Age Related Macular Degeneration (ARMD)
the breaking down of the macula, the back portion of the retina that is responsible for clear vision. There are two main types of ARMD. (1) Involutional ARMD (Dry ARMD) results in a slow, progressive loss of central vision (usually not beyond 20/200), for which there is currently no treatment. (2) Exudative (Wet ARMD) results in distorted or blurred vision caused by the growth of the neovascular membrane in or near the macula. This maybe treated, if diagnosed early, without significant loss of central vision. (Ref: WebMD)
Amblyopia
a condition in which there is loss of vision for no apparent reason; the eye appears healthy, but vision is poor. This is commonly referred to as "lazy eye". The decreased vision is not correctable with optical devices. Patients with severe nutritional deprivation or vitamin B12 deficiency may experience simulated amblyopia. Complete recovery is possible with good diet and B vitamins, however, prolonged deficiency results in permanent loss of central vision. (Ref: WebMD)
Anisometropia
inequality of considerable degree in the refractive power of the two eyes. For example, one eye is nearsighted and the other is farsighted.
Anterior uveitis
aninflammation of the middle layer of the eye, which includes the iris (colored part of the eye) and adjacent tissue, known as the ciliary body. If untreated, it can cause permanent damage and loss of vision from the development of glaucoma, cataract, or retinal edema. Anterior uveitis can occur as a result of trauma to the eye, such as a blow or foreign body penetrating the eye. It can also be a complication of another eye disease, or it may be associated with general health problems such as rheumatoid arthritis, rubella, or mumps. In most cases, there is no obvious underlying cause. Signs/symptoms may include a red, sore, and inflamed eye; blurring of vision; sensitivity to light; and/or a small pupil. (Ref: AOA)
Aphakic Lens
a contact lens designed to meet the needs of patients that have had their crystalline lens removed due to the development of cataracts.
Aspheric Lens
a not-quite-spherical contact lens that can improve contrast sensitivity and depth perception for borderline astigmats or emerging presbyopes. The power changes gradually—from the center to the edge of the lens.
Astigmatism
a condition caused by an irregularly shaped cornea (shaped more like a football than a baseball), resulting in two focal points, causing light images to focus on two separate points in the eye, which results in a blurred or distorted image. Astigmatism can be corrected with toric contact lenses.
