Duane Syndrome Eye
SYNDROMES ASSOCIATED WITH STRABISMUS/ SQUINT:
(duane syndrome eye) Squint is the improper alignment of the eyes. The condition can be congenital or acquired. Congenital squint can be associated with certain syndromes involving other parts of the body.
In congenital squint focus should be made on early detection of the syndromes associated with the squint.
Congenital ocular fibrosis of extraocular muscle (CFEOM):
Congenital restrictive ophthalmoplegia affects the oculomotor and trochlear nerve and can cause bilateral ptosis and strabismus. Congenital ocular fibrosis of extraocular muscle (CFEOM) includes Duane’s and Brown’s syndrome.
What is Duane Syndrome Eye:
Duane’s syndrome accounts for 1- 4 % of strabismus patients. In Duane syndrome, there is limited abduction with the widening of the palpebral fissure and are traction of the globe on adduction with a narrowing of the palpebral fissure.
Up-shoots and down-shoots of the eyes are also common. It is a congenital fibrosis syndrome with absent or defective cranial nerves. Most of the patients have binocular single vision. Duane’s syndrome has three types.
In Type I Duane’s syndrome there is manifest esotropia in primary position with limited abduction and little or no adduction deficit. Type II is an exotropia in the primary position with limited adduction.
Type III has limited abduction and adduction, hence may have esotropia or an exotropia in primary position.
In Moebius Syndrome 6th and 7th cranial nerves palsy is present that results in lateral gaze palsy and facial paralysis. The presenting sign is a large angle (more than 50 prism dioptres ) congenital esotropia.
What is Brown Syndrome:
Brown’s syndrome presents as an ipsilateral limitation of elevation, most marked in adduction. It may also show a down-drift of the eye on adduction. Most patients have straight eye alignment in the primary position of gaze with a binocular single vision.
In some cases, the adoption of an abnormal head posture with chin elevation is developed. Brown syndrome is suggested to be autosomal recessive or autosomal dominant.
OTHER CRANIOFACIAL SYNDROMES ASSOCIATED WITH STRABISMUS
Wide epicanthus can appear like strabismus (pseudo-strabismus). Premature closure of cranial sutures can result in asymmetry of the skull. It may also affect the shape and size of the globe as well as change the elasticity of extraocular muscles.
Secondary Fibrosis of extra-ocular muscle is also one of the causes of strabismus. These syndromes commonly show an autosomal dominant trait (Apert’s, Crouzon’s, Treacher-Collins, Franceschetti, and Waardenburg’s syndromes). Many craniofacial patients, who underwent strabismus surgery have been reported to have a total absence of extraocular muscle.
The severity of skeletal deformity is associated with the degree of misalignment. Some craniofacial disorders involve defects of different chromosomes with similar strabismus phenotypes. For example, Apert’s Syndrome is associated with esotropia, exotropia, and hypertropia.
Kearns-Sayre syndrome is associated with mitochondrial gene deletion as well as structural defects in extraocular muscle mitochondria.
CHROMOSOMAL SYNDROMES ASSOCIATED WITH STRABISMUS
What is Down Syndrome:
Down’s syndrome is associated with an abnormality of the chromosomes due to trisomy of chromosome 21. There is a high risk of developing ocular defects in Down’s syndrome including strabismus, refractive error, reduced visual acuity, poor contrast sensitivity, insufficient accommodation, short sloping palpebral apertures, nystagmus, and peripheral atrophy of iris stroma.
Albinism is an inherited disorder that is characterized by the reduction or absence of melanin in the hair, skin, or eyes. It is due to a deficiency of the melanin-producing enzyme tyrosinase. Melanin is essential for the retinal pigmented epithelium and plays a role in normal vision development.
Albinism is divided into two types. In ocular albinism, only eyes are affected. In oculocutaneous albinism, there is hypopigmented skin and eyes. Foveal hypoplasia, strabismus, high refractive error, and/or nystagmus are the causes of reduced vision.
In albinism significantly high refractive error (>10.0 dioptres), with mixed astigmatism is commonly reported. Deficient pigmentation may cause abnormal decussation of optic nerve fibers that leads to a lack of binocular vision and possibly strabismus. Increased incidence of strabismus have been reported specifically accommodative esotropia