Our cross-country drive last winter from New York to Lake Tahoe was going to be intense, with a pandemic, blizzard, and salad cancellations at McDonald’s. But by Omaha, when the lanes of Interstate 80 seemed to be spinning around in front of my eyes, we entered unexpected territory.
“Are you practicing 80 mph turns?” my wife asked.
Road condition is still normal. Our SUV has new tires. But the lanes often seem blurred together. Sometimes lane separation happens late in the day, sometimes early. Sometimes in the bright sun, sometimes in the fog. If I close one eye, the lanes become separate again.
What happened? I have been wearing myopia glasses since fifth grade; I’ve been seeing my eye doctor for years; My current prescription.
When we got to Tahoe, I went to the optometrist before opening my skateboard. She said my eyes were fine, but advised an MRI to rule out brain bleeding or a tumor. Days later, it did.
She also told me to see a neuro-ophthalmologist, an increasingly rare specialty. Nationally, there are only about 600 of them, and because many do academic research or practice in general ophthalmology, only 250 of them are full-time clinicians. According to an article in the Journal of Ophthalmology-Neuropathy last year, there was no practice in six states.
Tahoe’s optometrist warns it can take months to get an appointment with one of the few practitioners in the area. But my brother, a surgeon at Stanford, helped me get an appointment at Stanford Medical Center, four hours away, in Palo Alto, Ca., the following week. Dr. Heather Moss conducted the 90-minute test, taking measurements that included the extent to which my eyes were properly focused.
My diagnosis: esotropia, i.e., inward rotation of one or both eyes.
When Dr. Moss placed a triangular plastic rod in front of one of the eyes, the bouncing stopped. The piece of plastic is a collection of prisms, varying in strength from top to bottom. She changed the prisms until we got it right.
Eye direction can be outward or upward or downward. All are forms of strabismus, and double vision is the main symptom in adults whose brains are accustomed to perceive two slightly different images. (Without those, you wouldn’t have depth perception or couldn’t see in 3-D.) Some people with symptomatic strabismus get two images. But they’re not okay because the eyes are misaligned and the brain doesn’t compensate for the anatomical-mechanical defect.
Typically congenital, this disease is often diagnosed in children, who have symptoms in the form of “lazy eye”, because the brain blocks images from the weak eye. Some children wear an eye patch over their strong eye to train lazy eye. Many children have surgery to reposition the muscles that control weak eyes.
Strabismus is derived from strabos, the Greek word for “crossed eyes”, aptly describing the response of adults to compensate for the defect by closing one of their eyes. Doing so removes the conflicting binocular images from both eyes, which the brain cannot fix.
According to the journal Ophthamology, about 4% of adults have this condition. But it often goes undiagnosed and people unknowingly live with imperfect eyesight. “Most conventional ophthalmologists only look at the eyes — not eye movements,” says Dr. Marc Dinkin, a neuro-ophthalmologist at Weill Cornell Medicine in New York.
Larry Frohman, a professor at Rutgers New Jersey Medical School and executive vice president of the North American Society of Neurological Ophthalmology, said the specialty field attracts fewer physicians because it requires an extra year of major training. knowledge other than neurology or ophthalmology.
While surgery is sometimes the solution to this misalignment in adults, prisms are the common remedy. They can be permanently sharpened into lenses, shifting light and changing the position of what the eye sees, tricking the brain into interpreting images from both eyes into proper alignment.
Choosing the right level of correction can be difficult. Prisms range in strength from 1 to 40 diopters (1 being the weakest), although they are rarely specified beyond 15 because of the distortion they can produce.
Dr. Moss recommended that I try temporary Fresnel laminated vinyl lenses, which use water to attach to the inside of the lenses. These one-millimeter-thick lenses allow patients to experiment with different intensities. The problem is that they can fall off and the plastic, which contains thin etching lines on the surface, is not as obvious as prisms placed in the ground. I tried 1-diopter lenses and then 2 diopters, before switching to 3-diopters for the next three months.
Driving isn’t difficult anymore, but my vision isn’t perfect anymore, and even seems to be a bit retarded. When I returned to the East Coast, Dr. Dinkin of Weill Cornell took over my care. In his examiner’s chair, I finally experienced double vision.
When a large “A” was displayed on the wall and I removed the Fresnel lens on my glasses, I saw two A’s. When I looked through his hand-held prism, the A magically merged . What I have described as the images bouncing on Interstate 80 are actually separate images that my brain is trying to put together. I didn’t think it was dual vision at the time because the driving lane in the middle looks quite similar to the left lane. In fact, I’ve seen two lanes on the left.
Dr. Dinkin has increased the durability of my prism to 10 diopters. He divided the prisms into lenses for both eyes – 5 and 5 (with light being deflected in different directions). In late spring, Dr. Dinkin said it was time to correct into a pair of permanent lenses.
The new glasses work fine, although another problem has arisen. The lenses have thicker permanent prisms along the edges, so the distortion creates a fun house mirror effect. It is especially problematic when walking down stairs. So I have another pair of glasses, with a slightly weaker prism – 4 and 4 diopters. I’m trying to use them most of the time, saving my 5 and 5 glasses for driving or when I need to increase my vision.
How do I get a diagnosis of strabismus in adulthood? Dr. Dinkin and Dr. Moss agree that I have probably had it most of my life, although the deviation in my left eye is almost imperceptible. No doctor had discovered the problem before because no one had looked for it, and I didn’t raise any complaints. My eyes didn’t move properly. Symptoms of this condition have appeared with age and fatigue.
My decline in vision is just one of the other dangers of getting older. Near the end of my time in Tahoe, I suffered my first serious skiing fall in 20 years, resulting in sprains of my left thumb and right shoulder. No big deal – they get better with ice, rest, splints, and 15 weeks. But along with my eyes, I began to wonder about my long-term disparity. That’s a good thing, I’m not a racehorse.
https://www.nytimes.com/2022/02/26/health/vision-eyesight-neuro-ophthalmology.html A medical mystery laid out by the dim lane