Abstract
Purpose :
Blue light (short-wavelength light) is a part of the visible electromagnetic light spectrum for the human eye. Short wavelengths have a higher energetic radiation compared to middle and long wavelengths, which might have multiple effects on retinal processes. This study was conducted to investigate whether commonly available screen technologies are able to elicit changes in contrast sensitivity (CS) and therefore may be used to control myopia eventually.
Methods :
In total, 30 right eyes were randomly stimulated with light of different wavelengths: ∼480 nm, ∼530 nm, ∼630 nm and polychromatic light ∼380-780 nm, for 3 min each presented on a liquid crystal display, the ViewPixx/3D (VPixx Technologies, Saint-Bruno, Canada). Light stimulation was performed full field (FF) and only on the optic nerve head (ONH). CS was measured before any stimulation as reference and after each stimulation condition using a new and time-efficient CS test with Gabor patches and the method of adjustment for 3, 6, 12, 18 and 24 cycles per degree (cpd). Changes in CS after stimulation conditions were analyzed by three-way repeated measures analysis of variance. In a priorly conducted complementary study on a subset of five participants, the new CS test was verified to a validated CS test regarding agreement, repeatability (COR) and time.
Results :
The new CS test was used with 3 trials per spatial frequency (interclass correlation coefficient = 0.94, COR = 0.1310 logCS, duration = 92 ± 17 sec). No critical change in CS after stimulation of the eye (FF or ONH) with short-wavelength light was detected (all p > 0.05), see Figure 1. CS measurements regarding spatial frequency differed significantly as expected from the CS function. The results showed, however, that CS differed significantly at 18 cpd after stimulation with polychromatic light from short-wavelength light (p < 0.0001). All other influencing factors and their interactions did not show significant effects.
Conclusions :
The results of using short-wavelength light stimulation via LED screens to increase CS are inconclusive. Based on the results, melanopsin activation and thus increased levels of retinal dopamine are not easy to detect via indirect psychophysical testing. Direct and indirect links of these basic psychophysical findings to retinal signaling and eventually myopia control using short-wavelength light still require further research.
This is a 2021 ARVO Annual Meeting abstract.