Originally published in The New York Times on 5/1/18, by Lisa Sanders, M.d.
The young woman rubbed her eyes. The numbers and letters on her computer screen jumped erratically. So did the world around her. This had happened before, but late at night when she was tired, never in the middle of the day. The light from the screen suddenly seemed too bright. And her headache, the one that was always present these days, tightened from a dull ache to a squeezing pressure on the back of her head and neck. Nearly in tears from pain and frustration, the 19-year-old called her mother. She couldn’t see; she couldn’t drive. Could her mother pick her up from work?
The problems with her eyes began in grade school. Two years earlier, she nearly went blind. All she could see on the left was a rim of light. Everything else was blocked by a big black spot. And then a black dot appeared in her right eye as well. Her parents took her to see many eye doctors, only to be told that there was nothing wrong. One doctor told them that she had “emotional blindness.” The young woman’s vision somehow got a lot better on its own, and though the black dot still obstructed some of her vision, for the last eight months she’d been able to drive — so important in this small mountain town an hour north of San Diego.
Problems in the Brain?
Now she couldn’t see for what seemed like a different reason. The young woman’s mother arranged for her to go to San Diego to see a neuro-ophthalmologist — a doctor who specializes in vision problems that originate in the brain. When they got to the office, though, the young woman’s vision and headache had returned to their imperfect but baseline state. She told the doctor that her symptoms were least intrusive in the morning; standing and walking seemed to make everything worse. Come back later, the doctor instructed. Mother and daughter walked around and shopped. When a couple of hours later the daughter’s eyes started jumping and her headache worsened, they hurried back to the office.
The doctor took one look at the young woman’s eyes and told her she had nystagmus. It’s a failure in the parts of the brain that allow our eyes to stay focused when the object being observed or the observer moves. Problems in the inner ear — where head position is perceived — are the most common cause of nystagmus, usually accompanied by vertigo. Persistent nystagmus is worrisome because it can indicate abnormalities in other parts of the brain, primarily the cerebellum — the chief coordinator of all movement. The doctor sent the patient to the Sharp Memorial Hospital emergency room for an M.R.I.; it would reveal if a clot or mass in the brain was causing the nystagmus.
There was no clot, no mass, but there was an abnormality. At the lowest part of the young woman’s brain, where the spinal cord emerges, a tiny sliver of cerebellum was visible just below the skull. A little slippage of brain tissue into the spinal column can be normal as long as it is no more than five millimeters below the skull; anything more is considered pathological. Hers was right at five millimeters.