advertisement
17 August 2011

Duane syndrome

Duane syndrome is a congenital condition that affects the eye muscles, making it difficult for a person to move his/her eyes. Normally, the outward wall of each eye is attached to six different muscles. These muscles are attached (wired) to nerves, and the brain controls eye movements by sending messages to the eye muscles through these nerves. In patients with Duane syndrome, the nerves are not properly attached to one or more of the eye muscles, so the brain cannot fully control movement of the eye.

0

BACKGROUND

Duane syndrome is a congenital condition that affects the eye muscles, making it difficult for a person to move his/her eyes. Normally, the outward wall of each eye is attached to six different muscles. These muscles are attached (wired) to nerves, and the brain controls eye movements by sending messages to the eye muscles through these nerves. In patients with Duane syndrome, the nerves are not properly attached to one or more of the eye muscles, so the brain cannot fully control movement of the eye.

Patients may have difficultly moving one or both eyes inwards (closer to the nose) or outwards (toward the ear). Some patients with Duane syndrome may exhibit strabismus, which is a misalignment of the eyes that causes the eyes to always appear to be pointing in different directions. Also, some patients may experience ambylopia (or lazy eye), which is poor or indistinct vision in the affected eye.

Miswiring of the eye muscles is thought to occur during embryonic development. Therefore, patients with Duane syndrome are born with the condition and usually exhibit symptoms soon after birth. For unknown reasons, the left eye appears to be affected more frequently than the right eye in patients with Duane syndrome. In 20% of Duane syndrome cases, the movement of both eyes is affected.

In some cases, medical problems not related to vision may occur in patients with Duane syndrome. These include loss of hearing, improper development of the vertebrae or spine, Goldenhaar syndrome (a defect involving developmental deformities of the face), or Holt-Oram syndrome (an abnormality of the upper limbs and heart).

Currently, there is no known cure for Duane syndrome. However, most patients with Duane syndrome are able to live normal, productive lives. Some patients with Duane syndrome may choose to undergo eye surgery, which may be effective in reducing the severity of the symptoms. Physical therapy, such as eye exercises, may also be helpful for some patients.

RISK FACTORS

For unknown reasons, females appear to be at higher risk for developing Duane syndrome than males. About 60% of patients with Duane syndrome are female and 40% are male.

For unknown reasons, the left eye of patients with Duane syndrome appears to be affected more frequently than the right eye. In 20% of patients with Duane syndrome, the movement of both eyes is affected.

The majority of cases (about 90%) of Duane syndrome do not appear to be inherited, meaning that the patient has no family history of the condition. No specific gene or mutation has yet been associated with Duane syndrome.

CAUSES

Normally, the outward wall of each eye is attached to six different muscles. These muscles are attached to nerves, and the brain controls eye movements by sending messages to the eye muscles through these nerves. In patients with Duane syndrome, the nerves are not properly attached to one or more of the eye muscles, so the brain cannot fully control movement of the eye.

Patients with Duane syndrome may have defects in the nerve (called the sixth cranial nerve) that connects to the lateral rectus muscle, which controls outward eye movement (abduction). Patients may also have defects in the nerve that connects to the medial rectus muscle, which controls inward eye movement (adduction). In both cases, it appears that the nerves have not developed properly, so they are not able to send messages to the eye muscles.

It is not yet clear what causes the developmental defects in the nerves of patients with Duane syndrome. The majority of cases (about 90%) of Duane syndrome do not appear to be inherited, meaning that the patient has no family history of the condition. No specific gene or mutation has yet been associated with Duane syndrome.

SIGNS AND SYMPTOMS

Duane syndrome is a condition that affects the eye muscles, making it difficult for a patient to move the eyes. Patients with Duane syndrome are born with the condition and usually exhibit symptoms from birth.

Patients may have difficulty moving one or both eyes inwards (closer to the nose) or outwards (toward the ear). Some patients are completely unable to perform an outward eye movement, and when an inward movement occurs, the eye may retract into the socket. Also, some patients may exhibit an elevation or "upshot" of the affected eye.

For unknown reasons, the left eye appears to be affected more frequently than the right eye in patients with Duane syndrome. In 20% of Duane syndrome cases, the movement of both eyes is affected.

Some patients with Duane syndrome may exhibit strabismus, which is a misalignment of the eyes that causes the eyes to always appear to be pointing in different directions. Patients with Duane syndrome may also experience reduced vision or narrowing of the eyelid in the affected eye or eyes and some patients may experience ambylopia (or lazy eye), which is poor or indistinct vision in the affected eye.

Patients with Duane syndrome may appear to hold their heads in abnormal positions. This is usually done by the patient in an effort to keep the eyes straight.

DIAGNOSIS

Diagnosis of Duane syndrome is typically made during a routine eye exam by an eye doctor, such as an ophthalmologist. Patients with Duane syndrome are born with the condition and usually exhibit symptoms from birth. An abnormal head position and an inability to move the eyes outward or inward are the main signs that are used to diagnose the condition. Doctors may examine the range of eye motion and check for other features that are associated with Duane syndrome, such as strabismus, nystagmus, or retraction of the eyeball (when the eye pulls into the socket). In some cases, a noninvasive imaging procedure called magnetic resonance imaging (MRI) may be used to assist in the diagnosis. MRI can be used to detect defects in the sixth cranial nerve. Diagnosis is typically made by the time patient is 10 years old.

COMPLICATIONS

In some patients with Duane syndrome, the symptoms may be very mild and require no intervention. It is not clear why other abnormalities sometimes develop in patients.

Nystagmus: Some patients may experience involuntary eye movements (such as shaking or wobbling), which is referred to as nystagmus.

Cataract: A cataract, which is a clouding or opaqueness of the eye lens, may develop in some patients.

Microphthalmos: Microphthalmos (abnormal smallness of one or both eyes) may affect some patients with Duane syndrome.

Coloboma: Some patients may be born with a hole (called a coloboma) in one of the structures of the eye, such as the iris or the lens. However, this does not appear to be a common complication of Duane syndrome.

Non-ocular conditions: In about 30% of patients with Duane syndrome, medical problems not related to vision may occur. It is not clear why these abnormalities develop. These include loss of hearing, improper development of the vertebrae or spine, Goldenhaar syndrome (a defect involving developmental deformities of the face), or Holt-Oram syndrome (an abnormality of the upper limbs and heart).

TREATMENT

Currently, there is no known cure for Duane syndrome. However, most patients with Duane syndrome are able to live normal, productive lives.

Glasses: Special glasses are available that contain prisms in the lenses that can redirect light to the eye. These glasses may help eliminate the need for patients to maintain abnormal head positions.

Mirrors: Additional mirrors may be installed on a patient's vehicle to assist when driving.

Exercises: Physical therapy, such as eye exercises, may be helpful for some patients to achieve better alignment of the eyes.

Surgery: In some cases, patients with Duane syndrome may choose to undergo surgery, especially in order to treat strabismus or to reduce the need to maintain abnormal head positions. In the surgery, the eye muscles that are still functioning properly are readjusted to compensate for the muscles that are not working. Although surgery can not completely restore normal eye function, it can reduce the severity of the symptoms. Surgery can be performed for functional reasons (to restore alignment), and it may also be done for cosmetic reasons (to improve appearance).

INTEGRATIVE THERAPIES

Currently, there is a lack of scientific data on the use of integrative therapies for the treatment or prevention of Duane syndrome.

PREVENTION

There are currently no known ways to prevent Duane syndrome. However, treatments exist that may help manage the symptoms of Duane syndrome.

AUTHOR INFORMATION

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

  • American Association for Pediatric Ophthalmology and Strabismus. www.aapos.org. Accessed February 27, 2008.
  • Britt MT, Velez FG, Velez G, et al. Vertical rectus muscle transposition for bilateral Duane syndrome. J AAPOS. 2005 Oct;9(5):416-21. View abstract
  • Marshman WE, Dawson E, Neveu MM, et al. Increased binocular enhancement of contrast sensitivity and reduced stereoacuity in Duane syndrome. Invest Ophthalmol Vis Sci. 2001 Nov;42(12):2821-5. View abstract
  • National Human Genome Research Institute. www.genome.gov. Accessed February 27, 2008.
  • Natural Standard: The Authority on Integrative Medicine. www.naturalstandard.com. Copyright © 2008.
  • Optometrists Network. www.optometrists.org. Accessed February 27, 2008.
  • Parsa CF, Grant E, Dillon WP Jr, et al. Absence of the abducens nerve in Duane syndrome verified by magnetic resonance imaging. Am J Ophthalmol. 1998 Mar;125(3):399-401. View abstract
  • Rao VB, Helveston EM, Sahare P. Treatment of upshoot and downshoot in Duane syndrome by recession and Y-splitting of the lateral rectus muscle. J AAPOS. 2003 Dec;7(6):389-95. View abstract
  • Sprunger DT. Recession of both horizontal rectus muscles in Duane syndrome with globe retraction in primary position. J AAPOS. 1997 Mar;1(1):31-3. View abstract


Copyright © 2011 Natural Standard (www.naturalstandard.com)
 
advertisement

Get a quote

advertisement

Read Health24’s Comments Policy

Comment on this story
0 comments
Add your comment
Comment 0 characters remaining

Live healthier

Knee pain relief »

Knee injuries Test your knee pain knowledge Symptoms of knee pain

Do you suffer from knee pain?

Do you suffer from recurrent knee pain? It could be osteoarthritis...

Vitamin wise »

Vitamins for HIV What to eat for vitamin B? Cut down on vitamins

Get your vitamins right

Find out which vitamin to use for which condition. Ask our Vitamin expert.