Nystagmus surgery cannot correct this vision disorder but might allow for more comfortable position of the head when a patient focuses. Horizontal rectus tenotomy repositions the muscles in the eye to reduce the amount of head movement needed for a fixed gaze. An incision is made in the conjunctiva, which is the white membrane of the eye, and the rectus muscle is pulled away from its outer layer. The surgeon then reattaches the muscle to a different point in the membrane.
This disorder affects vision in several ways, causing slight vision defects or total blindness. Nystagmus causes involuntary horizontal, vertical, or circular movement of the eye. It indicates a problem in how the brain perceives images and sends signals to the eye to regulate sight. In patients diagnosed with nystagmus, the eye and the brain fail to work in tandem.
When light passes through the eye onto the retina, it automatically enters pathways to the brain. Specific areas in the brain receive messages and send signals back to the eye to control movement and allow sharp focus. If these functions misfire, a patient cannot control eye movement needed to fix attention on an object.
Many patients learn to hold the head in a certain position to lessen the intensity of nystagmus. This is called the null point, an angle when eye movement slows down enough to improve gaze. Some patients find nodding the head helps, but for others the head must be held in an uncomfortable position before vision become clearer.
Nystagmus surgery identifies the null point in individual patients and makes adjustments to horizontal eye muscles. It allows the patient a wider range of head position to see nearby or faraway objects. Nystagmus surgery might be helpful to broaden the gaze zone and discover where vision appears best.
Two types of nystagmus exist. Early onset nystagmus affects infants. This disorder might occur in babies born with glaucoma, cataracts, or other problems of the retina. In some cases, visual stimulation as the infant ages might limit the amount of vision loss. Removal of cataracts might also increase the amount of light reaching the retina to permit messages to the brain.
Acquired nystagmus develops in adults after a stroke or other medical condition. Brain tumors or head injuries might disrupt the signaling process between the brain and eyes. Some medication is also linked to adult nystagmus, along with diseases that harm the part of the brain controlling eye movement. Nystagmus surgery might be helpful in some adults to permit more comfortable head positions for better vision.