Nystagmus and Retinal Disease

Nystagmus is a condition where the eyes wobble back and forth, usually horizontally but occasionally vertically in some presentations.  It can occur in conjunction with eye diseases, on its own, or as a result of substance use or abuse.  In fact, nystagmus is one of the signs police officers look for when determining whether or not you’ve been drinking. In otherwise normal eyes, nystagmus can reduce functional vision dramatically.  Imagine looking at the world through a camera that was constantly jittering back and forth, and you have some idea of what this condition can do to how a person operates.  It can cause dizziness, problems with depth perception, and loss of functional acuity.  The muscle movements involved can even warp the structure of the eye, causing astigmatism.

Both Brian and Kender have nystagmus.  Brian’s was diagnosed before I ever met him.  Kender’s was diagnosed when it emerged between 2 and 4 months of age.  This was during the first intense, frenzied period of our family’s diagnosis and treatment of Familial Exudative Vitreo-Retinopathy (FEVR).  After having six children, we had just found out that Brian’s blindness was genetic and affected four of our six children.  Kender was blind, Jarod was blind, the girls were losing vision, and we were out in Detroit in either the operating room or the doctor’s office every couple of days or weeks for months on end.  I was constantly reading and studying, asking questions of the doctors, keeping copies of all the retinal scans and studying them, buying textbooks that had been written by Dr. Trese and his associates and reading them.  When Kender’s eyes began wobbling the same way Brian’s do, a light bulb went off in my head.  I presented my ideas to Dr. Trese, who agreed with my analysis.  To the best of my knowledge, no other eye doctor has made this connection, and I can’t find any evidence of it in the literature when I search.

My suggestion was this: the nystagmus in Brian and Kender is not an independent condition or a problem to be fixed, but rather is a compensating mechanism that actually improves their vision.

Advanced FEVR has left Brian and Kender without a discernible macula or fovea in their usable eyes.  These are the areas of the eye that are used for focal vision.  When you look at a normal retina, you can easily see the macula as a large, dark area near the optic nerve, and the fovea as a smaller, darker area within it.  These areas of the eye contain very high concentrations of light-receptor cells.  They also contain a larger proportion of cone cells, which detect color and detail, as opposed to rod cells, which are better at detecting light/shadow and movement.  Outside of the macula and fovea, there is a lower concentration of both types of light-receptor cells, and the proportion of cone cells is much lower.  These differences account for the differences between your focal vision, or what you see right in front of your eye, and your peripheral vision, or what you see from the side of your eye.

Peripheral vision is highly responsive to movement.  This is why something can more easily “catch your eye” if it is moving.  Brian and Kender are left with only this type of vision.  Nystagmus can provide extra movement, triggering that peripheral perception and actually improving their functional vision.  Nystagmus is also associated with other disorders, such as albinism, that can affect the development of the fovea.  I would argue that nystagmus, when it presents in combination with these other disorders, would again be a compensating behavior rather than a complicating disorder, improving vision rather than reducing it.  It would be fantastic if some ophthalmologist out there could take this on with some studies.

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