Secondary Logo

Institutional members access full text with Ovid®

Share this article on:

Clinical Outcomes After Implantation of 320°-Arc Length Intrastromal Corneal Ring Segments in Keratoconus

Torquetti, Leonardo, MD, PhD*; Cunha, Priscila, MD; Luz, Allan, MD, PhD; Kwitko, Sérgio, MD§; Carrion, Márcio, MD; Rocha, Guilherme, MD; Signorelli, Armando, MD**; Coscarelli, Sandro, MD††; Ferrara, Guilherme, MD‡‡; Bicalho, Frederico, MD; Neves, Renato, MD§§; Ferrara, Paulo, MD, PHD‡‡

doi: 10.1097/ICO.0000000000001709
Clinical Science

Purpose: To evaluate the clinical outcomes after implantation of a new 320°-arc length Ferrara intrastromal corneal ring segment (320-ICRS) in eyes of patients with keratoconus.

Methods: A multicentric nonrandomized study was conducted in which a new 320-ICRS was placed in 138 eyes of 130 patients with keratoconus. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, corneal volume, asphericity, lines of vision gain/loss, and vectorial analysis were assessed preoperatively and at the final follow-up visit after the procedure.

Results: The mean follow-up time was 6.2 ± 3.3 (SD) months (range 3–12 months). Mean UDVA improved from 20/250 to 20/60. Mean CDVA improved from 20/100 to 20/40. Mean Q improved from −1.12 ± 0.49 preoperatively to −0.28 ± 0.51 postoperatively (P < 0.001). Mean corneal volume increased from 56.2 ± 4.28 mm3 preoperatively to 57.6 ± 4.74 postoperatively (P < 0.001). Mean Km reduced from 53.3 ± 5.5 D preoperatively to 47.8 ± 4.6 D postoperatively (P < 0.001). The change in UDVA, CDVA, and topographic astigmatism was statistically significant (P < 0.0001).

Conclusions: The 320-ICRS can efficiently and safely improve visual acuity in keratoconus, modifying the corneal shape to a more physiologic, aspheric shape.

*Center for Excellence in Ophthalmology, Pará de Minas, Brazil;

Hospital São Geraldo, HC-UFMG, Belo Horizonte, Brazil;

Hospital de Olhos de Sergipe, Aracaju, Brazil;

§Oftalmocentro, Porto Alegre, Brazil;

Carrion Eye Clinic, Santo Ângelo, Brazil;

Hospital de Olhos de Brasília, Brasília, Brazil;

**Centro Campineiro de Microcirurgia Ocular, Campinas, Brazil;

††Ennio Coscarelli Eye Clinic, Belo Horizonte, Brazil;

‡‡Paulo Ferrara Eye Clinic, Belo Horizonte, Brazil; and

§§EyeCare, São Paulo, Brazil.

Correspondence: Leonardo Torquetti, MD, PhD, Rua Capitão Teixeira, 415-B, Nossa Senhora das Graças-Pará de Minas, MG, Brazil 35660-051 (e-mail:

The authors have no funding to disclose.

The authors have no financial interest in Ferrara intrastromal corneal ring segments, except P. Ferrara and G. Ferrara, who are shareholders of Ferrara Ophthalmics. The other authors have no conflicts of interest to disclose.

Received January 28, 2018

Received in revised form May 31, 2018

Accepted June 02, 2018

Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.