Evaluation of Short-Term Color Vision Perception Changes After Using a Repeated Low-Level Red-Light Therapy Myopia...

Repeated low-level red-light (RLRL) therapy is an emerging technique for managing myopia progression. Clinical trials have demonstrated its efficacy, but uncertainties remain on its effect on immediate vision perception. This study evaluated the impact of RLRL on short-term color vision perception and choroidal thickness. Attitudes towards RLRL were also explored.

Twenty participants underwent color vision assessment using the Colour Assessment Diagnosis (CAD) test and macular optical coherence tomography (OCT) to determine their eligibility and establish baseline measures for color vision perception threshold and choroidal thickness, with color vision perception measured using chromatic displacement (CD). Participants then underwent three sessions of RLRL, at the required time intervals as per manufacturer guidance. After each session, the CAD test was performed immediately, and repeated after a 5-minute interval. At the final visit, the OCT scan was retaken, and participants were asked about their experience of using RLRL. CD was measured and compared before and after RLRL exposure, to identify if there was any differences following usage.

A significant reduction in color perception sensitivity was observed immediately after exposure to RLRL at each visit (p < 0.001 for all), which returned to baseline levels after 5 min. Three sessions of RLRL caused no change compared to baseline color perception (p = 0.054). There was no significant difference in the mean choroidal thickness in the left eye; the right eye showed a small reduction in macular choroidal thickness 5.1 µm (± 8.551 µm SD, p = 0.015). Participant feedback demonstrated a generally positive response, indicating people would consider using RLRL for myopia management if recommended.

There appears to be only a temporary impact of RLRL on color vision perception, which returns to baseline after 5 min. Furthermore, feedback suggests that UK populations may be receptive to RLRL if prescribed to them by an eye care practitioner.