Cataract — A clouding of the lens of the eye. The normally clear aspirin-sized lens of the eye starts to become cloudy, which will eventually impair normal vision.
Cornea — The clear front window of the eye that transmits and focuses light into the eye.
Crystalline lens — A transparent, colorless body located in the front third of the eyeball, behind the iris, that helps bring rays of light to a focus on the retina.
Fovea — The central point on the retina that produces the sharpest vision.
Functional vision — The ability to see clearly while performing daily activities in varying levels of light.
Halo — Hazy ring around bright lights seen by some patients with refractive error or optical defects (e.g., cataracts or corneal swelling). This symptom may occur after surgery.
Intraocular lens — A small synthetic lens, made of a hard plastic (polymethylmethacrylate or PMMA), silicone, acrylic, or hydrogel material implanted into an eye after cataract surgery to replace crystalline lens, which has been removed.
Iris — Circular, colored portion of the eye. Its opening forms the pupil. The iris helps regulate the amount of light that enters the eye.
Monofocal IOL — An implantable intraocular lens that provides good distance and sometimes intermediate vision but doesn't correct near vision. Usually requires corrective lenses or eyeglasses after surgery for reading and near vision tasks.
Multifocal IOL — An implantable intraocular lens that is designed to provide distance and near vision simultaneously. Some multifocal IOLs also provide intermediate vision. Increased glare and halos reported at night.
Ophthalmologist — A medical doctor (MD) specializing in refractive, medical, and surgical treatment of eye diseases and disorders.
Posterior chamber — The fluid-filled space between the back of the iris and the capsular bag.
Presbyopia — A condition in which the natural crystalline lens of the eye loses its ability to “accommodate”, meaning its ability to switch from seeing objects at a distance (one focal point) to seeing near objects (second focal point).
Pupil — The opening at the center of the iris of the eye that varies in diameter depending upon the brightness of the light coming into the eye.
Retina — The thin membranous lining of the rear two thirds of the eye that converts images from the eye’s optical system into electrical impulses sent along the optic nerve for transmission to the brain.
Visual acuity — The clarity or clearness of the vision, a measure of how well a person sees. The ability to distinguish details and shapes of objects; also called central vision.
