Duane retraction syndrome associated with oculocutaneous albinism
An ocular miswiring
Duane retraction syndrome (DRS) is characterized by globe retraction and palpebral fissure narrowing on adduction, with restriction of abduction or adduction or both.1 Oculocutaneous albinism (OCA) is a heritable, metabolic defect transmitted as an autosomal recessive trait and characterized by hypopigmentation of the skin, hair and eyes. The ocular signs and symptoms of OCA include photophobia, decreased visual acuity due to foveal hypoplasia; nystagmus and strabismus secondary to defective routing of optic axons in the chiasma.23 DRS and OCA display two distinct neural misdirection syndromes which may have occurred due to failure of neural connections in early stages of development. We report such a case.
A six-year-old female presented to us with history of involuntary eye movements since birth and squinting since two months of age. She was fair skinned with light blond hair with heterochromic iris noted from early infancy [Fig. 1]. On examination, her vision in right eye (RE) improved to 20/120 with a correction of +2.0 Diopter (D) sphere/ +2.0D cylinder 90°; left eye improved to 20/80 with +2.0 D cylinder 90°. Slit lamp examination showed iris transillumination. Indirect ophthalmoscopy revealed a small disc with absent foveal reflex with prominent choroidal vasculature [Fig. 2]. She had a 10° face turn to the left with manifest latent nystagmus. The pupil reacted normally to light. The orthoptic examination revealed a left esotropia of 45 Prism diopter (PD). The alternate cover test showed alternate esotropia. The secondary deviation was more than primary deviation. Motility examination revealed complete restriction of abduction of the left eye with narrowing of the palpebral fissure with downshoot on adduction [Fig. 3]. There was no binocularity on Worth 4 Dot test and on TNO test.
The proposed mechanism for the impaired ocular motility in DRS is congenital miswiring of the lateral and medial rectus muscles.1 In albinos, the visual pathway is abnormal wherein an increased proportion of fibers from the temporal retina project to the contralateral visual cortex.4 The retinostriate projections in albinism could therefore be considered miswired.4 Holmes et al.2 reported a case similar to ours of DRS and OCA in a five-year-old female. They hypothesized that the association of DRS with OCA demonstrated miswiring involving more than one neural pathway. Our report supports the view that ocular miswiring involving different neural pathways can occur with DRS. We believe that this was a chance finding as earlier thought.24
This article is financially supported by ORBIS International, India.
1. Von Noorden GK, Campos EC. Special forms of strabismus Binocular Vision and Ocular Motility. 20026th ed St Louis CV Mosby Co:458–65
2. Holmes JH, Cathleen MC. Duane syndrome associated with oculocutaneous albinism J Pediatric Ophthalmol Strabismus. 1991;28:31–4
3. Creel D. Problems of ocular miswiring in Albinism, Duane's syndrome and Marcus Gunn phenomenon Int Ophthalmol Clin. 1984;24:165–76
© 2006 Indian Journal of Ophthalmology | Published by Wolters Kluwer – Medknow
4. Morland AB, Hoffmann MB, Neveu M, Holder GE. Abnormal visual projection in a human albino studied with functional magnetic resonance imaging and visual evoked potentials J Neurol Neurosurg Psychiatr. 2002;72:523–6