The reading addition required by each of 30 subjects in this study was determined subjectively by means of five different cross-cylinder targets and under three photopic luminance levels of 3.5, 30, and 220 cd per m2. We conclude that the amount of the reading addition is not significantly affected by moderate changes in target configuration nor by changes in specific photopic luminance levels of either fluorescent or incandescent light.
Presented at the Annual Meeting of the American Academy of Optometry in Orlando, Florida, 1981.
Received September 15, 1981; revision received February 26, 1982.
† Optometrist, Ph.D., Member of Faculty, F.A.A.O.
George C. Woo
School of Optometry
University of Waterloo
Canada N2L 3G1
© 1982 American Academy of Optometry