• Twenty-six normal eyes of 26 subjects were tested three times during an 18-month period using the 30-2 program of the Humphrey Visual Field Analyzer (Humphrey Instruments, San Leandro, Calif). For the average eye, the SD of threshold values over time ranged from 1.8 to 5.5 dB, depending on the location in the field. For those subjects under 60 years of age, SDs ranged from 1.2 to 2.8 dB. For those subjects 60 years of age and older, the range was 2.2 to 8.3 dB. Short-term fluctuations contributed 25% of the variability of threshold measurements over time. Short-term and long-term variations were greater in older eyes, but long-term variability was more affected by age than was short-term variation.
Katz J, Sommer A. A Longitudinal Study of the Age-Adjusted Variability of Automated Visual Fields. Arch Ophthalmol. 1987;105(8):1083-1086. doi:10.1001/archopht.1987.01060080085033