Refractive problems of the eye.

Refractive problems of the eye are common. About 25% of adults have detectable myopia, or short-sightedness. Hypermetropia, or long-sightedness, is even more common, with one study estimating about 50% of adults affected. The actual number that have symptomatic refractive problems is far smaller, with about 10% of people needing refractive correction for myopia. The authors give an overview of the common refractive problems of myopia, hypermetropia, presbyopia and astigmatism.