Duane retraction syndrome is characterised by retraction of globe (eyeball) on attempted adduction (inward movement) caused due to co-contraction of both medial and lateral rectus muscle of the involved eye.
Duane retraction syndrome is a non-progressive congenital disorder of eye movement, which may occur either in isolation or in the form of syndrome associated with other congenital defects, most common is perceptive deafness with associated speech disorder. It may be associated with strabismus in primary gaze.
Horizontal eye movement is governed by lateral rectus muscle, which pulls the eye outward and by medial rectus muscle, which pulls the eye inward. When lateral rectus muscle of an eye contracts and pull the eyeball outward, the medial rectus of the same eye relaxes. The contra-lateral medial rectus muscle contracts and the lateral rectus muscle relaxes to a similar extent for smooth movement of eyeballs.
There are three main types (Huber classification):
- Type 1: This is characterised by limitation or absence of abduction (outward movement) with normal or mildly restricted adduction. This is the most common type.
- Type 2: This is characterised by limited adduction with normal or mildly restricted abduction. This is the least common type.
- Type 3: This type shows limitation of both abduction and adduction.
Kanski,Jack J. Clinical Ophthalmology, A Systematic Approach .Third Edition.UK. Butterworth Heinemann, 1994.
Duane retraction syndrome may be associated with some or all of the following features:
- Retraction of globe on adduction.
- Complete or partial limitation of abduction.
- Narrowing of palpebral fissure on adduction.
- Widening of palpebral fissure on attempted abduction.
- Partial limitation of adduction.
- Convergence insufficiency.
- Oblique movement of globe on attempted adduction.
- Upshoot or downshoot of globe with adduction (Leash or Bridle Phenomenon).
Duane retraction syndrome is thought to be due to aberrant innervations of medial and lateral rectus muscles. In addition, structural anomalies of the muscle or primary anomaly of the brainstem may be contributing as aetiological factors. Most likely, both genetic and environmental factors play a role in the development of this syndrome.
Duane retraction syndrome may occur as an isolated phenomenon or present as a syndrome.
This comprises 90% of cases which are sporadic and unilateral. Remaining 10% may be inherited, bilateral and may have vertical movement abnormalities. These may be autosomal dominant or autosomal recessive.
Association with syndromes:
This may be associated with different syndromes like:
- Goldenhar syndrome: It is characterised by malformation of jaw, cheek and ear usually on one side of the face.
- Morning glory syndrome: It is characterised by abnormalities of the optic disc.
- Moebius syndrome: This may show congenital paresis of facial (VIIth) and abducent (VIth) cranial nerves.
Patient may present with:
- Manifest squint.
- Reduced abduction in affected eye.
- Loss of binocularity.
- Head turn to maintain fusion.
- Certain associated eye conditions like heterochromia, pupillary abnormalities, cataract or microphthalmos (small eyeball).
Patient may carry an old picture of strabismus.
Clinical features of different types:
- Type 1: The abduction or ability to move the eye outward is limited, but adduction or ability to move the eye inward is normal or nearly so. There is retraction of the eyeball (enophthalmos) with narrowing of the palpebral fissure on adduction. The eyeball assume its normal position and the palpebral fissure widens again on attempted abduction.
- Type 2: In this type, affected eye shows limitation of adduction but the abduction is normal or nearly so. On attempted adduction, there is retraction of the globe and narrowing of the palpebral fissure.
- Type 3: There is limitation of both adduction and abduction. The eyeball retracts and the palpebral fissure narrows on attempted adduction.
Non surgical management:
Patient with orthophoria (straight eyes in primary position) should be managed conservatively.
- Associated refractive error may be corrected with suitable spectacles or contact lenses. Compensatory head turn patients may be treated by incorporating prisms in glasses.
- Similarly, any associated amblyopia is treated.
Surgery should be avoided if patient shows some form of binocular vision.
Surgery is considered when a patient show features like:
- Significant deviation of eye in primary position.
- Significant head turn
- Severe narrowing of palpebral fissure on adduction.
- For cosmetically unacceptable up-shoots or down-shoots
Depending on the type, surgical procedure may be:
- Recession of the medial rectus muscle and/or lateral rectus muscle with possible Y-splitting.
- Posterior fixation suture.