Abstract
Purpose :
Evaluation of contrast sensitivity (CS) in clinical trials of intraocular lenses (IOLs) has long been used as a supplemental measure of image quality. Factors such as IOL design and lighting/glare conditions are known to degrade image quality and reduce CS. While general parameters for CS testing are outlined in ANSI/ISO standards, glare strength (illuminance) is not. ANSI/ISO recommend a level of glare that reduces mean mesopic CS by 0.1 log units at 6 cpd, determined through a pilot study of young, healthy adults. In a previous pilot study, researchers demonstrated that the manufacturer’s standard glare (150 lux) on the Clinical Trial Suite (CTS, M&S Technologies) as well as two attenuated settings (69 and 110 lux) sufficiently reduced the mean CS at 6 cpd by at least 0.1 log units. This study was conducted to compare the effect of the lower glare level on CS for pseudophakic subjects.
Methods :
This was a prospective, non-interventional, multi-center clinical study in adults previously implanted with a TECNIS 1-piece monofocal IOL, Model ZCB00 (at least two months postoperative). Subjects with BCDVA worse than 20/20, posterior capsular opacification, or other adverse ocular/lens findings were not eligible for enrollment. Monocular mesopic CS at 6 cpd with and without standard and attenuated glare (150 and 69 lux, before 1.5 ND filter) was measured using the M&S CTS.
Results :
Monocular data from 88 subjects were evaluated. Mean (SD) mesopic CS without glare was 1.669 (0.288) log units. Under standard and attenuated glare conditions, mean mesopic CS was 1.393 (0.308) and 1.519 (0.324) log units, respectively. This represented a 0.28 and 0.15 log unit decrease in mean mesopic CS under standard and attenuated glare, respectively. This study showed that two different glare levels can both satisfy ANSI/ISO criteria for CS testing. Testing under approximately 50% lower glare illuminance resulted in a near 50% gain in mesopic CS at 6 cpd in monofocal patients.
Conclusions :
ANSI/ISO criteria for CS testing can be met with standard and attenuated glare conditions, based on this study. These findings suggest that CS is highly dependent on glare illuminance, and CS loss due to glare in pseudophakic patients should be carefully interpreted.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.