Blue light-filtering intraocular lenses and scotopic sensitivity.

摘要

In their study of the pupil diameter of Japanese individuals as a function of age,1 Nakamura et al. measured 140 eyes of 70 subjects 19 to 80 years of age using an infrared open-view pupillometer (ie, a device that does not obstruct the eye not being measured) at distance and near fixation under 5 lux and 500 lux ambient illumination. They found the mean pupil diameter as a function of age to be consistently smaller than values reported in the literature, and they speculate that this may be due to their unique subject cohort. There are simpler explanations. First, the low-light pupil diameter measurement was at 5 lux, whereas most investigators attempting to simulate night-driving conditions use 1 lux or less.2'3 At 5 lux, there is enough foveal cone activity that small high-contrast print such as that found in a medical journal can be read fairly easily (Jay Bradley, MD, personal communication, May 2009).