I'm 39. I've noticed when I drive that I have more trouble focusing at night, and I seem particularly sensitive to glare from headlights, streetlights and signs. I never used to be bothered by this. I don't notice a problem in any other context. Is this just a matter of age, or is this the first sign of some serious problem?

Dana

Most of the vision difficulties associated with driving at night relate to the fact that the eye's pupil enlarges in darkness, allowing more light to pass into the eye. This generally is not a problem, unless there are abnormalities in the eye that distort the light rays.

The two most common causes of light distortion are cataracts and slight undercorrection of nearsightedness (myopia) or astigmatism. Cataracts, in which the eye's lens gradually becomes opaque, usually do not develop until people are in their 50s or 60s. Severe astigmatism, which is related to the irregular curvature of the cornea, can also cause nighttime glare. Less common causes of light distortion include opacities of the cornea, such as those that may occur after an eye infection or trauma to the eye.

The eye usually retains excellent focusing ability until age 40, at which time presbyopia sets in. Presbyopia is a condition in which a person has difficulty focusing on near objects, such as the print in a newspaper article. However, presbyopia should not affect your driving vision because you do not "focus" your eyes when looking at distant objects.

I recommend that you see an ophthalmologist for a complete eye exam to determine if there are any abnormalities with your eyes.