Asymmetry and variation in the normal hill of vision.

This analysis describes the symmetry and variation in the shape and height of the "hill of vision" obtained from automated static visual field testing of 146 normal eyes of 81 people aged 20 to 78 years. Threshold values dropped from the center to the 30 degrees periphery, with the greatest decrease occurring in the superior quadrant. Variability also increased with distance from the center of fixation, with the greatest variability occurring in the superior quadrant. Threshold values were lower throughout the field in individuals over age 60 years compared with those who were younger, with the greatest decrease in thresholds occurring in the superior quadrant. This age effect was not explained by differences in pupil diameter or central acuity. Variability was higher in the older group, but only in the periphery (greater than 24 degrees from fixation).