Bma Illustrated Medical Dictionary

keratoconjunctivitisInflammation of

thecorneaassociated with conjunctivitis.

The most common form, epidemic kera-

toconjunctivitis, is caused by a virus and

is highly infectious. The conjunctivitis is

often severe and may destroy the surface

of the conjunctiva. Tiny opaque spots

develop in the cornea that may interfere

with vision and persist for months. There

is no specific treatment, but corneal

spots may be minimized by using eye-

drops containing corticosteroid drugs.

keratoconjunctivitis siccaPersistent

dryness of the corneaand conjunctiva

caused by deficiency in tear production.

The condition is associated with auto-

immune disorderssuch as rheumatoid

arthritis,Sjögren’s syndrome, and sys-

temic lupus erythematosus.Prolonged

dryness may lead to blurred vision, itch-

ing, grittiness, and, in severe cases, the

formation of a corneal ulcer. The most

effective treatment is frequent use of

artificial tears (see tears, artificial).

keratoconusAn inherited disorder of

the eye in which the corneabecomes

gradually thinned and conical. The con-

dition affects both eyes and usually

develops around puberty, giving rise to

increasing myopiaand progressive dis-

tortion of vision that cannot be fully

corrected by glasses. Hard contact len-

ses improve vision in the early stages,

but when vision has seriously deterio-

rated and contact lenses are no longer

helpful it generally becomes necessary

to perform a corneal graft.

keratolytic drugsDrugs that loosen

and remove the tough outer layer of

skin. Keratolytic drugs, which include urea

and salicylic acidpreparations, are used to

treat skin and scalp disorders, such as

warts,acne,dandruff, and psoriasis.

keratomalacia A progressive disease of

the eye, caused by severe vitamin A de-

ficiency, in which the corneabecomes

opaque and ulcerated. Perforation of

the cornea is common, often leading to

loss of the eye through infection. The

condition usually occurs only in sev-

erely malnourished children and is a

common cause of blindness in develop-

ing countries. In the early stages, the

damage can be reversed by treatment

with large doses of vitamin A but, if un-

treated, blindness is usually inevitable.

keratopathyA general term used to

describe a variety of disorders of the

cornea.Actinic keratopathy is a painful

condition in which the outer layer of the

cornea is damaged by ultraviolet light.

Exposure keratopathy is corneal dam-

age due to loss of the protection

afforded by the tear film and blink

reflex. It may occur in conditions in

which the eyelids inadequately cover

the cornea, including severeexophthal-

mos,facial palsy, and ectropion.

keratoplasty See corneal graft.

keratosisA skingrowth caused by an

overproduction of keratin. Keratoses

occur mainly in elderly people. Sebor-

rhoeic keratoses are harmless growths

that occur mainly on the trunk. The

growths range in appearance from flat,

dark-brown patches to small, wart-like

protrusions. They do not need treating

unless they are unsightly. Solar kera-

toses are small, wart-like, red or

flesh-coloured growths that appear on

exposed parts of the body as a result of

overexposure to the sun over many

years. Rarely, they may develop into skin

cancer, usually squamous cell carcino-

ma, and must be surgically removed.

keratosis pilarisA common condition

in which patches of rough skin appear

on the upper arms, thighs, and but-

tocks. The openings of the hair follicles

become enlarged by plugs of keratin,

and hair growth may be distorted. The

condition occurs most commonly in

KERATOCONJUNCTIVITIS KERATOSIS PILARIS

K

Thin, conical

cornea

Normal

cornea

Lens

KERATOCONUS

NORMAL EYE KERATOCONUS