[Effect of induced refractive errors on measurement of color vision by using D15 test]

To evaluate the effect of Hyperopia, Myopia and Astigmatism on measurement of color vision, we experimentally induced refractive errors by positive, negative and cylinder lenses and estimated this effect on measurement of color vision. From one hundred patients referred to optometry clinic, sixty subjects with distance corrected or uncorrected visual acuity of 6.6, and without any ocular pathology were selected. Color vision was measured by D15 test before and after introducing 2 to 14 diopter positive lenses, 4 to18 diopter minus lenses and 2 to 10 diopter positive cylinder lenses, to induce Hyperopia, myopia and astigmatism respectively. The age was between 15 to 45 years. Although the decrease in color vision [or increase in the mean errors] was significant by introducing 4 to 14 positive, 8 to 18 minus and 4 to 10 cylinder, but it was not statistically significant by introducing 3 D positive lenses, 3D cylinder lenses and 4 D minus lenses. Induced 4 D or more myopia and astigmatism reduces color vision measured by D-15 test. But induced 8D or more Hyperopia can cause reduction in color vision measurement? On the other hand myopia and astigmatism less than 4 diopters, and hyperopia less than 8 diopters have no effect on the measurement of color vision