Introduction:
Keratoconus is a progressive, non inflammatory, bilateral (but usually asymmetrical) ectatic corneal disease, characterized by paraxial stromal thinning and weakening that leads to corneal surface distortion. The normal cornea is composed of 6 layers: epithelium, Bowman'slayer, stroma, Descemet'smembrane, and endothelium, Dua's Layer.
The Pentacam HR includes software for densitometry analysis, allowing the intensity of backscattered light from different regions of the cornea to be measured.
The analysis is also performed by depth in 3 layers: the anterior layer, which corresponds to the 120 µm superficial corneal thickness (Superficial layer); the posterior layer, which corresponds to the most posterior 60 µm (Deep layer); and the central, which has no fixed thickness value, is the zone between the anterior and posterior layers (Mid-depth layer). Densitometry is expressed in gray scale units, ranging from a minimum light scatter of 0 (maximum transparency) to a maximum light scatter of 100 (minimum transparency).

Aim:
The aim of the work is to evaluate corneal densitometry in different stages of keratoconus compared to normal corneas using pentacam® HR (Oculus, Wetzlar, Germany).