title: Measurement of temporal summation of visual acuity with use of modified tachistoscope.
abstract: Visual acuity was measured in 18 normal eyes of 10 subjects ranging in age from 20 to 30 years, using a modified tachistoscope. We changed the exposure duration of the target (1-1000 msec) or background luminance (0.1-200 cd/m2). Visual acuity improved with increasing duration of exposure. At background luminance over 10 cd/m2, critical duration time was approximately 500 msec. At low luminances below 10 cd/m2, however, critical duration was prolonged. This tendency was also seen when pupil diameter was fixed at 3 mm using an artificial pupil. Visual acuity also could be determined as the product of background luminance and exposure duration. We concluded that these findings follow the Bloch-Bunsen-Roscoe law.
authors.affiliation: Department of Ophthalmology, Tokyo Medical and Dental University, School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Niwa
authors.forename: T
authors.initials: T
authors.lastname: Tokoro
mesh_terms: D000328:Adult; D006801:Humans; D008027:Light; D011680:Pupil / Q000502:physiology; D014787:Vision Tests / Q000295:instrumentation*; D014792:Visual Acuity / Q000502:physiology*