A blue-light absorbing lens improves visual function under bright light conditions in pseudophakic patients

Introduction: This study evaluated the visual performance of a blue-light filter (BLF). The following visual parameters were assessed: glare disability (GD); chromatic contrast (CC); two-point light thresholds; and dysphotopsia symptoms (halo and spoke diameter). Methods: Twenty-five pseudophakic patients previously implanted with a ‘UV-only’ intraocular lens (IOL) (cut off frequency at 397nm with no visible spectra filtering) were tested using a single-masked randomized cross-over design. In the control condition, a similar UV-only filter (not filtering any visible wavelength) was used. In the test condition, a BLF was used (matching the absorbance profile of a common BLF IOL; Acrysof Natural and Clareon; Alcon Research Ltd). The Intensity of broad-band xenon light (annulus) and a sky-blue background needed to veil a central grating target was used to measure GD and CC, respectively. The diameter of spokes/haloes was determined by measuring their lateral extent induced by a bright white point source. Two-point light thresholds were measured as the separation between two small relatively intense point sources of light (Rayleigh criterion). Results. All of the visual functions measured favored the BLF when compared to the UV-only filter (p<0.001). Conclusion: About 6% and 10% more light energy was needed to occlude the grating stimulus for GD and CC. The light spread measured using the two-point technique was about 26% less for the BLF. The BLF reduced haloing and spokes by about 24% and 19%. The BLF significantly improved function across a variety of visual indices.