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Intrastromal corneal ring segments implantation for keratoconus: clinical, topographic and safety outcomes after 5 years of follow-up

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First Author: C.Pinto PORTUGAL

Co Author(s):    J. Costa   T. Monteiro   N. Franqueira   F. Faria-Correia   R. Freitas   J. Mendes     

Abstract Details

Purpose:

Intrastromal corneal ring segments (ICRS) implantation became a widely accepted surgical treatment for mild-to-moderate stages of keratoconus and corneal ectasia. It has been proposed that ICRS improve myopia and astigmatism with an arc-shortening effect that flattens the central cornea and reduces irregular astigmatism. We conducted this study to evaluate the visual, refractive, topographic and safety outcomes after implantation of ICRS for the management of patients with keratoconus in a long-term follow-up of 5 years.

Setting:

Department of Ophthalmology, Hospital de Braga, Braga, Portugal.

Methods:

This retrospective study included 145 eyes of 116 consecutive patients with keratoconus submitted to Ferrara Ring (Ferrara Ophthalmics, Belo Horizonte, Brazil) ICRS implantation that completed a period of 60-month postoperative follow-up. One or 2 ICRS were inserted in the corneal stroma after mechanical or laser-assisted dissection, embracing the keratoconus area. Variables evaluated included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, keratometric readings, asphericity and coma. Keratoconus phenotypes were recorded. All parameters were accessed preoperatively and at 6, 12 and 60 months postoperatively. Topographic evaluation was performed using Scheimpflug topography Pentacam (Oculus Optikgerate, Wetzlar, Germany).

Results:

Mean UDVA significantly improved from 0,77±0,80 logMAR preoperatively to 0,43±0,64, 0,41±0,62 and 0,37±0,60 logMAR at 6, 12 and 60 months postoperatively. Respectively, mean CDVA increased significantly from 0,35±0,68 logMAR to 0,20±0,70, 0,19±0,68 and 0,17±0,66 logMAR. Manifest sphere and cylinder decreased significantly from -2,11±3,23 and 3,28±1,82 D preoperatively to -0,86±1,90 and 1,48±1,25 D at 6 months. At 6 months, mean K1, K2 and Kmax reduced significantly. All refractive and topographic parameters remained stable during the 5 years. ICRS explantation was performed in 13 eyes (9,0%) due to hypercorrection. Eight eyes (5,5%) showed spontaneous extrusion and three (2,1%) showed endothelial perforation.

Conclusions:

In our series, ICRS implantation revealed to be an effective and safe surgical treatment for keratoconus. In this real-life study, we confirmed the potential of ICRS to restore visual acuity and corneal topography and its ability to stop the progression of corneal ectasia with stable results during the 5-year follow-up period.

Financial Disclosure:

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