Duane Syndrome

Updated: Mar 20, 2023
  • Author: Arun Verma, MD; Chief Editor: Hampton Roy, Sr, MD  more...
  • Print

Practice Essentials

Duane syndrome (DS), or Duane retraction (or co-contraction) syndrome (DRS), is a congenital restrictive strabismus that can occur either as an isolated entity or in conjunction with other congenital anomalies. It now is listed as a congenital cranial dysinnervation disorder. It is characterized by co-contraction of horizontal recti upon attempted adduction, causing globe retraction along with variable amounts of upshoots or downshoots. It may have limited abduction or adduction or both and presents as esotropic, exotropic, or orthotropic Duane.

The diagnosis of this disease is usually clinical. However, recent research has provided a greater insight into the genetic basis of this disease, paving a way for a greater role of genetics in diagnosis and management. This disease can have a variable presentation; hence, the treatment plan should be tailored to each patient.



Duane syndrome is a rare, congenital disorder of eye movement. Most individuals with Duane syndrome are diagnosed by age 10 years.

Normal eye movements

The 6 muscles that control eye movement are attached to the outside of the wall of the eye. In each eye, 2 muscles move the eye horizontally. The lateral rectus muscle pulls the eye out, toward the ear, and the medial rectus muscle pulls the eye in, toward the nose. Four other muscles move the eye up or down and at an angle. Each eye muscle receives the command for movement from cranial nerves that exit the brain.

Duane syndrome

Duane syndrome (DS) is a miswiring of the eye muscles that causes some eye muscles to contract when they should not and other eye muscles not to contract when they should. People with Duane syndrome have a limited and sometimes absent ability to move their eye outward toward the ear (ie, abduction), and in most cases, they have a limited ability to move the eye inward toward the nose (ie, adduction).

Duane syndrome. Duane syndrome.

This probably occurs around the sixth week of pregnancy and is due to poor development of tiny parts of the brainstem that control the eye muscles. In Duane syndrome, the sixth cranial nerve that controls the lateral rectus muscle (the muscle that rotates the eye out toward the ear) does not develop properly. Why the nerve does not develop is not yet understood. Thus, the problem is not primarily with the eye muscle itself but with the nerve that transmits the electrical impulses to the muscle. There is also irregular innervation of a branch from the third cranial nerve, which controls the medial rectus muscle (the muscle that rotates the eye toward the nose). This is why abnormalities may be found in both left gaze and right gaze.

Often, when the eye moves toward the nose, the eyeball also pulls into the socket (ie, retraction), and the eye opening narrows. In some cases, the eye moves upward or downward. Many patients with Duane syndrome develop a habit of turning their face to maintain binocular vision and thus compensate for improper turning of the eyes. In about 80% of all cases of Duane syndrome, only one eye is affected, most often the left eye. However, in some cases, both eyes are affected; usually, 1 eye is affected more than the other. 

An individual diagnosed with Duane syndrome in the An individual diagnosed with Duane syndrome in the left eye. In this image, the affected person is attempting to look far right. Notice the afflicted left eye faces straight and up (an "upshoot"), rather than following the right eye to the right.

In 70% of cases, Duane syndrome is an isolated condition. However, other conditions and syndromes have been associated with Duane syndrome. These include malformation of the skeleton, ears, eyes, kidneys, and nervous system, as well as the following:

  • Okihiro syndrome (an association of Duane syndrome with forearm malformation and hearing loss)
  • Wildervanck syndrome (fusion of neck vertebrae and hearing loss)
  • Holt-Oram syndrome (abnormalities of the upper limbs and heart)
  • Morning-glory syndrome (abnormalities of the optic disc or blind spot)
  • Goldenhar syndrome (malformation of the jaw, cheek, and ear, usually on one side of the face)

History of Duane syndrome

Sinclair (in 1895), Bahr (in 1896), Stilling (in 1887), Turk (in 1899), and Wolff (in 1900) first described Duane retraction syndrome (DRS). [1, 2, 3, 4, 5] In 1905, Duane reported 54 cases, summarizing all the clinical findings, reviewing previous work, and offering theories on the pathogenesis and treatment of the disease. [6]  

Duane syndrome. Duane syndrome.

Brown classified the condition into 3 subtypes, based upon clinical observations. [7] Type A corresponded to limited abduction and less limited adduction (as described originally by Duane). Type B corresponded to limited abduction but normal adduction. Type C corresponded to limitation of adduction that is greater than limitation of abduction, giving rise to a divergent deviation and a head posture in which the face is turned away from the side of the affected eye.

In 1974, with the support of electromyography (EMG) and following the suggestions of Lyle and Malbran, Huber classified Duane syndrome into the 3 types: Duane 1, Duane 2, and Duane 3. [8, 9, 10] Type 1 is marked limitation of abduction (corresponds to Type B in Brown's classification) explicable by maximum innervation reaching the lateral rectus muscle only when the affected eye is adducted. Type 2 is limitation of adduction (corresponds to Type C in Brown’s classification), which Huber explains as being caused by co-innervation of both medial and lateral rectus muscles on attempted adduction. Type 3 is limitation of both adduction and abduction (corresponds to Type A in Brown’s classification), which Huber explains as being due to co-contraction, accompanied by a loss of innervation to the lateral rectus muscle on attempted abduction.

Duane syndrome is a congenital ocular motility disorder characterized by limited abduction and/or limited adduction. The palpebral fissure narrows (ie, the globe retracts) on attempted adduction. Upward or downward deviation may occur with attempted adduction because of a leash effect. Often associated with this condition is a tether phenomenon consisting of overelevation, overdepression, or both during adduction as the retracted globe escapes from its horizontal rectus restrictions. It is a condition of aberrant innervation that results in co-contraction of the medial and lateral recti in the affected eye. Therefore, Duane syndrome can be considered to be congenital miswiring of the medial and the lateral rectus muscles such that globe retraction occurs on adduction.



Neuropathologic, neuroradiologic, and neurophysiologic data

Findings from neuropathologic, neuroradiologic, and neurophysiologic studies support the hypothesis that Duane syndrome results from an absence of cranial nerve VI (abducens nerve). Neuropathologic evidence comes from postmortem examinations of individuals who had Duane syndrome. These studies have shown an absence of cranial nerve VI and its corresponding alpha motor neurons in the pons, as well as aberrant innervation of the lateral rectus muscle by a branch of cranial nerve III.

MRI studies of an individual with Duane syndrome also revealed the absence of the abducens nerve. Neurophysiologic evidence of neuronal involvement in Duane syndrome is derived from EMG studies, which show that the medial and lateral recti muscles are electrically active in individuals with Duane syndrome. However, when individuals with Duane syndrome attempt to move their eyes inward (ie, adduct it), both of these muscles contract at the same time, causing the eyeball to retract inward and the eye opening (palpebral fissure) to become narrowed. These findings support aberrant innervation of the lateral rectus muscle.

Autopsy specimens have shown agenesis of the sixth nerve nucleus and innervation of the lateral rectus muscle by the third nerve nucleus. This observation explains the globe retraction on attempted adduction. In neuropathologic terms, the cause of Duane syndrome is an absent sixth nerve nucleus and innervation of the lateral rectus by a branch of the inferior division of the third nerve.

Condensation of the mesoderm around the eye results in development of the extrinsic eye muscles. When the embryo is 7 mm long, they form 1 mass, which is supplied by only the third nerve. When the embryo is 8-12 mm long, that is, when the fourth nerve and the sixth nerve arrive, this mass divides into separate muscles. Because of an absence of or an aplasia of the abducens nerve, a branch of the oculomotor nerve (as a substitute) conceivably enters the part of the muscle mass that is to become the lateral rectus muscle.

Given the evidence that Duane syndrome results from an absence of the abducens nerve (cranial nerve VI) and that Duane syndrome is associated with other anomalies in some cases, Duane syndrome is thought to reflect a disturbance of normal embryonic development. Either a genetic factor or an environmental factor may be involved when the cranial nerves and ocular muscles are developing at 3-8 weeks of gestation.

The association of Duane syndrome with other ocular anomalies and congenital facial, skeletal, or neural abnormalities in 30-50% of patients further substantiates the hypothesis of disturbed embryogenesis. A teratogenic event during the second month of gestation seems to cause most ocular and extraocular abnormalities observed in combination with Duane syndrome. Duane syndrome is present from birth, even if it is not recognized during infancy. An abnormal head posture and strabismus are often visible in old photographs taken in early childhood.

Genetic and environmental factors

The genetic basis of Duane syndrome is being studied, but genetic loci for Duane syndrome have not. Similar to congenital fibrosis of the extraocular muscles (CFEOM), Duane syndrome is classified as strabismus, under the subclassification of incomitant strabismus and extraocular muscle fibrosis syndromes. Although the term muscle fibrosis suggests that syndromes under this heading are primary disorders of muscle, evidence suggests that Duane syndrome (and other syndromes under this heading, including CFEOM) may be primary disorders of nerve innervation. A review of fibrosis syndromes can be found in Engle's article in 1998. [11]

Both genetic factors and environmental factors are likely to play a role in the development of Duane syndrome. Most cases of Duane syndrome cases are sporadic, with only approximately 2-5% of patients having a familial pattern; families with large involvement are rarely reported. Both dominant forms and recessive forms of Duane syndrome have been documented. In some families with dominant Duane syndrome, the disease skips a generation (reduced penetrance) and ranges in severity (variable expressivity). Most familial cases are not associated with other anomalies.

Genetic linkage studies of a large family with Duane syndrome established the location of a Duane syndrome gene on chromosome 2. Although a genetic cause of Duane syndrome has long been accepted, these studies were the first to show a statistically significant linkage. In addition, cytogenetic results of individuals with Duane syndrome have shown, in rare cases, abnormalities that suggest the contribution of more than 1 gene. Deletions on chromosomes 4 and 8 and an extra marker chromosome thought to be derived from chromosome 22 have been documented in individuals with Duane syndrome.

Familial occurrence with dominant inheritance patterns has been reported. Duane syndrome has also been described in monozygotic twins. However, most cases are sporadic rather than familial. Pairs of identical twins with mirror-image Duane syndrome have been described. Its most common variant (type 1, 85%) and most commonly manifests in the left eye (60%) and in girls (60%) as severely limited or absent abduction. In 90% of cases, the patient has no family history of Duane syndrome. Ten percent of patients will have an affected family member, and these tend to be cases where both eyes are involved. There is currently no test that can determine whether a patient has a hereditary form.

In a demographical and clinical profile based on 441 cases, Kekunnaya et al concluded that unilateral and bilateral Duane syndrome show considerable differences in gender distribution, associated ocular deviation, overshoots, and ocular and systemic associations. [12]

See also the Causes section.




United States

The frequency of Duane syndrome in the general population of individuals with eye movement disorders (strabismus) is approximately 1-5%. The most common clinical presentation is type 1 Duane syndrome (70-80%), followed by type 2 (7%) and type 3 (15%). Involvement of both eyes is less common than involvement of one eye only. Approximately 80% of cases are unilateral. Of the unilateral cases, the left eye most often is affected (60-72%).


Duane syndrome accounts for 1% of all cases of strabismus. Unilateral retraction syndrome is the rule; the left eye is distinctly involved in 60% of cases, the right eye is involved in 20% of cases, and both eyes are involved in 20% of cases.


About 40% of patients with Duane syndrome develop esotropia and tight medial rectus muscles; therefore, they adopt a head turn toward the eye to maintain single binocular vision, or they maintain a straight head but accept esotropia, abnormal retinal correspondence (ARC), and suppression, if available.

In about 30% of patients, compensatory head positions are necessary to achieve binocular single vision. Before surgery is contemplated, coexisting and clinically significant refractive errors, anisometropia, and amblyopia must be treated. Kirkham found that amblyopia was present in 21% of his patients with Duane syndrome, and nearly 50% had anisometropia. [13] In 2 large series, the incidence of amblyopia in patients with Duane syndrome was 10% and 14%, respectively. However, Maruo and coworkers found a 3.6% prevalence of amblyopia among 220 patients with Duane syndrome. [14] Tredici and von Noorden also reported a 3% incidence of amblyopia in 72 patients and commented that this incidence is similar to that in the general population. [15, 16]


Duane syndrome has no reported racial preference.


The female-to-male ratio is 3:2, but this female predominance is not understood.


Duane syndrome is a congenital anomaly. Most cases are diagnosed by age 10 years.



Duane syndrome represents a spectrum of motility disorders in which the common feature is retraction of the affected eye on attempted adduction. Because the affected sixth cranial nerve cannot be repaired or replaced, there is no cure for Duane syndrome. However, for people whose lives are significantly disrupted by the condition, surgery can be very helpful in reducing or stopping the abnormal head posture many develop in an attempt to see better. Electrophysiologic and neuropathologic studies have shown that the underlying cause is anomalous innervation of the lateral rectus with the medial rectus and, at times, with vertical muscles in the affected eye. Clinical abnormalities observed in Duane syndrome can include any or all of the following: a deviation in the primary position; abnormal head position; severe retraction causing a pseudoptosis; and upshoots and/or downshoots associated with A, V, or X patterns. A surgical approach based on the analysis of these 4 features is presented, allowing the surgeon to devise an appropriate, individualized plan for a given case, which can yield optimal results in 1 operation.

This disorder consists of deficient horizontal eye movements, eyelid retraction, palpebral fissure narrowing, and abnormal vertical eye movements. Most cases are sporadic and unilateral (usually left side) with a slight female predominance. Several associated ocular and systemic conditions have been described in patients with Duane syndrome. In most cases, the abducens nucleus and nerve are absent or hypoplastic, and the lateral rectus muscle is innervated by a branch of the oculomotor nerve. However, there may be contributing mechanical abnormalities. Type I Duane syndrome (primary gaze position esotropia with limitation of abduction) comprises most cases. Approximately 50% of patients with type I Duane syndrome are orthophoric in primary gaze. Esotropia is the most common type of strabismus encountered, and characteristic upshoots and downshoots occur in adduction. Surgical intervention has gradually become more popular in order to improve the primary gaze alignment and mitigate some of the associated abnormalities in ocular motility. However, patients rarely are rendered clinically healthy, and limited expectations are appropriate.

The prognosis of surgery is not good; therefore, it is best to avoid surgery if patients have some form of binocular vision.


Patient Education

Patients must be taught to learn some form of head tilt and orthoptic training to have some binocular vision.