By middle age, the lenses in your eyes harden, becoming less flexible. Your eye muscles increasingly struggle to bend them to focus on this print.
But a new form of training - brain retraining, really - may delay the inevitable age-related loss of close-range visual focus so that you won't need reading glasses. Various studies say it works, though no treatment of any kind works for everybody.
The increasing difficulty of reading small print that begins in middle age is called presbyopia, from the Greek words for “old man” and “eye.” It's exceedingly common, and despite the Greek etymology, women experience it, too. Every five years, the average adult over 30 loses the ability to see another line on the eye reading charts used in eye doctors' offices.
By 45, presbyopia affects an estimated 83 percent of adults in North America. Over age 50, it's nearly universal. It's why my middle-aged friends are getting fitted for bifocals or graduated lenses. There holdouts, of course, who view their cellphones and newspapers at arm's length to make out the words.
The decline in vision is inconvenient, but it's also dangerous, causing falls and auto accidents. Bifocals or graduated lenses can help those with presbyopia read, but they also contribute to falls and accident because they can impair contrast sensitivity (the ability to distinguish between shades of gray) and depth perception.
I'm 45. I don't need to correct my vision for presbyopia yet, but I can tell it's coming. I can still read The New York Times print edition with ease, but to read text in somewhat smaller fronts, I have to strain. Any year now, I figured my eye doctor would tell me it was time to talk about bifocals.
Or so I thought.
Then I undertook a monthslong, strenuous regimen designed to train my brain to correct for what my eye muscles no longer manage.
The approach has been reported in the news media, and perhaps you've heard of it. It's based on perceptual learning, the improvement of visual performance as a result of demanding training on specific images. Some experts have expressed skepticism that it can work, but a number of studies provide evidence that it can improve visual acuity, contrast sensitivity and reading speed.
The training involves looking at images called “Gabor patches” in various conditions. Gabor patches optimally stimulate the part of the brain responsible for vision. A great deal of the training involves trying to see Gabor patches placed between closely spaced, distracting flankers. In training, the flanker spacing is varied, the target contrast is turned way down, and the images are flashed on a screen for fractions of a second - to the point that one can barely see the target.
Do this and similar exercise hundreds of times over multiple sessions weekly；continue for months；and, gradually, presbyopia lessens. a number of studies show.
One study also examined functions of the eye itself and found none of these improvements were because of changes in the eye. They're all in the brain.
Various smartphone apps say they offer this kind of vision-improving training；I used one called GlassesOff, the only one I found that was backed by scientific studies.
