Glossary of Related Terms N-Z ( A-F, G-M )

Nearsightedness: a condition in which distant objects appear blurred

Optic Nerve: The nerve that carries visual impulses from the retina directly to the brain.

Presbyopia: A condition related to the normal aging process, in which it becomes difficult to focus on close-up objects. (learn more)

PRK (Photo-Refractive Keratectomy): A type of laser eye procedure used to treat various refractive or focusing errors of the eye. PRK reshapes tissue on the surface of the cornea, thereby eliminating (or reducing) the corneal refractive error and significantly changing the requirement for corrective eyewear. The procedure, although less surgically invasive, generally requires a longer healing process. .

Refraction: The eyes' natural ability to focus light rays properly on the retina.

Retina: The nerve fiber layer or inner surface of the eyeball on which images are projected and delivered to the optic nerve as impulses for transmission directly to the brain.

Spots: See Floaters.

Strabismus: A condition in which difficulty with eye muscle balance and coordination causes one or both eyes to turn in, out, up, or down. (learn more)

Tonometry: A test that measures the internal fluid pressure within the eye. Increased fluid pressure is an indicator in the diagnosis of glaucoma.

Visual Acuity: A test of the eyes' ability to see sharply and clearly at all distances; part of a comprehensive eye exam that may be tested with or without a vision correction.

<<back to Vision Health and Wellness