Effect of filters on the accommodation and colour discrimination

Abstract

AbstractPurpose: To evaluate the effect of coloured filters on the accommodative response and colour discrimination in young subjects.Methods: Two long pass filters (LED light reduction and 511 nm filter), two selective absorption filters (ML41 and emerald filter), and no filter condition were evaluated. The photorefractor PowerRef3 (PlusOptix) was used to measure the objective refraction at 3 different distances (40, 100, and 400 cm). The measurement obtained at 400 cm was used as a reference to calculate the accommodative response. The fixation target consisted of five letter length words (size corresponding to 6/12 Snellen) that were presented in black font over white background. Words changed with a frequency of 2 Hz according to the rapid serial visual presentation paradigm. The Cambridge Colour Test (Metropsis) was used to measure the discrimination threshold in a 10‐vector ellipse at a 3 m viewing distance. The measurement was repeated twice, and it was performed monocularly. In total, 20 healthy volunteers with no accommodation problems or colour blindness were included.Results: On average, the accommodative response with no filter condition was larger compared to the measurements with filters for 40 and 100 cm. The differences were in all cases lower than 0.25D, and differences were not statistically significant (p > 0.05). For the colour discrimination thresholds, the ML41 and 511 filters showed statistically significant different values compared to the other two conditions for most of the vectors. The filter 511 had the highest impact on the colour vision, as the results resemble to a Tritan defect.Conclusions: The accommodative response in healthy young adults was not significantly different than the no filter condition. The colour discrimination thresholds with the filter ML41 and 511 were significantly different compared to the no filter condition.