Nystagmus (Involuntary Eye Movement)

It is an involuntary (uncontrolled) and continuous back-and-forth or jerking movement of the eyes horizontally, vertically, or rotationally around their own axis, preventing them from remaining stationary at the point of fixation.

If it appears during the initial months of infancy, it is congenital (developmental defect of the visual pathways or brain, cataract, albinism). If it manifests in adulthood (acquired), it is typically a sign of stroke, brain tumor, multiple sclerosis, head trauma, or alcohol toxicity.

In nystagmus acquired later in adulthood, because the brain is unaccustomed to this motion, the individual perceives the world (the image) as constantly trembling (oscillopsia) and shaking, leading to vertigo. In congenital nystagmus, thanks to cerebral adaptation, the environment is viewed as stationary, but visual acuity is significantly diminished.

There is a specific angle of gaze where the nystagmus is minimized and the patient sees most clearly. Consequently, patients with nystagmus prefer to hold their heads tilted to the right, left, or downward (abnormal head posture) when watching television or looking at someone.

A clinician's evaluation of the patient's eye movements during pen tracking establishes the diagnosis. However, to discover the underlying etiology, a comprehensive fundoscopic examination, Cranial MRI, and vestibular (inner ear) tests by ENT are performed.

There is no absolute cure; management is planned. First, specialized prismatic glasses or contact lenses are prescribed to address visual deficits. Botox injections into the extraocular muscles can be performed to minimize the shaking. In advanced scenarios, 'Nystagmus Surgery' can reposition the extraocular muscles to align the point of minimal shaking (null point) directly forward, thereby correcting the abnormal head posture.