Effect of a yellow filter on mesopic contrast perception and differential light sensitivity in the visual field.
OBJECTIVE
Previous studies on the effects of yellow filters in the visual performance have been carried out, presenting discrepancies among the different investigations. Our study reports the influence of the yellow filter without residual reflections on contrast perception and differential light sensitivity (DLS) under mesopic conditions.


METHODS
Contrast sensitivity, low contrast visual acuity and luminance thresholds in the central visual field (30 degrees ) were measured in a group of 38 adult subjects with and without a coated yellow lens (482-nm cut-off) under mesopic conditions.


RESULTS
The contrast sensitivity mean was significantly better with the filter at low- and middle-range spatial frequencies (1.5 cycles/degree p = 0.002 and 6 cycles/degree p = 0.02). At 5% contrast, the mesopic low contrast visual acuity improved significantly (p = 0.004) when interposing the yellow filter. The increase in DLS was statistically significant [e.g. all visual fields p = 0.0003 and macular visual field (9.5 degrees ) p = 0.00001] through the yellow filter on the different established areas of the visual field (30 degrees ).


CONCLUSIONS
The yellow filter without residual reflections had a positive influence on the brightness and contrast perception of healthy subjects, for which its use would be beneficial under mesopic conditions.
Pérez
M J
MJ
Department of Optics, Optic and Optometry School, Complutense University of Madrid, Spain. mjpc@opt.ucm.es
Puell
M C
MC
Sánchez
C
C
Langa
A
A
D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology*; D003623:Dark Adaptation; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008027:Light; D008297:Male; D014792:Visual Acuity / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*