eye disorders
Overview of Refractive Disorders
Introduction
In refractive disorders, light rays entering the eye are not focused on the retina, causing blurred vision. The shape of the eye or cornea or age-related stiffness of the lens may decrease the focusing power of the eye. Objects may appear blurry when far away, near, or both. An ophthalmologist or optometrist determines how best to correct vision. Eyeglasses, contact lenses, or refractive surgery can correct vision. Normally, the cornea and lens bend (refract) incoming light rays to focus them on the retina. When there is a refractive error, the cornea and lens cannot focus light rays on the retina. Refractive errors can be corrected by eyeglasses, contact lenses, or eye surgery. The eye normally creates a clear image because the cornea and lens bend (refract) incoming light rays to focus them on the retina. The shape of the cornea is fixed, but the lens changes shape to focus on objects at various distances from the eye. By becoming more rounded, the lens allows near objects to be focused. By becoming flatter, the lens allows objects farther away to be focused. When the cornea and lens cannot focus the image of an object sharply on the retina, it is called a refractive error. The lens of the eye is flexible and changes its shape to focus on objects at various distances but begins to lose this flexibility after about age 43. 