Key Terms

accommodation

ability of the lens to change shape when looking alternatively at a near object and far object

aqueous humor

fluid typically produced in the posterior chamber of the eye, which nourishes the internal structures and maintains a homeostatic eye pressure

astigmatism

when the cornea or lens is curved more steeply in one direction, causing light to focus on multiple points of the retina

canaloplasty

eye surgery that uses a microcatheter to cannulate Schlemm’s canal in order to restore aqueous humor outflow to lower intraocular pressure

cataracts

cloudy areas on the lens of the eye from the breakdown of proteins that affect vision

cones

receptors on the retina for daytime and color vision

conjunctival hyperemia

excess of blood in the eye’s vessels, causing redness

conjunctivitis

infection and inflammation of the conjunctiva, causing redness and irritation; also referred to as “pink eye”

external ocular structures

structures outside the eye responsible for protecting the eye and allowing the eye to rotate and move up and down

glaucoma

group of diseases caused by obstruction or excess production of aqueous humor, resulting in loss of peripheral vision

hyperopia

a condition in which light refracts behind the retina, resulting in close objects appearing blurry and far objects being clearly seen; also known as farsightedness

internal ocular structures

structures inside the eye responsible for light accommodation, eye color, fluid to support eye pressure homeostasis, and the optic nerve

macular degeneration

degeneration of the central portion of the retina, causing gradual loss of central vision

myopia

a condition in which light refracts in front of the retina, resulting in far objects appearing blurry and near objects being clearly seen; also known as nearsightedness

photophobia

abnormal sensitivity to light

presbyopia

a condition that occurs as one ages; the lens thickens and becomes less elastic, which makes it difficult for the eyes to accommodate

refractive errors

when light does not shine directly on the retina, causing distorted vision

rods

receptors on the retina for nighttime vison

trabeculectomy

eye surgery that creates a bypass of obstructed aqueous fluid in the trabecular network to prevent further loss of vision in glaucoma