The purpose of this study is to postpone the corneal transplantation in keratoconus and promote the stiffness of the cornea across the riboflavin-UVA corneal collagen crosslinking , and after, corneal ring surgery.

Keratoconus is a progressive disease where cornea is thin and has a higher curvature.In early conditions, it may be corrected by glasses or contact lens.When these possibilities are not more possibles, it may be corrected by corneal ring surgery ore corneal transplantation depending your degree.

In this study, the patients with a degree of keratoconus on I or II, will be submitted to corneal collagen crosslinking and then a corneal ring surgery.

The corneal collagen crosslinking promote the stiffness of the cornea across the riboflavin-UVA irradiation, avoid the progression of the keratoconus.After three months of crosslinking, these patients will be submitted a corneal ring surgery.

These patients will be allowed by two years and various exams will realized them.

Inclusion Criteria:

• Patients with keratoconus
• Patients that aren't using contact lenses
• Pachymetry more than 400Um
• Best visual acuity less or equal 20/30

Exclusion Criteria:

• Ocular surgeries before
• Other eye diseases
• Corneal curvature more than 65 dioptres