Short Term Outcomes Of 300º Arc-Lenght Intrastromal Corneal Ring Segments Implantation – Six Months Results
Published 2024 - 42nd Congress of the ESCRS
Reference: PP23.13 | Type: Free paper | DOI: 10.82333/w3xv-fv54
Authors: Marta Vaz Pereira* 1 , Christophe Pinto 1 , Mariana Oliveira 1 , José Carlos Mendes 1 , Nuno Franqueira 1 , Fernando Vaz 1 , Tiago Monteiro 2
1Ophthalmology department,Hospital de Braga,Braga,Portugal, 2Ophthalmology department,Hospital de Braga,Braga,Portugal;Ophthalmology department,Hospital CUF Porto,Porto,Portugal;School of Medicine,University of Minho,Braga,Portugal
Purpose
The objective of this study is to evaluate the refractive outcomes, efficacy, and safety of 300º arc intrastromal corneal ring segments (ICRS) implantation in patients with moderate to advanced keratoconus.
Setting
Keratoconus is an asymmetric and progressive corneal ectasia. Irregular astigmatism, high myopia, and associated high-order aberrations significantly impact visual acuity. Intrastromal corneal ring segments have shown good visual outcomes, but traditionally used segments are less effective for moderate to advanced keratoconus. In this context, ICRS with a 300º arc may be a viable alternative in patients with advanced pathology to delay or even prevent the need for keratoplasty.
Methods
A retrospective cohort study was conducted, including 41 patients who underwent ICRS (Ferrara) implantation surgery. The ICRS implantation was performed using either manual or femtosecond-assisted techniques. Visual parameters (uncorrected and corrected visual acuity - UCVA and BCVA, presented in logMAR), refractive parameters (sphere, cylinder, and spherical equivalent), and topographic variables (keratometry, asphericity, coma, and pachymetry) were evaluated. Preoperative and 6-month postoperative visits were considered.
Results
The mean age was 28±11, with 66% being male. Femtosecond-assisted implantation was used in 57.5% of cases. UCVA significantly improved from 1.15±0.28 to 0.75±0.32 (p<0.01), and BCVA improved from 0.90±0.36 to 0.48±0.23 (p<0.01). About 63% of patients improved by at least 2 Snellen lines in BCVA. The safety index was 0.69±0.50, and efficacy index was 1.08±0.89. Refractive parameters improved and remained stable. K1, K2, and Kmax showed a significant decrease. Average anterior keratometry decreased from 52.6D to 46.7D, p<0.01, with improvements asphericity and coma. Posterior tunnel perforation with implant migration to the anterior chamber occurred in 2 patients (4.9%), both using the manual technique.
Conclusions
Implantation of 300º arc ICRS significantly improves visual, refractive, and topographic parameters. However, the retrospective nature, sample size, and short follow-up are factors to be considered and improved in the future.