I noticed recently I can’t see clearly up close. Why is that?

Some people can go along with good distance vision (with or without glasses) most of their life until they get close to 40, and then they notice they can’t see up close as well as before. A common complaint is that after reading for a while, when they look up, things in the distance are momentarily blurry.

This is a first sign that the lens is not changing focus as quickly as it used to/should. This can happen in some people a little before 40 and in others a little after 40 and is due to a condition called presbyopia. Farsighted people have problems with near vision before nearsighted ones. Interestingly enough, patients with long arms will be bothered by presbyopia later than patients with shorter arms.

In our eye, we have a lens which changes shape to give it more power to allow us to do close work like reading or sewing, and then changes back to its normal shape to let us see things in the distance. It does this any time you look at things at different distances. The term for this is accommodation. Children have lots of accommodative power, but this ability starts to decrease around 40 years of age and is almost completely gone by age 60. Children have the ablility to focus around 20 diopters (the measure of accommodation), which means they can focus on objects as close as 5 cm from them, but this decreases to 1 diopter by age 60. Presbyopia is a vision condition in which this lens loses its elasticity, so it doesn’t change shape easily, which then makes it difficult for you to focus on close objects. Presbyopia is a natural part of the aging process of the eye. It is not a disease and it cannot be prevented. You can’t eat special foods, or take vitamins or do exercises to prevent it. People whose occupations require a lot of near focusing will go to the optometrist earlier for presbyopic corrections than those whose occupations do not. For example, a lawyer will notice problems with near vision earlier than a farmer. This partially explains why some people will get bifocals earlier than others.

Will the glasses just be for reading?

No. The first thing people tend to notice is that they have to hold reading materials at arm’s length because of blurred vision at normal reading distance, and eye fatigue along with headaches when doing close work. But it is the ability to focus up close that is going so it is not just reading; seeing anything up close is difficult, like threading a needle, seeing the hands on your watch, seeing bones in fish, etc.

A comprehensive optometric examination will include testing for presbyopia.

You can be nearsighted or farsighted and then develop presbyopia, so your optometrist will determine the specific lenses to allow you to see clearly and comfortably at all distances . They can prescribe reading glasses, bifocals, trifocals, or progressive lenses.