Long-term outcomes of bandage therapeutic-optical keratoplasty in the treatment of keratoconus

Abstract

Evaluation of the long-term outcomes of surgical treatment of stages II and III progressive KC with BTOK technique. The study included 107 patients (126 eyes): group 1 with stage II KC - 78 eyes, 100% of these patients were observed for 1 year, 52 eyes (66%) for 3 years, and 18 eyes (23%) for 5 years; group 2 - 48 eyes with stage III KC, with 100% of them observed for 1 year, 39 eyes (81%) for 3 years, and 12 eyes (25%) - 5 years. All patients received a customized allograft in the form of an intrastromal corneal ring segment (ICRS). During the first year after BTOK surgery, the uncorrected and corrected visual acuity (UCVA and CVA) in the first group increased by 0.5±0.04 (p<0.05) and 0.2±0.02 (p<0.05), respectively, in the second group - by 0.46±0.05 (p<0.05) and 0.47±0.05 (p<0.05) due to a decrease in refractive indices in the central 3.0 mm zone. In the first group, mean refraction in the central 3.0 mm zone (Km) was within 45±3.75 (p<0.05), in the second - 48.63±.2 diopters (p<0.05), while maximum refraction in the central 3.0 mm zone (Kmax) decreased from 50.02±2.20 (p<0.05) to 44.61±1.03 diopters (p<0.05) in the first group, from 58.21±3.43 (p<0.05) to 50.45±3.46 diopters (p<0.05) in the second group. The values of UCVA, CVA and refractive indices of the central corneal zone in the first and second groups did not change statistically significantly after three and five years. Minimum corneal thickness in the first group increased from 476.23±13.35 to 485.08±15.80 µm (p<0.05), in the second - from 412.73±38.63 to 422.00±42.25 µm (p<0.05). BTOK surgery can be used in patients with stages II and III KC to improve the visual functions, strengthen the ectatic cornea and stop the progression of the disease.