I. Introduction: After discussing the methods in which to measure and detect the suspect muscle involved in an non-comitant strabismus, It may be useful to review some of the possible congenital oculomotor syndromes that you may observe during your careers. A non-comitant strabismus is defined as a strabismus in which the angle of deviation varies in different gaze. Traditional thought would have us believe that these cases are acute, adult onset strabismics who suffer from diplopia and visual disorientation. It should be stressed, however, that non-comitancy may be congenital .
A. Congenital non-comitancies:
1. A congenital or early acquired non-comitancy will be accompanied by the traditional sensory adaptations that we have come to know and love.a. Suppression may be present.i. could be only located in gaze positions that the strabismus is manifestii. i.e. 40" stereo may be present in primary gaze and suppression present in superior gaze.
b. ARC may be present.
i. could be only located in gaze positions that the strabismus is manifestii. i.e. 40" stereo may be present in primary gaze and hARC present in superior gaze.
2. A long standing congenital strabismic will usually acquire some torticollis (abnormal head posture) to compensate for the "damaged" EOM. You can obtain valuable information by carefully observing your patient from the moment they are greeted. Compensatory head turns or tilts may be noticed. You can begin your diagnostic quest, then, as you first see the patient.
a. Abnormal head turns assoc. with horizontal non-comitancy.b. Abnormal chin position assoc. with vertical non-comitancy.
c. Abnormal head tilt assoc. with cyclo non-comitancy (i.e.. obliques).
d. Extreme torticollis is NOT usually present in congenital strabismics; they can use their sensory adaptations instead.
B. An optometrist's role here is to make a proper diagnosis of the condition.
1. Often a thorough case history will reveal most of the information you need to know.a. How long standing is the conditionb. Are there any medical records of this condition (i.e.. has it already been diagnosed and treated)
c. Are there any sensory adaptations to the strabismus (indicating a long standing and stable condition).
2. The examination, no matter what the case history reveals is to find the following:
a. Which EOM(s) is/are involvedb. What is causing the non-comitancy
i. Is it a paralysis or paresis of the EOM s)ii. Is it a mechanical obstruction of the EOM(s)
iii. Is it an associated condition to a congenital horizontal strabismus
3. After proper care has been completed, the optometrist's role is to provide the proper therapy regimen to increase the patient's functional ability.
II. Common Syndromes of Non-Comitancy (A-V)
A. A-V Pattern: A horizontal strabismus that is non-comitant in vertical directions of gaze.
1. When there is more divergent position in elevation than depression, called a V-Syndrome.a. the letters tell you about the magnitude of the angle as the patient looks up or down.b. V-syndrome esotropes are more eso on inferior gaze.
c. V-syndrome exotropes are more exo on superior gaze.
2. When there is more convergent position in elevation than depression, called an A-Syndrome.
a. the letters tell you about the magnitude of the angle as the patient looks up or down.b. A-syndrome esotropes are more eso on superior gaze.
c. A-syndrome exotropes are more exo on inferior gaze.
3. The etiology of these patterns is not too clear.
a. Theories suggesting any of the vertical recti or obliques may be responsible.
III. Congenital Strabismus Syndromes
A. Duane Retraction Syndrome:
1. It may me monocular or binocular.2. It has three categories. All have globe retraction on adduction.
a. TYPE I: imagei. abnormal abductionii. narrowing of the palpebral fissure and retraction of the globe on adduction
iii. adduction of that eye, however, is close to normal.
b. TYPE II: image
i. abnormal adductionii. retraction of the globe on adduction
iii. exotropia of the affected eye
iv. abduction of that eye is close to normal.
c. TYPE III: image
i. severe restrictions of both adduction and abductionii. narrowing of the palpebral fissure and retraction of the globe on attempts to adduct only
B. Brown's Syndrome: usually congenital, but has acquired forms. image
1. In the congenital form, it most commonly results from a "tight "superior oblique tendon.2. Its features include:
a. Limitations of elevation on adductionb. Nearly normal elevation on abduction
c. Widening of the palpebral fissure on attempts to elevate while adducting.
C. Dissociated Vertical Deviation (double hyper deviation)
1. Both eyes will elevate when behind the occluder.a. It may be a double hyperphoriab. It may be a double hypertropia
2. This condition will interfere with the management of the strabismus.
3. Congenital ETs with a DVD often have a latent nystagmus (i.e. a nystagmus only present when an eye is occluded.
a. It may be unilateral or bilateral.b. The slow phase of the nystagmus is usually towards the occluder.
D. Double Elevator Palsy: elevation of the affected eye is compromised whether abducted or adducted
1. Apparent weakness of the SR and IO of the affected eye image2. Pupils, MR are not involved
3. In some cases forced duction tests are negative and Bell's phenomenon is intact indicating a supranuclear source for the dysfunction
4. It is usually monocular
E. Marcus Gunn Jaw-Winking Synkinesis: an abnormal coordinated movement between the muscles of mastication (trigeminal motor nerve) and the levator palpebrae (oculomotor nerve). Ptosis is present in these cases. image
1. May be as high as 5% of all individuals with congenital ptosis2. The external pterygoid and the levator are the muscles that are usually the culprits.
3. The result is palpebral fissure opening (lessening the ptosis) when the jaw is thrust to the opposite side (this would be with the ipsilateral external pterygoid.
