Keratometric Outcomes after Simultaneous versus Sequential Intracorneal Ring Segment Implantation with Femtosecond Laser and Corneal Collagen Crosslinking in Egyptian Patients with Keratoconus and Ectasia.

BACKGROUND: Keratoconus (KC) is degenerative corneal disorder, with central and paracentral thinning and corneal ectasia. For KC progressive cases, primary treatment included corneal collagen cross linking (CXL) to stabilize coning and intracorneal rings segment (ICRS) to correct visual acuity.

AIM: The aim of the study is to assess efficacy and safety of ICRS and CXL on one session (Simultaneous) or two sessions (sequential) with maximum of 1 month apart.

PATIENTS AND METHODS: This Prospective Intervention Comparative research made at Armed forces hospital, Cairo, Egypt from January 2017 to December 2019. Forty patients (60 eyes) with mild to moderate KC were enrolled. Patients sorted into Simultaneous group includes 21 patients (30 eyes) undergo two procedures (ICRS then CXL) at the same session and Sequential group included 19 patients (30 eyes) undergo ICRS then CXL on two sessions with month apart. Patients followed up at end of 1st , 3rd , and 6th months. Assessment included changes in corrected corneal surface irregularities as minimum keratometric 1 (K1), maximum keratometric readings (K2), and mean keratometric (Km) readings.

RESULTS: Improvement of K1, K2, and Km in Simulations and Sequential groups achieved at end of 1st -, 3rd -, and 6th -month postoperative versus preoperative. Maximum improvement in Simulations and Sequential groups in K1 achieved at end of 6th and 1st months, in K2 at end of 3rd and 6th months and in Km at end of 1st and 3rd months.

CONCLUSIONS: Combined ICRS and CXL act safely in one or two sessions and there are no statistically significant variations between results on both methods in keratometric readings.