Correlation between basal keratometric readings and the keratometric change at 12 months in two pulsed accelerated crosslinking protocols

Abstract

Purpose : To report the correlation between the basal central keratometric readings in patients with progressive keratoconus (KC) and the measured keratometric change at 12 months in two pulsed accelerated crosslinking protocols (pACXL).

Methods : Retrospective comparative cohort of patients with documented progressive keratoconus treated with pACXL and a 12 month follow up were included. Two epi-off pulsed (1/1) aCXL protocols were observed and compared: irradiance 30mW/cm²(pACXL 30:8) during 8 min and 45mW/cm² (pACXL 45:5:20) during 4 min (both with a 0.1% soaking time of 10 min, total energy 7.2J/cm²) (Avedro KXL System, Avedro Inc, Massachusetts, US). Topographic astigmatism and anterior corneal curvature (K_min,K_max,K_m) (Pentacam HR, Oculus, Wetzlar, Germany) were measured preoperatively and months 1,3,6 and 12 postoperative. Statistical analysis was performed using t test, chi-square test, ANOVA and Pearson correlation. Statistical significance was considered with a p value <.05.

Results : A total of 47 eyes (25 patients, 13 females) were included: 23 eyes in Group pACXL 30:8, 24 eyes group pACXL 45:5:20. Mean age(years) and KC stage (Amsler-Krumeich) was 19.09±4.82 and stage 2 and 20.12±4.12 stage 2, (group pACXL 30:8 and 45:5:20,respectively). A significative change (D) in topographic astigmatism, K_min,K_max, and K_mwere observed at the end of the follow up in both groups (p<.001) with no significant difference between groups. A moderate negative correlation was observed between baseline Kmin and DKmin(r=-.473, p=.035),DKm(r=-.506, p=.023), and between baseline Km and DKm(r=-.464, p=.034) in group pACXL 30:8. A moderate-high negative correlation was observed between baseline Kmin and DKmin(r=-.858, p<.001),DKmax(r=-.509, p=.018), Km(r=-.686, p=.001) and between baseline Kmax and DKmin(r=-.885, p<.001),DKmax(r=-.764, p<.001), Km(r=-.818, p<.001) in group pACXL 45:5:20

Conclusions : Both pulsed aCXL protocols improve central keratometric readings in patients with progressive KC at 1 year. A moderate-high negative correlation was observed between baseline keratometric readings and keratometric (D) at 12 months, suggesting an increased effect of corneal crosslinking in corneas with basal steeper curvatures.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.