Click on any of the words in this list. The definition will appear in the area to the right.
Aqueous humor:
A clear, watery fluid that circulates through the eye, providing vital nourishment. It also provides the pressure necessary to maintain the shape of the eye. When the aqueous humor is unable to drain, eye pressure increases, which can lead to glaucoma.

Cornea:
A clear part of the eye that covers the iris and pupil.

Eye pressure:
The pressure inside the eyeball that keeps it firm and round. It comes from the aqueous humor and vitreous body contained in the eye. Eye pressure is also called intraocular pressure (IOP).
Dilated eye exam:
Using drops to widen the pupil, your doctor uses a special magnifying lens to examine your retina and your optic nerve.
Glaucoma:
A group of diseases that can damage the eye's optic nerve and result in vision loss and blindness.
Hyperemia:
Increased redness in the eye.
IOP:
Acronym for intraocular pressure, or the inner pressure of the eye.
Intraocular pressure:
Also known as IOP, it is the pressure that helps maintain the shape of the eye.
mm Hg:
An abbreviation for millimeters of mercury, which is how IOP is measured.
Optic nerve:
The nerve in the back of the eye that carries visual information from the eye to the brain.
Peripheral vision:
Side vision. Typically the first areas affected by glaucoma.
Primary open-angle glaucoma:
The most common form of glaucoma, it can lead to loss of vision or blindness. It is called “primary” because it is a condition unto itself and not the result of any other disease.
Prostaglandin analogues:
Glaucoma medications that increase the drainage of aqueous fluids in the eye, bypassing the eye's trabecular meshwork drainage system.
Retina:
The sensory membrane at the back of the eye that receives the image formed by the lens and sends it to the brain via the optic nerve.
Risk factor:
Something that increases your susceptibility. Risk factors for glaucoma may include high intraocular pressure, a family history of glaucoma, diabetes, and African-American or Hispanic ethnicity.
Tonometry:
A test for glaucoma that is used to determine the pressure inside the eye (IOP).
Trabecular meshwork:
The mesh-like drainage canals in the eye.

Visual acuity:
An eye chart test that measures vision at various distances.
Visual field:
The entire expanse of space visible at a given instant without moving the eyes. Also called field of vision.