Competing/conflicts of interest: No stated conflict of interest.
Intrastromal corneal ring segments: visual outcomes from a large case series
Article first published online: 25 JUL 2012
© 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists
Clinical & Experimental Ophthalmology
Volume 40, Issue 5, pages 433–439, July 2012
How to Cite
Ferrara, G., Torquetti, L., Ferrara, P. and Merayo-Lloves, J. (2012), Intrastromal corneal ring segments: visual outcomes from a large case series. Clinical & Experimental Ophthalmology, 40: 433–439. doi: 10.1111/j.1442-9071.2011.02698.x
Funding sources: Dr Paulo Ferrara, Dr Guilherme Ferrara and Dr Jesús Merayo-Lloves have financial interest in the Ferrara Ring. Dr Leonardo Torquetti has no financial interest.
- Issue published online: 25 JUL 2012
- Article first published online: 25 JUL 2012
- Accepted manuscript online: 8 SEP 2011 12:17PM EST
- Received 9 July 2011; accepted 15 August 2011.
- corneal topography;
Background: To evaluate the clinical safety and efficacy of implanted Ferrara intrastromal corneal ring segments in a large sample of patients with ectatic corneal disease.
Design: Retrospective, consecutive case series.
Samples: A total of 1073 eyes of 810 patients consecutively operated from January 2006 to July 2008 were evaluated.
Methods: Two groups were created according to the type of ring implanted: Group 1 – patients implanted with the 160° of arc ring – and Group 2 – patients implanted with the 210° of arc ring.
Main Outcome Measures: Uncorrected visual acuity, best-corrected visual acuity, keratometry, asphericity and pachymetry at the thinnest point of the cornea. All patients were evaluated using a corneal tomography (Pentacam, Oculus, Inc., Lynnwood, WA, USA).
Results: For Group 1 patients, uncorrected visual acuity increased to 20/80, best-corrected visual acuity increased to 20/40, asphericity decreased to −0.35, spherical equivalent decreased to −2.26 D and keratometry decreased to 45.72 D (P < 0.001 for each compared with preoperative values). For Group 2 patients, uncorrected visual acuity increased to 20/130, best-corrected visual acuity increased to 20/60, asphericity decreased to −0.56, spherical equivalent decreased to −4.14 D and keratometry decreased to 48.10 D (P < 0.001 for each compared with preoperative values). The 210° intrastromal corneal ring segments reduced keratometry and asphericity more than the 160° intrastromal corneal ring segments did. The complication rate was 3.82%.
Conclusions: Ferrara intrastromal corneal ring segments implantation is safe and effective and has a low complication rate. It can effectively reduce the corneal steepening and improve uncorrected visual acuity and best-corrected visual acuity in patients with keratoconus.