Influences of accommodation and myopia on the foveal Stiles-Crawford effect
نویسندگان
چکیده
We determined the foveal Stiles-Crawford Effect as a function of up to 8 D accommodation stimulus in 6 young emmetropes and 6 young myopes using a psychophysical two-channel Maxwellian system in which the threshold luminance increment of a 1mm spot entering through variable positions in the pupil was determined against a background formed by a 4 mm spot entering the pupil centrally. The SCE became steeper in both groups with increasing accommodation stimulus, but with no systematic shift of the peak. Combining the data of both groups gave significant increases in directionality of 15-20 % in horizontal and vertical pupil meridians with 6 D of accommodation. However, additional experiments indicated that much of this was an artefact of higher order aberrations and accommodative lag. Thus, there appears to be little changes in orientation or directionality in the SCE with accommodation stimulus levels up to 6 D, but it is possible that changes may occur at very high accommodation levels.
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