Five-year long-term outcomes of intrastromal corneal ring segment implantation using the manual technique for keratoconus management

Purpose: To evaluate the long-term effectiveness, safety, and stability of Ferrara-type intrastromal corneal ring segments (ICRS) by manual surgery implantation in patients with keratoconus. Setting: Ophthalmology Department, Hospital de Braga, Braga, Portugal. Design: Retrospective cohort study. Methods: This study included 124 eyes that had ICRS implantation using the manual technique with a follow-up of 5 years. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), subjective refraction, keratometry, aberrometry, and pachymetry maps were evaluated preoperatively and at 6 months, 1 year, and 5 years postoperatively. A secondary analysis of all variables was performed comparing 2 subgroups of patients: a group younger than 30 years and a group of 30 years or older. Results: At 5 years, both mean UDVA and CDVA improved significantly (P < .0001) from a preoperative value of 0.91 +/- 0.36to 0.46 +/- 0.32 logMAR and 0.40 +/- 0.27 to 0.22 +/- 0.20 logMAR, respectively. Spherical equivalent, refractive cylinder, and all topography values significantly decreased postoperatively (P < .0001). No regression was observed in any visual or topographic parameter during the entire follow-up. Regarding the subgroup analysis, both younger and older patients demonstrated similar and stable results from the preoperative to the 5-year visit, except for minimum pachymetry value change over time. Conclusions: Ferrara-type ICRS implantation significantly improved visual acuity, refractive error, and topographic values; the improvement was stable throughout a 5-year follow-up period. This study confirms that ICRS implantation surgery for keratoconus is a stable procedure in a long-term follow-up, regardless of the preoperative patient's age. J Cataract Refract Surg 2021; 47:713-721 Copyright (c) 2021 Published by Wolters Kluwer on behalf of ASCRS and ESCRS

Automated summary

The study evaluated the long-term effectiveness, safety, and stability of Ferrara-type ICRS implantation by manual surgery in patients with keratoconus. The surgery significantly improved visual acuity, refractive error, and topographic values, and the improvement remained stable throughout a 5-year follow-up period. The procedure was deemed stable regardless of the patient's age, showing no regression in any visual or topographic parameter over time.