Results of Follow-up in Pediatric Keratoconus Treated With Intracorneal Ring Segments Implantation Alone or in Combination With Corneal Cross-linking

Abstract

Purpose: To report visual and topographic outcomes of pediatric keratoconus with intracorneal ring segments (ICRS) implantation alone or in combination with accelerated corneal cross-linking (A-CXL). Methods: A descriptive, retrospective observational study was performed. Medical records of patients younger than 18 years at Fundación Oftalmológica Nacional in Bogotá, Colombia, were reviewed. Demographic data, follow-up time, preoperative and postoperative uncorrected (UCVA) and best corrected (BCVA) visual acuity, manifest refraction, and tomography were evaluated. SPSS software (version 22.0; SPSS, Inc) was used for analysis. Results: Twenty-six eyes of 19 patients with a mean age of 16.5 ± 1.8 years were analyzed, and 16 were boys (84.2%). Median follow-up time was 39.6 months (inter-quartile range [IQR] = 30). Fifteen patients (78.9%) had a history of allergic conjunctivitis. Sixteen eyes (61.5%) received ICRS implantation with A-CXL and 10 eyes (38.4%) received ICRS implantation only. Global results (including ICRS implantation with A-CXL and ICRS implantation only) were: (1) median UCVA of 0.90 logarithm of the minimum angle of resolution (logMAR) (IQR = 0.85) preoperatively improved to 0.54 logMAR (IQR = 0.70) postoperatively; (2) median BCVA of 0.43 logMAR (IQR = 0.39) preoperatively improved to 0.30 logMAR (IQR = 0.26) postoperatively; and (3) median spherical equivalent of −5.37 diopters (D) (IQR = −5.28) preoperatively improved to −4.12 D (IQR = −3.57) postoperatively. There was a reduction in half of the sphere and cylinder. The median maximum keratometry was 54.40 D (IQR = 7.4) preoperatively and 49.80 D (IQR = 5.3) postoperatively. The median asphericity was −1.18 (IQR = 0.70) preoperatively and changed to −0.75 (IQR = 0.68) postoperatively. No patient presented with complications before or after surgery. Conclusions: ICRS implantation only or in combination with A-CXL induced visual and topographic improvement in patients with keratoconus, which was maintained throughout the follow-up time. It seems to be a safe procedure to delay or avoid corneal transplantation in the pediatric population. [ J Pediatr Ophthalmol Strabismus . 2022;59(2):118–127.]

Effect of intrastromal corneal ring segments on in vivo corneal biomechanics in keratoconus: 1-year results

“…This finding is in agreement with previous literature. [6][7][8][9][10][11] The main strengths of this study include its prospective design, the long-term follow-up, and the use of new DCRs, which have been shown to be independent of IOP and tissue thickness. The main limitation of this study is the fact that the Corvis measures only 1 horizontal meridian while most ICRSs are implanted inferiorly.…”

“…However, there are some controversies regarding whether ICRSs alone are able to stop KC progression, with some studies demonstrating long-term efficacy and stability of ICRSs while others showing the opposite. 6–10,21…”

“…However, there are some controversies regarding whether ICRSs alone are able to stop KC progression, with some studies demonstrating long-term efficacy and stability of ICRSs while others showing the opposite. [6][7][8][9][10]21 Among these studies, very few assessed the induced biomechanical changes, which are of foremost importance, given the pathophysiology of the disease. We previously published that ICRS implantation does not affect IOP or corneal biomechanics measurements of the Corvis in early follow-up, which was an expected result, given the fact that rings do not alter the biomechanical properties of the cornea.…”

“…1 This new stress distribution can interrupt the cycle of decompensation and has shown long-term improvement of corneal morphology and refraction, an increase in visual acuity, and an excellent safety profile even in pediatric patients, where the risk of KC progression is higher. [6][7][8][9][10][11] It has been reported that there is no change in properties with intrastromal rings with the ocular response analyzer. 12 Similarly, we published that intrastromal corneal ring segment (ICRS) implantation does not affect corneal biomechanical measurements from the Corvis in early follow-up.…”

“…1 This new stress distribution can interrupt the cycle of decompensation and has shown long-term improvement of corneal morphology and refraction, an increase in visual acuity, and an excellent safety profile even in pediatric patients, where the risk of KC progression is higher. 6–11…”