A study is made of the relationship between dark adaptation and age. To describe one family of dark adaptation curves from an age sample of 240 men, ranging from 16 through 89 years, a mathematical model was derived. It was determined that age is highly correlated with all dark adaptation thresholds which in turn are highly intercorrelated. The correlation between age and dark adaptation thresholds tends to increase as time in the dark increases. Cone and rod thresholds are highly correlated, and the reduction in the threshold and rate of dark adaptation in relation to age is very marked. It was also demonstrated that a short clinical test of dark adaptation was entirely possible because thresholds obtained during the first few minutes of adaptation predicted dark adaptation sensitivity remote in time.
Abstract