Low light visual function after accelerated corneal Cross-Linking Protocols: 18 mW/cm2 vs. 9 mW/cm2

Abstract

Objective. To compare one-year results of vision, corneal aberrometry and contrast sensitivity (CS) in low light conditions between 5-and 10-minute accelerated crosslinking (CXL) protocols. Methods. Thirty eyes were evaluated in each studied group. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity by the SC-2000 Snellen chart, corneal higher order aberrations using the OPD Scan III and CS using MonCv3System was tested under mesopic (20 lux) and scotopic (0.5 lux) light conditions at pre-CXL and 6 and 12 months post-CXL. Results. At 12 months, a mean improvement of 0.06±0.22 (22.2%) and 0.02±0.25 logMAR (7.9%) in mesopic UDVA and 0.01±0.13 (14.3%) and 0.07±0.13 logMAR (87.9%) in mesopic CDVA was observed in the 5-and 10-minute groups, respectively. Mean decline in scotopic UDVA was 0.01±0.16 (1.0%) and 0.03±0.17 logMAR (11.9%) and mean improvement in scotopic CDVA was 0.03±0.10 (35.5%) and 0.02±0.07 logMAR (22.2%), respectively. Inter-group differences in the decrease of corneal aberrations were not statistically significant. Among CS variables, only inter-group changes in corrected CS 0.5 to 2.2 was significantly different (all P<0.050). The linear regression analysis showed that these differences were related to baseline values not CXL protocols; corrected CS 0.5 (Pgroup=0.261 and Pbaseline value<0.001), CS 1.1 (Pgroup=0.250 and Pbaseline value<0.001), and CS 2.2 (Pgroup=0.101 and Pbaseline value=0.054). Conclusions. Changing the intensity of UV in cross-linking from 18mW/ cm2 to 9mW/ cm2 does not affect the visual function under low-light conditions.

Accelerated Corneal Collagen Cross-Linking Protocols for Progressive Keratoconus: Systematic Review and Meta-analysis

“…Enrolled subjects were assigned to either the 18 mW/cm 2 for 5-minute protocol (30 eyes from 22 patients) or 9 mW/cm 2 for 10-minute protocol (30 eyes from 24 patients). 15…”

“…Several studies have compared the effectiveness of 10- and 5-minute protocols. 12–15 However, there are currently no systematic reviews or meta-analyses comparing the outcomes of these 2 interventions. This study is the first to report these outcomes.…”

A review of imaging modalities for detecting early keratoconus

“…The OPD scan also provides optical path difference (OPD) maps which detects total refractive error in the eye as well as the refractive error contributed by the internal structures of the eye [26]. The NIDEK OPD scan has been used to evaluate the quality of vision in patients with keratoconus after corneal transplants [27], after intracorneal ring segment implantation [28], and after accelerated corneal cross-linking [29]. Asgari et al evaluated mild and moderate keratoconus eyes after accelerated cross-linking and found that the OPD scan III had higher aberrometric repeatability in mild compared with moderate cases [30].…”