Intrastromal corneal ring segments delay corneal grafting in patients with keratoconus

Abstract

Approved by the following research ethics committee: Hospital das Clínicas, Universidade Federal de Goiás (219.191). ABSTRACT Purpose:To assess the impact of intrastromal corneal ring segments (ICRS) as a surgical alternative to corneal grafting in patients with keratoconus who were scheduled for a corneal transplant. Methods: This single-surgeon, single-center, retrospective, observational case series study included 19 eyes of 18 patients (mean age, 23.36 ± 6.22 years) with a confirmed diagnosis of keratoconus. These patients were enrolled from the State of Goiás, Brazil corneal graft waiting list. Following extensive pre-operative testing, including the measurement of best-corrected visual acuity (BCVA), applanation tonometry, biomicroscopy, funduscopy, pachymetry, and corneal topography, patients were implanted with Keraring® ICRS. Patients underwent clinical examination at postoperative days 1, 7, 30, 90, and 180 and were examined again 2 years following surgery. Results: At the 2-year cut-off following ICRS implantation (mean follow-up, 28.72 ± 4.71 months), there was a statistically significant improvement in BCVA (logMAR) from 0.59 ± 0.35 preoperatively to 0.35 ± 0.45 postoperatively (p<0.01). Three of 19 eyes (15.8%) still required keratoplasty. In the remaining patients (84.2%), BCVA was managed with spectacles (52.6%) or contact lenses (31.6%). One patient developed infectious keratitis, requiring removal of ICR at the first postoperative visit. Conclusion: ICRS implantation may be a surgical alternative to keratoplasty in patients with keratoconus. This procedure may delay or even eliminate the need for keratoplasty in such patients.

Efficacy of Different Procedures of Intra-Corneal Ring Segment Implantation in Keratoconus: a Systematic Review and Meta-Analysis

“…1). Removal of duplicates and use of the selection criteria reduced the number of articles reporting the evaluation of ICRS in keratoconus to 95 articles 8,14–16,26…”

“…The assessment of the quality of the 95 studies that were included was performed using the STROBE criteria, with the results varying from 43.8%31 to 93.8%,41,66–68,70,103 with a mean score of 79.7 ± 8.8. Overall, the studies performed best in the methods section and worst in the discussion section.…”

Bandage Therapeutic-Optical Keratoplasty in Keratoconus Patients after Intrastromal Corneal Segments Implantation

“…Так, есть данные об увеличении НКОЗ в 93 % случаев, снижении рефракции роговицы в центре во всех случаях, сохранении стабильности эффекта в течение 5 лет у всех пациентов с кератоконусом [12]. В то же время в других работах указано, что эффект действия РС не столь продолжителен и может исчезать при сроке 2 и более лет после операции, что отмечено в 80 % случаев [13][14][15] литература/rEfErEnCEs…”

Ferrara Intrastromal Corneal Ring Segments

“…[1][2][3][4][5][6] Besides, the ICRS are a surgical alternative to at least delay, if not eliminate, the need for lamellar keratoplasty or penetrating keratoplasty (PKP). 7 In 1986, Ferrara started implanting modified polymethylmethacrylate (PMMA) ICRS in rabbit corneas, and in 1994, he developed a better technique of corneal tunnel construction for implanting the ICRS. 8 The Ferrara ICRS are made of PMMA Perspex camphorquinone (CQ) acrylic segments.…”

“…Many studies have demonstrated the efficacy of ICRS to treat many corneal conditions as keratoconus, [1][2][3][4][5][6][7] post-LASIK corneal ectasia, 9,10 postradial keratotomy ectasia, 11 astigmatism, 12 and myopia. [13][14][15] The changes in corneal structure induced by additive technologies can be roughly predicted by Barraquer's thickness law, which states that when material is added to the periphery of the cornea or an equal amount of material is removed from the central area, a flattening effect is achieved.…”