New research suggests that intrastromal corneal ring segment (ICRS) implantation can significantly improve visual acuity, refractive error and topographic value in patients with keratoconus. The investigators noted that the improvement persisted throughout a five-year follow-up period.

The retrospective cohort study included 124 eyes that had ICRS implantation using a manual surgery technique. The team evaluated uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), subjective refraction, keratometry, aberrometry and pachymetry preoperatively and at six months, one year and five years postoperatively. They also performed a secondary analysis of all variables comparing two subgroups of patients: a group younger than 30 years and a group older.

At five years, both mean UDVA and CDVA improved significantly from preoperative values of 0.91MAR and 0.40logMAR, respectively, to postoperative values of 0.46logMAR and 0.22logMAR, respectively. Spherical equivalent, refractive cylinder and all topography values significantly decreased postoperatively. The researchers did not observe regression 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 five-year visit.

“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,” the study authors concluded in their paper.

Costa JV, Monteiro T, Franqueira N, et al. Five-year long-term outcomes of intrastromal corneal ring segment implantation using the manual technique for keratoconus management. J Cataract Refract Surg. 2021;47(6):713-21.