Causes of nystagmus

Nystagmus is usually idiopathic, which means that causes that cause it are not known. Some damage is speculated to the cerebral strain and is rather functional and not organic, which means nothing is shown in imaging tests, such as CT or MRI.

It is usually not inherited unless it coexists with other ocular diseases that are inherited.

Ophthalmic diseases

The main concern of ophthalmologists is to exclude all those serious diseases, which may include to their symptomatology nystagmus.

Diseases such as the amaurosis Leber, various other inherited retinal diseases, ocular tumors, retinopathy of prematurity, etc. cause nystagmus and unfortunately are difficult to identify when the child is very young.

 
Color blindness is a disease that concerns the sensitive color photoreceptors (cones) and is very similar to the relative idiopathic nystagmus. The differential diagnosis is particularly difficult in young ages, in which color perception cannot be examined.

Photophobia and "paradoxical reaction of the pupil ', ie the pupil’s contraction (at least initially, instead of the expected dilatation) when we turn down the lights, can help, but it takes a special test, called electroretinogram (ΗΑΓ) to have a diagnosis. This test consists a measuring of the weak electric current produced by the retina when it is stimulated by specific light stimulation.

Since this test uses special electrodes that touch the child’s eye and can make it feel uncomfortable, most ophthalmologists avoid it, unless a hereditary disease is suspected. After all, colorblindness is not treatable.

 

Systemic diseases

The most common systemic disease that causes nystagmus is Albinism. This is a rare hereditary disease, which appears with partial or total lack of melanin pigment in the eyes, skin and hair. In severe cases the diagnosis is obvious from the pale skin and white hair, but the mild types are not always that easy to recognize. All patients with albinism also have nystagmus, possibly due to a disturbance in the macula (the central region of the retina). The disease must always be sought in the ophthalmological examination of children with nystagmus, because sometimes Albinism is associated with other rare syndromes that predispose to serious infections and malignancies.

 

Disorders of the central nervous system
In a small percentage, nystagmus is caused by some recognizable brain damage. Children with cerebral palsy or other disorders of the central nervous system exhibit nystagmus more frequently than the general population.

If nystagmus is not present at birth but appears after the age of 6 months old, a detailed laboratory testing should be done to exclude brain tumors or other neurological problems. The same thing must be done if nystagmus shows any kind of unusual features, such as if it is episodic or if it concerns only one eye or both, but they move in opposite directions. Accompanying symptoms such as headaches, seizures, changes in personality or developmental delay may also mean the existence of a more serious neurological problem that is causing nystagmus.