This experiment investigated the following research question: Is pupil diameter affected by the eye color of the subject? It was found that eye color does affect pupil size. The experimental findings generally were not consistent with reports in the literature related to pupil size and eye color.
The Effects of Eye Color on Pupil Size
Hillis (1995, pp. 457-478) reported that both cognitive and neural mechanisms affect visual processing. Murphy (1991, pp. 161-192) reported that the effect of eye color on visual processing declines with age.
All lenses, including glass and natural lenses, bring different color light into focus at slightly different points (Fowler, 1991, pp. 1109-1110). In the eye, sharpness is largely a function of cone cells. Cone cells exist in red-, green- and blue-sensitive types. The blue-sensitive cone cells generally produce less sharp vision than do the red- and green-sensitive cone cells.
Veraart, et al. (1992, pp. 424-428) reported that stray light values for normal pupil size (mean, 4 mm) are statistically significantly higher (P = .0044) only for the smallest angle of light deflection studied (3.5 degrees). For dilated pupils (mean, 8 mm), stray light values were statistically significantly higher (P= .00005) for all three angles of light deflection studied. The number of incisions showed no statistically significant relationship to stray light values. Average stray light values were increased by a factor of 1.4 for 4-mm sized pupils and 2.0 for 8-mm sized pupils. There was an overlap in stray light values between the patient population and the control population.
Veraart, et al. (1992, pp. 424-428) reported further that great differences occur in stray light values among normal individuals. Among young people the differences generally relate to differences of eye coloration (van den Berg, et al., 1991, p. 1361).
The experiment, the results of which are presented in this report,...