From the Guidelines
Duane syndrome is a rare congenital eye movement disorder characterized by limited horizontal eye movement, typically affecting one eye, as noted in recent studies 1. Key points about Duane syndrome:
- Diagnosis: Usually made in childhood based on eye movement examination.
- Symptoms: Limited or absent ability to move the affected eye outward (abduction) and/or inward (adduction), narrowing of the eye opening when looking inward, and possible head turning to compensate.
- Treatment options:
- Observation: Mild cases may not require intervention.
- Glasses or contact lenses: To correct any associated refractive errors.
- Prism glasses: To help align images and reduce double vision.
- Eye muscle surgery: In severe cases, to improve eye alignment and reduce abnormal head posturing.
- Management:
- Regular eye exams to monitor progression and associated conditions.
- Amblyopia (lazy eye) treatment if present, typically with patching or atropine drops.
- Addressing any neck or back pain from compensatory head postures.
- Prognosis: Generally good, with most patients adapting well to the condition. Duane syndrome results from abnormal development of the sixth cranial nerve and associated eye muscles during fetal development, as mentioned in the study 1. This leads to miswiring of the lateral rectus muscle, causing the characteristic eye movement limitations. Understanding this helps explain why the condition is present from birth and why treatment focuses on managing symptoms rather than correcting the underlying cause. The most recent and highest quality study, 1, provides the most relevant information on Duane syndrome, which is essential for making informed decisions about diagnosis, treatment, and management.
From the Research
Definition and Characteristics of Duane Syndrome
- Duane syndrome is a congenital disorder of eye movement characterized by partial or absent development of the sixth cranial nerve nucleus and/or the sixth nerve itself 2.
- It is a restrictive congenital strabismus characterized by variable horizontal duction deficits with globe retraction and shoots on attempted adduction and narrowing of the palpebral aperture 3.
- The disease is usually unilateral with female preponderance 3.
Etiopathogenesis
- The basic etiopathogenesis involves dysinnervation of the lateral rectus (LR) due to aplastic/hypoplastic abducens nucleus with a secondary aberrant supply to the LR by the medial rectus (MR) subnucleus of the oculomotor nerve 3.
- The etiopathogenesis can also be explained by a spectrum of mechanical, innervational, neurologic and genetic abnormalities occurring independently or which influence each other giving rise to patterns of clinical presentations along with a complex set of ocular and systemic anomalies 4.
Classification and Management
- Duane syndrome can be classified into different types, including Huber type I, II, and III, based on the clinical presentation 4.
- The management of Duane syndrome is challenging and must be individualized based on the amount of ocular deviation, abnormal head position, associated globe retraction and overshoots 3, 4.
- Surgical approaches, including differential recessions of the lateral and MR muscles, Y-split or periosteal fixation of the LR muscles, and surgery on the normal eye, can be used to correct esotropia or exotropia, globe retraction, and shoots 3, 5.
Genetic Associations
- Duane syndrome can be coinherited with radial ray anomalies as an autosomal dominant trait, referred to as "Okihiro syndrome" or "Duane radial ray syndrome" (DRRS) 6.
- The disease gene for DRRS has been mapped to a region of chromosome 20 and mutations in the SALL4 gene have been identified as a cause of the syndrome 6.