To compare visual and refractive measurements of intrastromal corneal ring segments versus toric phakic posterior intra-ocular lenses implantation in keratoconus

• The study is a prospective comparative interventional case series. It will be conducted in Minia university hospital and Roaa Laser Vision Correction Center.
• Fourty eyes will be evenly allocated into two groups:

Group (A): 20 eyes will undergo corneal collagen cross linking (epithelium off) 1 month after Femtosecond laser assisted intrastromal corneal keraring segments.

Group (B): 20 eyes will undergo toric phakic posterior IOL implantation 1 year after corneal collagen cross linking (epithelium off).

• An informed written consent to be involved in the study will be obtained from each patient.

Inclusion Criteria:

• Keratoconus grade I to III according to the Amsler-Krumeich classification

Exclusion Criteria:

• Acute hydrops or grade IV keratoconus
• Any ocular diseases or surgeries
• Corneal thickness less than 400 µm at the thinnest corneal point, and at least 450 µm at the incision site for ICRS group
• Corneal pacities