won’t abduct or adduct.