Duane syndrome is an eye movement disorder present at birth (congenital) characterized by horizontal eye movement limitation: a limited ability to move the eye inward toward the nose (adduction), outward toward the ear (abduction), or in both directions. When the affected eye(s) moves inward toward the nose, the eyeball retracts (pulls in) and the eye opening (palpebral fissure) narrows. In some patients, when the eye attempts to look inward, it moves upward (upshoot) or downward (downshoot).
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| Duane's syndrome |
Duane syndrome falls under the larger heading of strabismus (misalignment of the eyes) under the sub-classification of incomitant strabismus (misalignment of the eyes that varies with gaze directions) and subheading of what was previously termed extraocular fibrosis syndromes (conditions associated with fibrosis of the muscles that move the eyes), now termed congenital cranial dysinnervation disorders (CCDDs).
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| Duane's syndrome |
More details: 📖 Neuro-Ophthalmology 3th Edition
The CCDDs are a group of congenital neuromuscular diseases resulting from developmental errors in innervation; the abnormalities involve one or more cranial nerves/nuclei with absence of normal innervation and/or secondary aberrant innervation. The group includes Duane syndrome, congenital fibrosis of the extraocular muscles, congenital ptosis, Marcus Gunn jaw winking, Möbius syndrome, crocodile tears, horizontal gaze palsy and congenital facial palsy, but this is not an exhaustive list.
Duane syndrome has been subdivided clinically into three types: type 1, type 2, and type 3.
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| Duane syndrome has been subdivided clinically into three types: type 1, type 2, and type 3. |
Duane syndrome type 1: The ability to move the affected eye(s) outward toward the ear (abduction) is limited, but the ability to move the affected eye(s) inward toward the nose (adduction) is normal or nearly so. The eye opening (palpebral fissure) narrows and the eyeball retracts into the orbit when looking inward toward the nose (adduction). When looking outward toward the ear (abduction), the reverse occurs.
Duane syndrome type 2: The ability to move the affected eye(s) inward toward the nose (adduction) is limited, whereas the ability to move the eye outward (abduction) is normal or only slightly limited. The eye opening (palpebral fissure) narrows and the eyeball retracts into the orbit when the affected eye(s) attempts to look inward toward the nose (adduction).
Duane syndrome type 3: The ability to move the affected eye(s) both inward toward the nose (adduction) and outward toward the ear (abduction) is limited. The eye opening narrows and the eyeball retracts when the affected eye(s) attempts to look inward toward the nose (adduction).
Each of these three types has been further classified into three subgroups designated A, B, and C to describe the eyes when looking straight (in primary gaze). In subgroup A, the affected eye is turned inward toward the nose (esotropia). In subgroup B, the affected eye is turned outward toward the ear (exotropia), and in subgroup C, the eyes are in a straight primary position.
Different clinical types may be present within the same family, suggesting that the same genetic defect may produce a range of clinical presentations.
The most common clinical presentation is type 1 DS (78% of cases) followed by type 3 (15%) and type 2 (7%). Involvement of both eyes (bilateral) is less common than involvement of one eye only (unilateral). Approximately 80-90% of cases are unilateral. Of the unilateral cases, the left eye is more often affected (72%). Amblyopia (reduced visual acuity in an eye) due to a lack of binocular vision occurs in about 10% of DS cases and is more common in familial autosomal dominant CHN1 gene familial cases.
Duane syndrome is usually an isolated finding (approximately 70%), but may be associated with other malformations. Major anomalies associated with DS can be grouped into five categories: skeletal, auricular (having to do with the ears), ocular (having to do with the eyes) and neural (having to do with the nervous system) and renal (having to do with the kidneys and urinary tract).
Alexander Duane (1858 - 1926), American ophthalmologist.
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| Alexander Duane |
Alexander Duane was one of the first investigators in ophthalmology with a special interest in accommodation and squint. He was born into a prominent family in Molone, New York. His father was the army general James Duane and his boyhood was spent moving between various postings. He was educated at the Union College, Cincinnati, where he gained many academic rewards and thereafter studied medicine at the College of Physicians and Surgeons, New York, which later became the medical school of Columbia University.
After graduation in 1881 Duane interned at the New York Hospital and was educated in eye medicine by the German-born American ophthalmologist Hans Jakob Knapp (1832-1911). He specialised in this discipline and commenced ophthalmological practice in New York in 1884. For a brief period he taught ophthalmology at the Cornell University.
During his boyhood his mother, a woman of considerable literary abilities, gave him extensive instruction in the English language. He put this knowledge to use during his internship when he developed an interest in lexicography and supplied medical terms for several standard dictionaries. Duane also received training in mathematics from his father and he applied these skills to an analysis of the movements of the extraocular muscles, publishing a classic account of motor abnormalities in 1896.
His work in this field, together with his investigations of accommodation and refraction, represent his great contribution to the science of ophthalmology. Still, perhaps, he was most noted for his translations of the textbook by the Viennese authority Ernst Fuchs, which appeared in English in 1903 under the title of Fuchs Textbook of Ophthalmology and ran into eight editions.
During the Spanish-American War Duane served in the US Navy as a signal officer, and in the Great War on the American ship Granite State. He was also the author of a monograph entitled Rules for signalling on land and sea which was first published in 1899.
Duane received an honorary doctorate of science from his university and was elected chairman of the ophthalmological section of the American Medical Association in 1917.
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