Magnitude, management outcomes, and determinants of intrastromal corneal ring segment explantation in keratoconus patients at a tertiary eye hospital in Eastern Province Saudi Arabia

Abstract

Purpose: To examine the prevalence of intrastromal corneal ring segment (ICRS) explants, their management outcomes, and determinants in patients with keratoconus at a tertiary eye care center in Eastern province - Saudi Arabia. Methods: This one-armed cohort study included cases of ICRSs explanted at Dharan Eye Specialist Hospital from 2010 to 2020. The type of implant, laterality, corneal thickness, interval between implant and explant, reason for explant, refractive and topographic data, and further actions were recorded. Changes in uncorrected distance visual acuity (UCVA) and the manifest spherical equivalent refraction were the main outcomes. Results: The ICRS explant rate was 5.6% (95% confidence interval 3.6; 7.4). Of the 35 explanted ICRSs, 29 were men (82.9%). The median interval between the ICRS implant and explant was one year (IQR 0.5: 2.4). Intacs (18) and Kerarings (16) were the main types of explanted ICRSs. Dissatisfaction among patients about their vision (11; 31.4%), complications in the cornea (8; 22.9%), problems with implantation (6; 17.1%), and progression of keratoconus (10; 28.6%) were the reasons for explantation. UCVA decline and myopic shift after explantation were noted but they were not statistically significant (P = 0.07). After explantation, 40% needed keratoplasty, while in 28.6% of eyes, the ICRS was reimplanted. The change in UCVA (Mann–Whitney P = 0.74) and manifest spherical equivalent refraction (Mann–Whitney P = 0.87) were not different in the Intact and Keraring ICRS groups. Conclusions: The ICRS explant rate is low. This allows us to delay keratoplasty in 40% of cases by one year. It is still an acceptable option to manage keratoconus in one-quarter of explanted patients.

Keywords

• keratoconus
• intra corneal ring
• cornea
• corneal topography
• keratoplasty