On the Stiles-Crawford effect with age.

ABSTRACT

PURPOSE: To determine whether the Stiles-Crawford effect remains stable after subjects have aged 30 years. METHODS: The relative luminous efficiency as a function of pupil position (Stiles-Crawford effect) was determined for the same seven subjects on the same apparatus in the 1960s and in 1995. The pupil opening was traversed nine times, at 20 degrees azimuth intervals. Data were fit with a revolution paraboloid yielding a peak position (x0, y0) and a peakedness (rho). RESULTS: Two of seven subjects showed a significant, but small, decrease in rho, and the other five showed, no change. No clear outcome in x0, y0 changes could be reported because of differences in pupil dilation then and now. CONCLUSIONS: Although exceptions are found on the stability of the Stiles-Crawford effect with age, the authors can still conclude that it is stable.