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Jose F. Alfonso, Guilherme Ferrara, Carlos Lisa, Arancha Poo, Jesus Merayo-Lloves; Outcome Analyses of Ferrara Intrastromal Corneal Ring Segments (ICRS) in Patients with Keratoconus. Invest. Ophthalmol. Vis. Sci. 2011;52(14):1084.
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© ARVO (1962-2015); The Authors (2016-present)
Outcome analysis of Ferrara ICRS implantation for the orthopedic and refractive management of patient with keratoconus.
Patients: From the date base of 85 eyes of 63 keratoconus patients, 39 men and 24 women with a mean age of 33 years old that underwent surgery with ICRS form a period of 12 months and with a minimal follow up of 3 months, there were select a cohort of patients that meet the following inclusion criteria: keratoconus grade I and II (Rabinowitz) pericentral ectasia (3 to 5 mm from the center of the visual axis), oblique astigmatism (45º right eye and 135º left eye) and axis of coma aberration included from 0º to 75º from the astigmatism axis. Surgery: All patients underwent intrastromal tunelization performed by Femtosecond laser (Intralase) with a specific program (6mm inner and 7.1 mm outer optical zone, 70% of stromal depth, 360º arch and incision at the most curved meridian). ICRS implanted were Ferrara Type (triangular shape, base 800 µm, 6 mm diameter and 150º arch). Outcome analysis measured was mean uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), Orbscan II and CA100 (Topcon) before and 3 months after surgery. Also, the presence of complications (infections, segment removal, extrusion) was analyzed.
Mean UCVA improved from 0,21 ± 0,20 to 0,39 ± 0,28, and the mean BCVA improved from 0,72 ± 0,23 to 0,78 ± 0,20. 50% of the patients gained 1 or more lines of vision, 37,5% remained unchanged and 12,5% of patients had lost 1 line of vision. Orbscan II and CA100 showed corneal flattening, with significant decrease of the keratometry, with mean astigmatism ranging from 3,87 ±1,94 to 2,13 ± 1,49 postoperatively. No complications were observed.
The implantation of Ferrara type ICRS in the keratoconus patient select is effective, safe and have predictable orthopedic and refractive effects. A prospective multicentric study should be performed to confirm our results.
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