Keratoconus patients stable over long term with sequential ring segment, IOL implantation

Sequential intrastromal ring segment and monofocal IOL implantation in keratoconus patients showed stable, positive long-term results in a study.

Seventy eyes of 47 patients with keratoconus and cataract were included in the retrospective case series. They were divided into two groups according to the central vs. paracentral location of the cone and implanted with 5-mm and 6-mm apical diameter Ferrara intrastromal corneal ring segments, respectively. According to the degree of topographic astigmatism, one or two rings were implanted and different arc lengths were selected. The ring segment tunnels were created with a femtosecond laser.

Phacoemulsification with implantation of an AcrySof monofocal IOL (Alcon) was performed 6 months after ring segment implantation. Corneal relaxing incisions were performed on the steepest meridian to treat astigmatism.

Uncorrected and corrected distance visual acuity, spherical equivalent and refractive cylinder improved significantly and were stable 6 months, 3 years and 5 years after the sequential procedure.

According to the authors, this was the first study to evaluate this sequential option. Results were overall better as compared with those obtained in previous studies in which cataract surgery or refractive lens exchange with implantation of a toric IOL was performed in keratoconus patients.

“The difference in results could be attributed to the first surgery (ring segment implantation),” according to the authors, because “after [ring segment] implantation, the corneal shape improves.” Although results with toric IOLs might be good, “corneal abnormalities remain present and could decrease visual quality,” they wrote. – by Michela Cimberle

Disclosure: The authors report no relevant financial disclosures.

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Source:

Alfonso JF, et al. J Cataract Refract Surg. 2017;doi:10.1016/j.jcrs.2016.11.044.