Eye & Vision Glossary

 This glossary provides some basic definitions for a variety of eye and
vision-related terms. If you know of a term you would like to see added to
the list, please contact us.

Aqueous Humor: the thin layer of clear fluid between the cornea and the iris.
 
Cornea: the transparent, domed outer covering of the eyeball that covers the pupil and the iris.

Fovea: a pinpoint-sized indentation at the center of the macula responsible for our sharpest vision.
 
Iris: the round, colored portion of the eye. Suspended between the cornea and the lens in the aqueous humor, it regulates, in part, how much light enters the eye.
 
Lens: the clear structure inside the eye between the iris and the vitreous humor. The lens focuses light entering through the pupil to form an image on the retina.

Macula: small, central area of the retina with a concentration of light-sensitive cells, providing fine visual detail for activities like reading and driving.

Ophthalmologists (MDs): are trained eye surgeons and physicians specializing in medical and surgical treatment of vision disorders and diseases, like Dr. Lebowitz.

Opticians: See Registered Dispensing Opticians (RDOs)

Optometrists (ODs): are primary healthcare practitioners qualified to diagnose and treat vision disorders and certain diseases of the eye, like SJEA partners Dr. Cole and Dr. Feinstein. An optometrist prescribes eyewear, contact lens and some medications.
 
 Optic Nerve: the bundle of nerve fibers connecting the retina at the back of the eye to the brain. The optic nerve translates light that strikes the retina into nerve impulses that the brain interprets.
 
Pupil: the dark center of the iris through which light passes into the eye.

Registered Dispensing Opticians (RDOs): , are trained and accredited to fill prescriptions issued by our optometrists for corrective eyewear, like the ones working in our optical department. Opticians, unlike optometrists and ophthalmologists, do not perform comprehensive eye exams.
 
Retina: the light-sensitive membrane of nerves on the back of the eye. The retina translates light into nerve impulses which are sent to the brain via the optic nerve.
 
Vitreous Humor: the clear, watery fluid inside the eyeball filling the space between the lens and the retina.