Clinical Outcomes of a New Type of Continuous Intrastromal Corneal Ring for Treatment of Keratoconus

Abstract

Purpose:The purpose of this study was to evaluate the efficacy and safety of implantation of a new continuous corneal ring in keratoconic corneas of an Iranian population.Methods: This study was conducted on 95 contact lens-intolerant keratoconic eyes with clear central corneas. A continuous corneal ring, annular intrastromal corneal inlay (AICI), was inserted using femtosecond laser in all cases. Patients were followed up for 1, 3, and 12 months postsurgery. Visual and subjective refractive outcomes were evaluated in each examination. Besides, keratometry and aberrometric values were recorded before and 12 months after surgery. Finally, vector analysis of refractive astigmatism was performed using the Alpins method. Results:The uncorrected and corrected distance visual acuities improved significantly 12 months after surgery from 0.91 6 0.39 to 0.38 6 0.22 (P , 0 0.001) and 0.33 6 0.21 to 0.13 6 0.11 logMAR (P , 0.001), respectively. Moreover, spherical and cylindrical refractive components reduced from 22.52 6 2.62 to 20.76 6 1.78 D (P , 0.001) and 24.14 6 1.64 to 21.91 6 1.18 D (P , 0.001), respectively. The mean anterior keratometry had a significant reduction 12 months after AICI insertion (P, 0.001). Primary coma and spherical aberration values showed a significant increase (both, P , 0.05). Our results showed 100% safety (safety index: 1.8) and 45% efficacy (efficacy index: 1).Conclusions: AICI implantation seemed to be a safe and effective procedure for improving visual acuity and refractive outcomes in subjects with keratoconus.

Comparison of two different 360-degree intrastromal corneal rings combined with simultaneous accelerated-corneal cross-linking

“…This placement method is sutureless and could produce a balanced pressure over the corneal tissue. 11,42 Intraoperative stromal pockets could be created using a mechanical or femtosecond laser-assisted procedure. Most studies published before 2010 utilized the mechanical approach as a pocket creation procedure.…”

“…However, the long-term effects of combined AICI and A-CXL on visual, refractive, and tomographic measurements have not been investigated. In another study, Jabbarvand et al 11 evaluated the efficacy and safety of AICI implantation by comparing pre- and postsurgical (one year) visual, refractive, aberrometric, and topographic outcomes in 95 KCN patients. They reported improvements in all parameters and the safety and efficacy of 100% (safety index: 1.8) and 45% (efficacy index: 1), respectively.…”

“…12 The designer of this ring (M.J) claimed that this new design has a thinner profile and more desirable curvature than other ICRS, contributing to favorable postsurgical outcomes and fewer complications. 11 Despite the uncertain reports regarding the effectiveness of CXL in improving uncorrected vision in most KCN cases, 3 its combination with other refractive surgery methods could enhance the visual outcomes of the procedure. 2,4,13,14 The unique capabilities of ICRS and CXL in vision improvement and slowing down the progression of the KCN resulted in a combined therapeutic approach (CXL plus ICRS) to improve corneal biomechanics and stability.…”

“…An advanced type of continuous annular intracorneal implant (labelled as AICI, Ophthalight cor., Tehran, Iran) has also been recently marketed. 10,11 This annular-shaped intracorneal implant (AICI) is a one-piece ring with a rectangular cross-section in different thicknesses for vision improvement of KCN in various stages. 12 The designer of this ring (M.J) claimed that this new design has a thinner profile and more desirable curvature than other ICRS, contributing to favorable postsurgical outcomes and fewer complications.…”

“…12 The designer of this ring (M.J) claimed that this new design has a thinner profile and more desirable curvature than other ICRS, contributing to favorable postsurgical outcomes and fewer complications. 11…”