Femtosecond Laser Implantation of a 355-Degree Intrastromal Corneal Ring Segment in Keratoconus: A Three-Year Follow-Up

Table 5

The efficacy index and safety index of the procedure.

	3 months	6 months	12 months	24 months	36 months
Safety index	2.27	2.27	1.95	1.81	1.70
Efficacy index	1.59	1.59	1.45	1.32	1.09