Cornea congenital anomalies

Megalocornea
Horizontal diameter of cornea at birth is about 10 mm and the adult size of about 11.7 mm is attained by the age of 2 years. Megalocornea is labelled when the horizontal diameter of cornea is of adult size at birth or 13 mm or greater after the age of 2 years. The cornea is usually clear with normal thickness and vision. The condition is not progressive. Systemic association include Marfan's, Apert, Ehlers Danlos and Down syndromes.

Differential diagnosis
1. Buphthalmos. In this condition IOP is raised and the eyeball is enlarged as a whole. The enlarged cornea is usually associated with

cornea anatomy

APPLIED CORNEA ANATOMY
The cornea is a transparent, avascular, watch-glass like structure. It forms anterior one-sixth of the outer fibrous coat of the eyeball.

Dimensions

• The anterior surface of cornea is elliptical with an average horizontal diameter of 11.7 mm and vertical diameter of 11 mm.
• The posterior surface of cornea is circular with an average diameter of 11.5 mm.
• Thickness of cornea in the centre is about 0.52 mm while at the periphery it is 0.7 mm.
• Radius of curvature. The central 5 mm area of the cornea forms the powerful

pinguecula

Pinguecula is an extremely common degenerative condition of the conjunctiva. It is characterized by formation of a yellowish white patch on the bulbar conjunctiva near the limbus. This condition is termed pinguecula, because of its resemblance to fat, which means pinguis.

Etiology of pinguecula is not known exactly. It has
been considered as an age-change, occurring more
commonly in persons exposed to