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An excision of various parts of the cornea.

Inflammation of the cornea. Keratitis is accompanied by conjunctivitis, pain, excessive tearing, photophobia and reduction of vision.

Additional keywords and misspellings:
kerratitis caratitis cornea pain watery light sensitive sensitivity

Keratoconjunctivitis Sicca
The dry cornea and conjuctiva as a result of lacrimal gland dysfunction.

kair ah tow KOH' nuss

Keratoconus is a disorder that occurs when the cornea, which is typically rounded (the front clear part of the eye) becomes cone-shaped. The word keratoconus is formed from two Greek words: kerato, meaning cornea, and konos, meaning cone. Keratoconus, or conical cornea, results in decreased vision due to irregularity of the corneal surface. This distortion has been compared to a distortion in a smeared window. The progression is usually slow and can stop at any stage from mild to severe. The distortion increases as the cornea bulges and thins. As the keratoconus progresses, the apex of the cone often scars, reducing the vision in that eye further. Keratoconus is usually present in both eyes, but may be worse in one eye versus the other.

Who can get it?
Keratoconus appears to have a genetic component. If you have it, you may find that others in your family have it as well.

What are the symptoms?
Because Keratoconus can be difficult to detect and can be combined with astigmatism and nearsightedness, symptoms may not be obvious. Distorted vision which progressively gets worse is typically the most common symptom; something to be aware of is if your prescription seems to change every time you visit your eye care practitioner. Glare and light sensitivity may also be present.

What is the treatment?
Mild keratoconus can often be managed with glasses or soft contact lenses. Frequent visits and careful fitting may be necessary to obtain and maintain good clear vision.

Moderate to severe keratoconus is usually managed with rigid gas permeable contact lenses designed specifically for an irregular corneal surface. The National Keratoconus Foundation reports a 95% success rate with cornea transplants for eyes with severe keratoconus.

An enlarged and globular cornea.

kehr'a-toh-ma-lay' shah

The softening and destruction of the cornea. Usually caused by Vitamin A deficiency or an abnormal metabolism, it is identifiable by a loss of luster to the eye, dryness, and reduced sensitivity.



The keratometer measures the curvature of the cornea. The cornea is responsible for 75% of the focusing of light on the back of the eye (retina). The lens of the eye is responsible for only 25% of the focusing. Therefore, the measurements the keratometer produces are very critical in any calculation involving focusing. The typical range of corneal powers is +0 to 50 diopters. (The typical range of power of IOL is 12 to 20 diopters).

Add'l keywords:
karatometer caratometer kerotomater machinery equipment diagnostic diagnose diopter

Corneal grafting
The EyeCyclopediaâ„¢ is a collection of eye care terminology created by practicing optometrists and ophthalmologists. The information provided is not intended to be a substitute for regular medical care or to diagnose or treat any medical condition, and should be used only as a supplemental source of information. Please consult your doctor if you have any questions or concerns about your eye health.