Glossary
What those fancy words really mean...
Accommodation--This is the ability of the eye to focus clearly on any object.
Amaurotic Eye--A blind eye
Amblyopia--lowered visual acuity. Also called a "lazy eye". An amblyopic eye cannot see 20/20 and there is no medical reason for the lower acuity.
Aniridia--Absence of an iris.
Anisocoria--When the pupils are not the same size between the two eyes. Twenty percent of the population are born with anisocoria.
Asthenopia--Also called eyestrain. A feeling of fatigue, discomfort, or pain around the eyes after using the eyes for a longer period of time.
Astigmatism--An eye with astigmatism is not perfectly round, it is instead shaped more like a football. Because it is more curved like a football, people with astgmatism have a hard time focusing on objects at both distance and near because light is coming into the eye at different angles.
Blepharitis--An inflammatory condition affecting the eyelid margins around the eyelashes. Can cause dry eye syndrome.
Cataract--An opacity in the crystalline lens of the eye that blocks vision.
Ciliary body--A structure inside the eye that creates the fluid in the front of the eyeball (aqueous humor). This fluid creates the eye's own fluid pressure that changes throughout the day. This pressure is what we measure to assess risk for glaucoma. The ciliary body also has a ciliary muscle that helps our eyes focus from far to near by pulling on the lens and changing its shape
Conjunctivitis--An inflammation of the tissues around the iris (the whites of the eyes).
Cornea--The clear portion of the eye that is the first surface light passes through on the way to the retina. The cornea is located over top of the iris.
Crystalline Lens--The part of the eye behind the iris that helps us focus by changing shape with the help of the ciliary body. With age, this lens hardens and will no longer change shape (presbyopia), and eventually will start to yellow and haze forming a cataract.
Diopter--The unit we use to determine your prescription. It is designated in quarter intervals.
Diplopia--Double vision.
Ectropion--When the lower eyelid turns outward and the tears of the eye overflow and run down the cheek. This usually occurs in an older individual.
Emmetropia--The normal refractive state of the eye, no prescription at all. This eye is not far-sighted, nor near-sighted.
Entropion--When the lower eyelid turns inward and the lower eyelashes start to rub against the cornea. This usually occurs in an older individual.
Eyestrain--See asthenopia.
Glaucoma--An ocular disease characterized by the elevation of the fluid pressure inside the eye. This causes damage to the opic nerve fibers entering the optic nerve and results in peripheral vision loss.
Hordeolum--Also called a stye. This is an infection of an eyelash follicle.
Hyperopia--far-sighted. The eye would rather see things far away then try and focus on near objects.
Intraocular pressure--The ciliary body inside the eye makes a fluid called aqueous humor. This fluid keeps the front of the eye round and healthy. The fluid pressure inside the eye, caused by the creation and drainage of this fluid, is what is monitored for risk for glaucoma.
Keratoconus--A corneal degeneration beginning during teenage years and progressing slowly throughout life. The front lower portion of the cornea starts to thin and push forward creating a cone shape.
Myopia--near-sighted. The eye cannot see objects far away, only up close.
Nystagmus--A repetitive, rhythmic, involuntary movement of the eyes.
Pinguecula--A benign, elevated, yellowish-white mass of tissue located on the white part of the eye near the iris. This is much like a callous on the eye. It is not dangerous, and does not need treatment.
Presbyopia--This usually occurs around the age of 40. The crystalline lens inside the eye hardens up and will not change shape to focus up close anymore. Usually a person can wear magnification, like bifocals, to help with this sometimes sudden and frustrating loss of focusing ability.
Pterygium--A fold of white tissue that extends from the white part of the eye onto the cornea. This is usually seen in individuals who spend a lot of time outside in sunny, windy, and dusty places. This growth is also benign, but if it grows into the pupil area and compromises vision it can be removed with surgery.
Stereopsis--the ability to see depth; depth perception.
Uveitis--An inflammation of the iris and/or ciliary body.
Visual acuity--The ability to see two seperate objects as separate. The normal eye can resolve two objects as seperate if they are seperated by an angular distance of one minute of arc at 20 feet (20/20).