The use of two 90-degree arc intracorneal ring segments in management of crab-claw topographic pattern

Abstract

BackgroundKeratoconus and pellucid marginal degeneration (PMD) are bilateral, progressive, and ectatic corneal disorders characterized by thinning of the cornea.AimTo assess the visual and refractive outcome of using two 90-degree arc intrastromal corneal ring segments (ICRS) in the management of crab-claw topographic pattern.Patients and methodsThis study included 17 eyes of nine patients with crab-claw topographic patterns, either pellucid-like KC or PMD, needing ICRS. Preoperative evaluation included detailed ocular history, full ophthalmic examination, including uncorrected visual acuity (UCVA), manifest refraction, best spectacle-corrected visual acuity, and Pentacam.ResultsRegarding visual outcome, the mean UCVA improved significantly from 0.12 ± 0.09 to 0.86 ± 0.16 postoperatively (P < 0.001). The UCVA improved in all eyes (100%). The mean best spectacle-corrected visual acuity in LogMAR improved significantly from 0.31 ± 0.18 to 0.91 ± 0.11 postoperatively (P < 0.001). The mean cylinder was −8.00 ± 1.30 preoperatively that improved to −1.50 ± 1.00 at the end of the follow-up (P < 0.001), while the mean sphere improved nonsignificantly from + 2.00 ± 1.00 to + 2.50 ± 1.00 postoperatively.ConclusionTwo 90-degree arc ICRS implantations are a safe and efficient surgical option in the management of patients with crab-claw topographic patterns, which was either PMD or pellucid-like KC with a good visual and refractive outcome.