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Prime Time: There are cataracts, and then there are cataracts

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Prime Time: There are cataracts, and then there are cataracts
Bemidji Minnesota P.O. Box 455 56619

Gooseberry Falls, Victoria Falls and Niagara Falls are cataracts. So is Vernal Falls in Yosemite, where three hikers died recently. The Nile, however, has six major cataracts plus some lesser ones that are not waterfalls, just whitewater places where the river has encountered hard-to-erode rock strata. But there is a third kind of cataract, a medical kind.

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I had only two cataracts: eye lenses that had gradually gotten cruddy enough that glasses could not correct my vision to 20/20 and that street lights, neon signs and headlights halated badly, making night driving both tiring and dangerous. Those cruddy lenses were quite normal.

How can such a pathologic condition be "normal?" Normal is a difficult word in biology, psychology, medicine and elsewhere. Biologically, my cataracts were normal because I am old, but my vision otherwise was not normal. If you can read the 20/20 line near the bottom of the chart from 20 feet away, your eyes are "normal." If you can read down to only two lines above it, you are 20/40, slightly below normal (and still allowed to drive without glasses). I've not been 20/20 since I was a pre-teen, and by adulthood, I could not read the big E at the top of the chart, which is 20/400.

Thus, I was severely myopic (near-sighted). So was Elaine. Other genes modify the details, but there is a recessive gene that causes our kind of myopia, and we each had two copies of it. All three kids are likewise myopic. Neither of my parents was myopic, so each carried a dominant gene for normal vision, as well as the recessive gene for myopia, which each passed on to me.

But both my folks wore glasses, because they were normal. Humans and most mammals focus on nearby objects by using eye muscles that change the shape of their eye lenses to bend incoming light appropriately. A lens normally hardens with age, to the point where those muscles cannot focus it close up. Thus, age-related farsightedness is normal. That's why so many older people can do a lot without glasses, but must don specs to read.

Lenses also normally crud up with age and become more yellow. When Dr. Larry Womack, one of my former students, examined me three decades ago, he said, "By the way, you have cataracts."

He could tell the lenses were crudding up long before I could. But, in the last decade, the nighttime halation became intolerable, and my ophthalmologic surgeon, "Dr. O." agreed to replace my cataracts with plastic. I say "agreed to" because he was reluctant.

Several years ago, I discovered a peculiar distortion in a small spot in my right visual field, and Dr. O. feared that the surgical procedure might disturb that. A retinal specialist from Sanford Fargo has monitored it over the years, and decided it was a stable abnormality, so the surgery would likely be safe. It seems to have been.

Cataract surgery is an interesting procedure, which many of you have gone through. No fun, but not painful, and you're awake the whole time.

No problem after the left eye surgery; just had the optical shop knock the left lens out of my trifocals and used my right eye as before. I could see well enough with my new left lens and right trifocal lens to drive, and could read with my right eye. But after the right cataract was replaced, I had to buy dime store specs to read. I could drive without glasses, though my new eyes are only 20/40 or so. After both eyes had settled down, I had a new exam and got new trifocals, and my vision is sharper than it has been for decades.

But now I'm a normal old person, visually. My artificial lenses are rigid, but relatively far-sighted. My trifocals are not thick. And my habits of the last 60 years are useless. Basically, my extremely myopic eyes were low-power microscopes, sharply focused a few inches from my face. If I wanted to trim a hangnail or read fine print on a label, I'd take my glasses off. I still automatically start to do that, but what I need is a magnifying glass. Actually, I'm keeping a powerful pair of dime store readers for extremely close work.

One observation that Dr. O. has made several times is, "Everyone over 50 has cataracts."

So you youngsters have something to look forward to. It's normal.

--

Evan Hazard, a retired Bemidji State University biology professor, also writes "Northland Stargazing" the fourth Friday of each month.

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