Clinical Outcomes Of Asymmetric Intrastromal Corneal Ring Segments Implantation For Keratoconus Correction
Published 2024 - 42nd Congress of the ESCRS
Reference: PP01.13 | Type: Free paper | DOI: 10.82333/8sq9-1936
Authors: Rui Silva* 1 , Christophe Pinto 2 , Mariana Oliveira 2 , José Carlos Mendes 2 , Nuno Franqueira 2 , Tiago Monteiro 1
1Hospital de Braga,Braga,Portugal;Escola de Medicina da Universidade do Minho,Braga,Portugal, 2Hospital de Braga,Braga,Portugal
Purpose
Keratoconus is a progressive disorder in which the cornea assumes a conical shape. Corneal thinning induces myopia and irregular astigmatism leading to mild to severe decrease in the quality of vision. Intrastromal corneal ring segments (ICRS) implantation is an effective method for reducing astigmatism and higher-order aberrations. Different types or combinations of ICRSs are available for different phenotypes of keratoconus. While standard ICRS present constant thickness and base width and correct symmetric phenotypes uniformly, they are insufficient in asymmetric patterns that require more flattening in some portions of the cornea. The aim of this study was to evaluate the clinical outcomes in patients implanted with asymmetric ICRS.
Setting
Cornea and Anterior Segment Department, in Hospital de Braga, Braga, Portugal.
Methods
Prospective study, comprising patients with asymmetrical paracentral keratoconus (Duck or Snowman Phenotype) who had asymmetric intrastromal corneal ring segments implantation (AJL PRO +, AJLÒ Spain). Manual dissection or femtosecond laser were performed for tunnel creation. The main outcome measures evaluated at 6 months follow-up were: uncorrected (UDVA) and corrected distance visual acuity (CDVA), aberrometric, and topometric indexes. Efficacy and safety indexes were calculated based on UDVA and CDVA data.
Results
This study evaluated 23 eyes (21 patients) with a mean age of 29 ± 11.3 years at the time of surgery. Duck was the most common phenotype (18 eyes) followed by snowman (5 eyes). ICRS implantation significantly both improved UDVA and CDVA from 0.57 ± 0.13 to 0.31 ± 0.19 (p=0.001) and from 0.35 ± 0.16 to 0.13±0.13 (p<0.001), respectively. The refractive astigmatism significantly decreased, from -2.00 ± 0.93D to -0.88 ± 0.78D (p=0.001). Regarding keratometry readings, K2 decreased from 48.64 ± 2.97 D to 46.89 ± 3.08 D (p=0.002). Coma aberration was significantly reduced from 2.15 ± 0.17 to 1.31 ± 0.10 (p<0.001). Safety and Efficacy index were higher than 1.0. No intra or postoperative complications were observed.
Conclusions
The implantation of asymmetric ICRS (AJL PRO +, AJLÒ, Spain) of variable thickness and base width provided good visual, refractive and topographic outcomes, indicating that it is a predictable procedure for refractive correction of asymmetric keratoconus.