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Advanced Techniques
Keratoconus

Keratoconus is a degenerative hereditary condition of the cornea. It results in a progressive thinning of the central or paracentral area of the cornea and is accompanied by irregular astigmatism. In more advanced cases the cornea can form a bulge or a �cone� which is often located near or just below its center. In other cases a diffuse thinning of the cornea can result in a �sagging cone� otherwise known as Keratoglobus.

Advanced keratoconus may be divided into two principal clinical categories: the round or nipple-shaped cone and the oval or sagging cone. The round cone is the most common type and typically lies in the lower nasal quadrant. The sagging cone is usually longer and steeper than the round cone. It sags in the inferotemporal quadrant with an average reading of 68 D. The round cone is rarely greater than 65 D and it responds more favorably to contact lens fitting.

A diffusely thinned cornea with generalized bulging and no defined cone.

 

Nipple Cone.

 

Sagging Cone.

 

The severity of keratoconus may be classified according to the following table:

The Dioptric Powers Indicated Are Found
at the Apex of the Cone
-
Mild
Moderate
Advanced
Severe
K Reading <45.00 D >45.00 D >52.00 D >60.00 D

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