The Human Eye - Structure and Defects

Core concept

Common eye defects include myopia (short-sightedness), where distant objects appear blurry because the image forms in front of the retina, corrected using a concave lens; and hypermetropia (long-sightedness), where nearby objects appear blurry because the image forms behind the retina, corrected using a convex lens. Presbyopia, an age-related condition, occurs when the eye's lens loses flexibility, reducing accommodation ability, often requiring bifocal lenses to correct both near and distant vision.