Corneal topography Health Dictionary

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Corneal Topography: From 1 Different Sources

(videokeratography) an imaging technique used to study the shape and refractive power of the cornea in detail. An image projected onto the cornea is analysed by a computer to produce a representation of the shape and refractive power of the corneal surface. Corneal topography has an important role in the management of corneal disease and refractive surgery.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Corneal Graft

Also known as keratoplasty. If the cornea (see EYE) becomes damaged or diseased and vision is impaired, it can be removed and replaced by a corneal graft. The graft is taken from the cornea of a human donor. Some of the indications for corneal grafting include keratoconus (conicalshaped cornea), corneal dystrophies, severe corneal scarring following HERPES SIMPLEX, and alkali burns or other injury. Because the graft is a foreign protein, there is a danger that the recipient’s immune system may set up a reaction causing rejection of the graft. Rejection results in OEDEMA of the graft with subsequent poor vision. Once a corneal graft has been taken from a donor, it should be used as quickly as possible. Corneas can be stored for days in tissue-culture medium at low temperature. A small number of grafts are autografts in which a patient’s cornea is repositioned.

The Department of Health has drawn up a list of suitable eye-banks to which people can apply to bequeath their eyes, and an o?cial form is now available for the bequest of eyes. (See also DONORS; TRANSPLANTATION.)... corneal graft

Corneal Ulcer

See: EYES, INFECTION. ... corneal ulcer

Corneal Reflex

Instinctive closing of the eyelids when the surface of the cornea (see EYE) is lightly touched with a ?ne hair.... corneal reflex

Corneal Abrasion

A scratch or defect in the epithelium (outer layer) of the cornea caused by a small, sharp particle in the eye (see eye, foreign body in) or by an injury. Corneal abrasions usually heal quickly but may cause severe pain and photophobia. Treatment includes covering the eye with a patch, analgesic drugs to relieve pain, and, if the eye muscles go into spasm, eyedrops containing cycloplegic drugs (which paralyse the ciliary muscle, preventing accommodation). Antibiotic eyedrops are usually

given to prevent bacterial infection, which can lead to a corneal ulcer.... corneal abrasion

Corneal Transplant

See corneal graft.... corneal transplant

Corneal Arcus

a white or greyish line in the periphery of the cornea, concentric with but separated from the edge by a clear zone. It begins above and below but may become a continuous ring. It consists of an infiltration of fatty material and is common in the elderly (arcus senilis). When it occurs in younger people (arcus juvenilis) it may indicate *hyperlipidaemia. It does not affect vision.... corneal arcus

Corneal Reflex

reflex blinking of both eyes normally elicited by lightly touching the cornea of one eye. This reflex is lost in deep coma, during general anaesthesia, and in death; it is therefore one of the tests used to confirm brainstem death.... corneal reflex

Corneal Ring

a ring designed to be inserted into the peripheral tissue of the cornea in order to alter the curvature of the corneal surface. It is undergoing trials to assess its ability to correct errors of refraction. In myopia (short-sightedness), for example, the ring would be required to stretch the corneal tissue peripherally and thus flatten the central corneal curvature in order to correct the myopia.... corneal ring

Topography

n. the study of the different regions of the body, including the description of its parts in relation to the surrounding structures. —topographical adj.... topography

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