Abstract
Purpose :
Lenslet-type optics utilized in myopia-control spectacle lenses (MCSL) has been shown to cause minimal impact on visual performance under conventional clinical light conditions (Li et al, 2021). Whether lenslet features introduce visual artefacts under more severe conditions such as glare has not been tested. This study explored the feasibility of a glare tester (GT) to detect and discriminate between MC lenses.
Methods :
A GT based on that of Buhren et al (2006) was constructed to measure Glare Effect (GE) on contrast sensitivity (CS), consisting of a ring of 8 equally-spaced 6400 mcd LEDs, positioned on a dark base board. A square aperture at the centre of the LED ring enabled viewing of test charts displayed on an electronic vision chart (EVC) monitor (Sony LMD-DM20) 6 metres from the participant. The ring of LEDs subtended an angle of 6.4° at the participant’s eye. The participant viewed Pelli Robson CS letters displayed on the EVC. Letter sizes tested were 6/38, 6/24, 6/15 and 6/9.5. CS for each letter size was measured monocularly under mesopic (<8 lux) and photopic (380–400 lux) conditions with and without LED-induced glare for two commercially-available MCSL (Hoya MiYOSMART and Essilor Stellest) and habitual correction for 4 participants and were instructed to view through the lenslet region of the lenses. A glare effect quotient (GE, Figure 1 equation) was calculated as a measure of device-induced glare relative to habitual correction. General linear model was used to account for the effect of lens type, light and letter size on GE. 95% CI was used to determine the difference from habitual correction.
Results :
Participants age range was 25 to 39 years. The 95% CI showed that MiYOSMART lens had a similar or better contrast sensitivity when compared to habitual correction for all letter sizes under both illumination conditions (Table 1). Although not statistically significant, reduction in CS by 0.02 log10 units was observed at 6/38 for the Stellest lens under both light conditions and in photopic condition a minimal reduction in CS was noted at 6/9.5. At 6/15, the MC devices had similar CS increase of around 0.05 log10 units.
Conclusions :
This small-sample exploratory study suggests that a GT can identify differences in participant performance of MCSL under glare conditions. With further refinements, a GT may be useful in determining the vision acceptability of MCSL.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.