Materials and Methods: This is a retrospective study included 53 eyes of 28 patients aged between 16 and 40 years with keratoconus who underwent corneal riboflavin induced UV-A CXL. Slit-lamp examination, visual acuity tests in a decimal scale converted to logMAR data, central corneal thickness (CCT), and intraocular pressure (IOP) measurements were performed. Corneal topography was used to examine the maximum K value of the apex (Kmax), the minimum K value of the apex (Kmin), Sim K, anterior chamber depth (ACD), Kappa angle, mean power and astigmatic power in the 3.0 mm and 5.0 mm central corneal zone at 1th, 6th and 12th months.

Results: The mean age of the patients was 24.26 ± 5.06 years (range of 16-40 years). Follow-up period was 1 year. There was a reduction in the Kmax value at the end of 1 year by 1.15 D (p <0.001). There was a decrease in the CCT in 1th month 445.69 ?m to 391.09 ?m and then to 404.47?m in postoperative 12th month (p <0.001). The mean ACD was 3.26±0.23 mm preoperative and increased to 3.31±0.23 mm at 1th month, 3.30±0,25mm at 6th month and 3.29±0.24 mm at 12th months (p<0.001, p=0.021, respectively). There was no difference in kappa angle between the follow-up times.

Conclusion: CXL is a safe and effective technique to prevent the progression of keratoconus and also effective in delaying or reducing the need of the surgery. Keywords : Corneal Cross linking, Keratoconus, Riboflavin A, Kmax, Anterior chamber depht