REFRACTIVE ERROR / PRESBYOPIA
Refractive error is a problem with focusing light onto the retina due to the shape of the eye. The most common types involve near-sightedness (myopia), far-sightedness (hyperopia), and astigmatism (uneven focus of light). Presbyopia is a condition beginning around age 35, causing progressive difficulty with viewing near objects. This typically results in a need to hold items further and further away in order to read. Refractive error and presbyopia cause blurry vision, headaches, and eye strain, and can be corrected with eyeglasses.