Isolated Duane Retraction Syndrome, often simply called Duane syndrome (DS), is a congenital disorder of eye motility where one or both eyes have difficulty moving outward (abduction) or inward (adduction) and may retract (pull back) into the socket when trying to turn. It is caused by abnormal development of the cranial nerves that control eye movement, particularly the sixth cranial nerve.

In Duane syndrome, the sixth cranial nerve and its nucleus in the brainstem either fail to develop properly or are absent altogether. This means the lateral rectus muscle never receives its correct nerve signal. To compensate for this missing connection, the body creates an abnormal “miswiring.” A rogue branch from the third cranial nerve (the oculomotor nerve) which is normally responsible for moving the eye inward, upward, and downward, grows over and attaches to the lateral rectus muscle as well.

This aberrant wiring leads to a paradoxical situation:

• When the brain sends a signal to look inward (activating the third nerve), both the medial rectus (the “inward-pulling” muscle) and the lateral rectus (the “outward-pulling” muscle) are told to contract at the same time.
• When the brain sends a signal to look outward, the lateral rectus muscle receives no signal and cannot contract.

This co-contraction of opposing muscles is what causes the unique and characteristic signs of the syndrome. The term “retraction” refers to the fact that when the inward- and outward-pulling muscles fire simultaneously, they pull the eyeball backward into the socket. “Isolated” means the condition occurs without any other neurological or systemic abnormalities.

In my experience, many parents notice something is off when their child’s eyes don’t move together or one eyelid narrows during side gazes, often during a routine pediatric visit.

Analogy: Imagine the eye muscles as puppet strings controlled by specific nerves. In DRS, one of the key strings is missing or miswired, so the eye can’t move freely, and sometimes pulls back or “tugs” when trying to look in certain directions.

Duane syndrome is caused by a disruption that occurs during a critical period of early embryonic development, typically between the third and eighth week of gestation. This is the time when the intricate neural circuits for the cranial nerves and the eye muscles are forming.

The specific developmental error is the failure of the sixth cranial nerve nucleus to form properly. This leads to the absence of the abducens nerve, which then results in the subsequent “miswiring” of the lateral rectus muscle by a branch of the third cranial nerve. The exact trigger that causes this developmental anomaly is mostly unknown. Parents do not cause it by any action or inaction during pregnancy.

Parents often ask if they did something wrong during pregnancy, I always reassure them that DRS is a developmental condition and no one is to blame.

DRS is a congenital (present at birth) condition and not acquired later in life. Its origin is almost always genetic, although it is not typically inherited in a simple pattern.

Sporadic Occurrence

In approximately 90% of cases, Duane syndrome is sporadic. This means it occurs by chance in an individual with no other affected family members. It is believed to be the result of a de novo (new) genetic mutation that arises spontaneously during the formation of the reproductive cells or in early development.

Familial Inheritance

In about 10% of cases, Duane syndrome is familial and is passed down through generations. When it is inherited, it most often follows an autosomal dominant pattern. This means that an individual only needs to inherit one copy of the mutated gene from one parent to have the condition. An affected parent has a 50% chance of passing the condition on to each of their children. Researchers have identified mutations in several genes, particularly the CHN1 gene, that are responsible for some familial cases of Duane syndrome (NIH Genetic and Rare Diseases Information Center [GARD], 2017).

Associated Syndromes

While this article focuses on isolated Duane syndrome, it is important to note that it can sometimes be a feature of a broader genetic syndrome that affects other parts of the body. These can include Goldenhar syndrome (which affects facial, ear, and spinal development), Holt-Oram syndrome (affecting the heart and upper limbs), and others. When a child is diagnosed with Duane syndrome, a doctor will perform a thorough physical examination to look for any other signs that might suggest a wider syndrome.

Clinically, I’ve seen that most cases are spontaneous and not inherited, but it’s always wise to assess for any subtle family history or associated syndromes.

Symptoms of DRS vary by type and severity. The condition is more common in the left eye than the right and occurs more frequently in females (American Association for Pediatric Ophthalmology and Strabismus [AAPOS], n.d.).

The classic signs and symptoms that define the syndrome include:

• Limited Abduction: This is the primary and most consistent feature. The affected eye has difficulty or a complete inability to move outward, toward the ear.
• Globe Retraction on Adduction: When the person tries to look inward toward their nose, the eyeball visibly pulls back (retracts) into the eye socket. This is a hallmark sign caused by the co-contraction of the medial and lateral rectus muscles.
• Palpebral Fissure Narrowing: As the eyeball retracts, the eyelid opening (the palpebral fissure) narrows, making the eye appear smaller.
• Upshoots and Downshoots: In some cases, as the eye moves inward, it may also shoot suddenly upward or downward.
• Compensatory Head Posture: This is a very common and important adaptive strategy. To avoid the range of motion where the eye movements are abnormal and to maintain binocular vision (using both eyes together), an individual will often adopt a slight face turn toward the side of the affected eye.
• Strabismus: The eyes may be misaligned (crossed or drifted out) when looking straight ahead.

Despite these unusual eye movements, it is crucial to understand that in most cases of isolated Duane syndrome, the vision in each eye is excellent, especially when using their compensatory head turn.

In the clinic, I’ve often seen children unconsciously turning their heads when tracking objects, helping to maintain single vision despite limited eye mobility.

DRS is diagnosed based on clinical signs and specialized eye movement testing.No single lab test confirms it, but careful evaluation by an ophthalmologist or pediatric eye specialist is crucial. During the examination, the doctor will have the patient follow a light or a toy in all directions of gaze. This allows the doctor to document the key findings:

• Limited ability to move the eye outward (abduction).
• Eyeball retraction into the socket when looking inward (adduction).
• The narrowing of the eyelid opening on adduction.
• Any associated upshoots or downshoots.

Based on the specific pattern of these movements, Duane syndrome is often classified into three main types (Huber’s Classification):

• Type 1: This is the most common type. There is a marked limitation of abduction (outward movement), with relatively normal adduction (inward movement).
• Type 2: This is rare. There is a limitation of adduction, with normal or only slightly limited abduction.
• Type 3: There is a limitation of both abduction and adduction.

An ophthalmologist will also perform a complete eye exam, including checking vision and performing a dilated exam to ensure the overall health of the eyes is normal. In my practice, detailed eye movement testing is usually enough to make the diagnosis. MRIs are reserved for complex or atypical cases.

There is no cure for Duane syndrome. Therefore, the goals of management are not to fix the abnormal movements, but rather to:

• Ensure that good vision develops in both eyes.
• Address any significant and cosmetically noticeable eye misalignment.
• Eliminate an uncomfortable or functionally limiting head turn.

1. Observation

For the vast majority of individuals with Duane syndrome, the recommended management is simply observation. If the person has good vision in both eyes, no significant eye misalignment when looking straight ahead, and only a minor or no head turn, then no intervention is needed. Regular eye exams throughout childhood are recommended to monitor vision.

2. Corrective Eyeglasses

Glasses may be prescribed to correct any underlying refractive errors, such as nearsightedness, farsightedness, or astigmatism. Ensuring each eye has the clearest possible vision is crucial for preventing amblyopia (“lazy eye”). In some cases, special prisms can be incorporated into the glasses to help manage a small eye misalignment.

3. Amblyopia Treatment

If one eye is found to have weaker vision than the other (amblyopia), treatment will be initiated to strengthen the weaker eye. This typically involves patching the stronger eye for a certain number of hours each day or using atropine eye drops to temporarily blur the vision in the stronger eye.

4. Eye Muscle Surgery (Strabismus Surgery)

Surgery is reserved for a minority of patients who have a significant problem that is impacting their function or appearance. It is imperative to have realistic expectations for surgery. The primary indications for surgery are:

• To correct a significant and cosmetically noticeable eye misalignment (strabismus) when looking straight ahead.
• To eliminate a large and functionally or cosmetically problematic compensatory head posture.
• To fix a severe and bothersome upshoot or downshoot of the eye.

The surgical procedure involves carefully repositioning one or more of the eye muscles to better balance the forces acting on the eye in its primary, straight-ahead position. This can improve alignment and reduce the need for a head turn, but the abnormal movements on side gaze will persist.

I always reassure families that surgery, when needed, is typically safe and targeted, aimed more at alignment and comfort than restoring full motion.

Duane Retraction Syndrome is a fascinating congenital condition that results from a permanent “miswiring” of the nerves that control eye movement. While the abnormal movements can be surprising, it is, in its isolated form, a benign and non-progressive disorder. The vast majority of people with Duane syndrome have excellent vision, adapt well to their unique eye motility, and require no treatment at all beyond regular eye check-ups. For those with a significant eye misalignment or an uncomfortable head posture, eye muscle surgery can be very successful at improving alignment and function. Parents often feel reassured to know that with proper care, children with DRS grow up seeing the world just fine, sometimes from a slightly different angle, but with clarity and confidence.

American Association for Pediatric Ophthalmology and Strabismus (AAPOS). (n.d.). Duane Syndrome. Retrieved from https://aapos.org/glossary/duane-syndrome

National Institutes of Health, Genetic and Rare Diseases Information Center (GARD). (2017). Duane retraction syndrome. Retrieved from https://rarediseases.info.nih.gov/diseases/6249/duane-retraction-syndrome

National Organization for Rare Disorders (NORD). (2021). Duane Syndrome. Retrieved from https://rarediseases.org/rare-diseases/duane-syndrome/