Duane syndrome: Eye movement disorder

About 1 in 25-100 children with strabismus suffer from the rare condition “Duane’s syndrome”, also called “congenital retraction syndrome”. A patient with this syndrome has an eye movement disorder that prevents him from looking properly to the right or left with his eye or eyes. This often results in strabismus or abnormal head posture. The cause is still unknown; in some cases the condition is hereditary. Duane syndrome is present from birth, even if people do not recognize it during toddlerhood.

  • Epidemiology Duane syndrome
  • Forms
  • Cause of eye movement disorder
  • Symptoms of eye movement disorder
  • Symptom condition
  • Diagnosis and examinations
  • Therapy
  • Heredity
  • Prognosis

Epidemiology Duane syndrome

It is difficult to put a figure on the incidence of Duane syndrome because many children with the syndrome are probably not known to an ophthalmologist or pediatric neurologist. Perhaps 1 in 25-100 children with strabismus has Duane syndrome. Women are affected more often than men (3:2 ratio). The left eye has a higher involvement than the right eye; the cause for this is unknown. Both eyes are affected in approximately 20% of patients. The condition occurs in all races and ethnic groups, with no higher frequency anywhere. Finally, children with congenital abnormalities are more likely to have Duane syndrome.

Forms

Duane syndrome has three types that occur to varying degrees. The changing size of the palpebral fissures and the failure to turn one or both eyes properly are characteristic of all forms.

  • Type 1: Mainly a problem with turning the eye outward: Occurs in 6 out of 10 children.
  • Type 2: Mainly a problem with turning the eye inwards: Occurs in 3 in 10 children.
  • Type 3: Mainly problems with turning the eye in and out: Occurs in less than 1 in 10 children.

Cause of eye movement disorder

The third and sixth cranial nerves that control eye movements do not work properly together in Duane syndrome. In the first months of pregnancy, when the eye muscles are also being formed, a developmental disorder occurs in the development of the sixth cranial nerve, which is responsible for the eye muscle that turns the eye outward. Instead of the sixth cranial nerve, the eye muscle is now controlled by the third cranial nerve, which normally only provides the muscle that turns the eye inward (toward the nose). Subsequently, one or more eye muscles do not work properly at birth because the brain is not controlled properly. This causes an eye movement disorder that affects the eye movements in the horizontal plane and the palpebral fissure.

Symptoms of eye movement disorder

When a baby is small, the symptoms are usually not immediately noticeable. But when children are a few months old and start looking around, that is the case. Yet it often happens that the ophthalmologist only makes the diagnosis when a child is already several years old and then comes to an ophthalmologist or pediatric neurologist with strabismus, which is known in medical terms as “strabismus”. Sometimes Duane syndrome involves other abnormalities; therefore, children often receive a number of additional examinations. Despite the fact that there are some symptoms, the patient rarely has any complaints. More often, the environment notices that something is wrong.

Possible symptoms

  • Abnormal position of the eye: Usually when looking to the side
  • Abnormalities of the radius bone in the forearm
  • Amblyopia: Lazy eye (best requiring treatment at a young age)
  • Restriction of eye movements (one or both eyes): Usually in a horizontal direction but sometimes also in a vertical direction (due to poor development of the sixth cranial nerve)
  • Palpebral fissure narrowing or widening: The affected eye appears smaller than the other eye when looking to the side
  • Poorer vision: Image in the corner of the eye is not always visible
  • Strabismus: Strabismus
  • Torticollis (crooked neck with abnormal head position) or moving head: In response to the abnormal eye position or avoiding double vision (diplopia) to view comfortably. Over time, this causes a sore neck and stiff neck.
  • Spinal abnormalities in the neck

In combination with other eye conditions

Sporadically, Duane syndrome occurs in combination with other eye conditions such as:

  • Cataract
  • Microphthalmia (abnormally small eye)
  • Nystagmus: Involuntary back and forth movements of the eyeball
  • Optic nerve abnormalities
  • Tearing eyes.

Symptom condition

Patients with Duane syndrome usually have no other physical complaints other than ocular problems, but 3 in 10 children still have:

  • the Goldenhar syndrome
  • the Holt-Oram syndrome
  • the morning glory syndrome
  • the Okihiro syndrome
  • the Wildervanck syndrome
  • back and spine abnormalities
  • hearing loss or deafness

Furthermore, there is an increased frequency of Duane syndrome in patients with exposure to the drug Thalidomide.

Diagnosis and examinations

An ophthalmologist or orthoptist tests the mobility of the eyes and the eyelid fissure, and the degree of strabismus in different directions of gaze. This happens both when viewing near and far. In addition, the patient follows an object or light with his eyes and is not allowed to move his head. The ophthalmologist also checks whether other eye abnormalities are visible. Hearing loss or deafness also occur in combination with Duane syndrome; an ENT specialist will then follow up on this. Abnormalities of the radius bone in the forearm or vertebral abnormalities in the neck occur sporadically; Taking photos is then necessary to confirm the diagnosis.

Therapy

Usually no treatment is required, but follow-up in children from the age of about six years is recommended. Patients often do not have vision or function problems due to Duane syndrome. For patients who see less well, there are glasses with prism lenses that allow the image to be seen in the corners of the eyes. Occasionally, surgery is performed on the eye muscles to improve eye and head position. However, the results are usually limited because the eye muscle control itself cannot be improved. If there is a risk of a lazy eye due to an abnormal eye position, the good eye is taped off. If necessary, a patient calls on an occupational therapist and/or low vision specialist for handling advice and tips on aids.

Heredity

In 90% of cases, Duane syndrome is not familial. 10% of patients have an affected family member and usually both eyes are affected. Sometimes the cause of the syndrome lies in an error in the hereditary material, but no additional information is yet known about this. To test whether the condition is hereditary, the patient visits a clinical geneticist.

Prognosis

The condition is permanent but not progressive; it will not deteriorate, but neither will it improve. If a patient has no additional symptoms, he or she develops normally and usually has little or no trouble with the condition. He usually deals creatively with the limitations of Duane syndrome.

read more

  • Sixth cranial nerve palsy: Eye movement disorder
  • Eye muscle function test: Examine six eye muscles (Eye examination)
  • Brown syndrome: Eye movement disorder
  • Adie’s Syndrome: Disorder of eyes and reflexes

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