LOW-CONTRAST LETTER ACUITY IN AGE-RELATED MACULOPATHY

Distance low contrast letter acuity (LCLA) was assessed in six subject s with age-related maculopathy (ARM) and 12 subjects with normal visua l function using a series of eight Regan charts ranging in contrast fr om 4% to 96%. Mean logMAR acuities for letters of 96% contrast were -0 .205, -0.053 and 0.748 for the young control group (mean 23.3 years), the age-matched control group (mean 70.3 years) and the ARM subjects ( mean 72.3 years), respectively. The LCLA function was found to be sign ificantly better for the six in the young control group compared with the six age-matched controls (P < 0.05). The ARM subjects performed si gnificantly poorer (P < 0.05) at each contrast level down to 20% compa red with the age-matched subjects. A constant 0.8 logMAR difference wa s found between the LCLA function of the age-matched controls and that of the ARM subjects. These results show that, since the low contrast test charts revealed similar differences in visual acuity between the ARM and the age-matched groups, the use of low contrast letter charts do not appear to give any additional information of acuity loss. Copyr ight (C) 1996. The College of Optometrists.