Abstract
Purpose: :
The purpose of this study was to compare the performance of the AdaptRx (Apeliotus Vision Science, Atlanta, GA) with the Goldmann-Weekers Adaptometer (Haag-Streit, Koniz, Switzerland). The AdaptRx is intended for use as a clinical research tool. The design incorporates features aimed at simplifying operation, reducing patient burden and improving data interpretation. In particular, the AdaptRx utilizes a novel parameter called the rod intercept to provide a uniform, objective estimate of dark adaptation speed across a broad range of physiological responses. It is useful to know whether measurements with the AdaptRx are equivalent to measurements with the traditional Goldmann-Weekers Adaptometer.
Methods: :
The criterion for determining equivalence was whether dark adaptation speed as measured by both devices was correlated. The study sample consisted of 12 participants with a range of eye health status, including 8 healthy volunteers, 2 participants with age-related macular degeneration (AMD) and 1 participant with diabetic retinopathy (DR). Each participant’s dark adaptation was measured with both the AdaptRx and the Goldmann-Weekers. The order of testing was counter balanced between the participants. Dark adaptation speed was estimated using two parameters: the rod-cone break and the rod intercept. The rod-cone break is the time at which rods become more sensitive than cones and is characterized by the classic inflection point in the dark adaptation function. The rod intercept is the time at which visual sensitivity recovers to a criterion level (0.005 scotopic cd/m2).
Results: :
The relationship between dark adaptation speed as measured with both devices was tested by the Pearson correlation coefficient. Both the rod-cone break (r = 0.71, p = 0.0132) and the rod intercept (r = 0.75, p = 0.008) were highly correlated between the two instruments. Furthermore, the rod-cone break and rod intercept parameters were highly correlated with each other (r = 0.93, p < 0.0001 for the AdaptRx; r = 0.92, p < 0.0001 for the Goldmann-Weekers Adaptometer).
Conclusions: :
The performance of the AdaptRx is equivalent to the performance of the Goldmann-Weekers Adaptometer and the rod-cone break and rod intercept parameters provide equivalent estimates of dark adaptation speed. Thus, the AdaptRx is a practical tool for routine use in clinical studies.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: outcomes/complications