Glossary
Accommodation: The ability of the eye's natural lens to change shape to focus on objects at various distances.
Anesthesia: Medication that eliminates or reduces pain for surgical procedures. Local or regional anesthesia numbs only a certain area.
Apodization: The gradual reduction or blending of varying diffractive step heights. The application of apodization to intraocular lenses is a patented process by Alcon and can only be found in the AcrySof® IQ ReSTOR® IOL.
Aspheric optic: A type of lens designed to compensate for spherical aberration, resulting in improved image quality.
Astigmatism: A vision problem that results in blurred distance and/or near vision. Light rays entering the eye are bent unequally, preventing the formation of a sharp focal point on the retina.
Cataract: A "clouding" of the lens in your eye. As light passes through the cataractous lens, it is diffused or scattered, resulting in blurred or defocused vision.
Contrast sensitivity: The ability of the eye to differentiate between an object and its background.
Cornea: The clear protective surface of the eye.
Crystalline lens: The transparent disc behind the pupil that helps bring light rays to a focus on the retina.
Diffraction: The spreading of light that occurs when light passes through discontinuities (i.e., the steps or edges of a lens). In an optical system, light can be diffracted to form multiple focal points or images.
Distance vision: The range of vision that includes focal points 7 feet or further from your eyes. Items that typically fall within this range include billboards, street signs and movie screens.
Halos: A circular flare or hazy ring that may appear around a headlight or other light source.
Intermediate vision: The range of vision that includes focal points between 16 inches and 7 feet away from your eyes. Items that typically fall within this range include computer screens and car dashboards.
Intraocular lens (IOL): An artificial lens that is implanted in the eye during cataract surgery to replace the eye's clouded crystalline lens.
Lens haptics: Two arms on the IOL that help keep the lens in place and centered in the eye.
Lens optic: The round central portion of the IOL that serves as the corrective lens.
Monofocal IOL: An intraocular lens that provides patients with only one focal point. Typically, these lenses only correct distance vision.
Multifocal IOL: An intraocular lens that provides patients with multiple focal points, correcting vision at a range of distances.
Near vision: The range of vision that includes focal points 16 inches or closer to your eyes. Items that typically fall within this range include books, newspapers and medicine bottles. Also known as "reading vision."
Phacoemulsification: Also called "phaco," this cataract surgery procedure involves using a device with a vibrating, ultrasonic tip to gently break up cataracts and remove them from the eye.
Presbyopia: An age-related condition in which the eye loses its ability to focus properly, resulting in blurred close-range vision. The individual is no longer able to read clearly and typically requires reading glasses or corrective contact lenses.
Refraction: Redirection of light rays as they pass through a lens.
Retina: The transmitter located at the back of your eye that sends the images to your brain.
Spherical aberration: An irregularity in the shape of the lens. As the eye ages, the lens gets thicker and rounder, causing image quality to deteriorate. Often associated with loss of contrast sensitivity and poor night vision.
Glossary Terms
Roll over the bold purple text to view the definition. A full listing of terms is available in the glossary.