Clinics (Sao Paulo). 2017 June; 72(6): 370-377.

Copyright © 2017 CLINICS

Indications and visual outcomes of intrastromal corneal ring segment implantation in a large patient series

Taíse Tognon I II * , Mauro Campos III , João Paulo Wengrzynovski IV , Kleyton Arlindo Barella I , Adriano Pasqualotti V VI , Luiz Antônio de Brito Martins II III , Adriana dos Santos Forseto II III , Luciene Barbosa de Sousa III VII

Instituto Penido Burnier, Campinas, SP, BR

Hospital Oftalmologico de Sorocaba, Sorocaba, SP, BR

Universidade Federal de Sao Paulo, Sao Paulo, SP, BR

Hospital de Olhos do Parana, Curitiba, PR, BR

Universidade de Passo Fundo, Passo Fundo, RS, BR

Universidade de Lisboa, Lisboa, Portugal

Banco de Olhos de Goias, Goiania, GO, BR

*Corresponding author. E-mail:

received August 2, 2016; revised December 16, 2016; accepted April 17, 2017.



To describe the indications for and visual outcomes of intrastromal corneal ring segment implantation.


A large retrospective case-series chart-review study was conducted using Sorocaba Ophthalmological Hospital medical records. This study included 1222 eyes (1196 patients) that were surgically treated between November 2009 and December 2012. The following preoperative data were collected: age, gender, type of medical care and funding source, surgical technique, best-corrected visual acuity, manifest sphere and cylinder refractive error, maximum and minimum central keratometry, and pachymetry measurements of the cornea at the thinnest point and at the ring channel. The postoperative best-corrected visual acuity and patient satisfaction were also determined. The cases were classified into six groups: four keratoconus groups (severe, advanced, moderate and mild), a pellucid marginal degeneration group and a post-graft irregular astigmatism group. This study was approved by the Brazilian Registry of Clinical Trials (UTN number 1111-1182-6181, TRIAL RBR-6S72RF).


The age (mean±standard deviation) of the patients was 31.0±10.0 years. The most prevalent pathology was keratoconus (1147 eyes, 93.8%). A correlation was found between ectasia severity and medical assistance (p<0.001), and the most serious cases was treated by the Brazilian public health system. No complications were found in a total of 1155 surgeries, and after surgery, 959 patients were satisfied. Among the 164 dissatisfied patients, the majority failed to show improved best-corrected visual acuity.


Patients in the public health system underwent surgical intervention for keratoconus later than those with private sources of funding. In the vast majority of operated cases, the patients reported improvements in vision.

Keywords: Epidemiology, Ophthalmologic Surgical Procedure, Cornea, Ectasia, Brazil

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