Excerpts of transcript from Science Netlinks

"Why do some people have to wear reading glasses?"

One consequence of aging is a loss of flexibility and elasticity in various tissues. In most cases, the result is just stiffness, a loss of maneuverability or agility. But in the case of the eye, there can be loss of basic function. As the lens gets less able to change shape and focus light, people must resort to wearing glasses for reading. This increase in far-sightedness is almost universal among older people.

We asked Myron Yanoff, chair of the Opthamology Department at MCP Hanneman College in Philadelphia, and he said that losing our near vision is a result of the lens in our eye being unable to focus properly. It often happens because as we age, the lenses become less and less elastic. "As you, I wouldn't say get older, but become more mature, you lose the ability to focus. And that is a very slow and constant thing, almost from birth on, so that by the time you reach the age forty, you do not have the ability to focus at near."  But he says that people who are nearsighted, and already use glasses to see distant objects, may never need any to see their morning paper.  Doctor Yanoff adds that people who get laser surgery to correct their distance vision may also wind up needing reading glasses. Once their eyes are made normal, they too will suffer age-related loss of near vision.

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