Comparison Between Age-Corrected Normative Threshold Values for the Static Stimulus Sizes Goldmann III and V, Assessed With a New Fast Thresholding Estimation (GATE)

Abstract

Purpose: : To assess the differences of the age-corrected normative differential luminance sensitivity (DLS) values for automated static perimetry with Goldmann stimulus size III and V using GATE (German Adaptive Threshold Estimation).

Methods: : Sixty-six normal subjects (10 to 79 years) were examined with the Octopus 900 perimeter. The grid of 86 test locations up to 80 degrees was condensed towards the center of the visual field. Static stimuli of Goldmann size III and size V were presented during two sessions on a photopic background (10 cd/m²). The fast thresholding algorithm GATE was used with an initial step size of 4 dB and at least one reversal. DLS values were estimated by applying the maximum likelihood (ML) procedure. Two smooth mathematical models were fitted separately to the two data sets, in order to predict the local DLS values for any location of the entire visual field.

Results: : The difference between the predicted DLS values (V-III) was calculated to assess the differential shape of the fitted models. This difference varied depending on the age from +3 dB to +5 dB in the center, showed an interaction between age and eccentricity outside the center, and in the periphery ranged from +8 dB to +11 dB.

Conclusions: : A smooth mathematical model allows the estimation of the differences in measuring the normative local DLS thresholds. For normal subjects a DLS difference (V-III) of approximately +3 dB to +5 dB can be observed in the centre of the visual field. The DLS difference was greatest in the periphery, decreases with the age for low eccentricity values, and increases with age for high eccentricity values.

Clinical Trial: : IRB Tuebingen, 217/2006

Keywords: perimetry • visual fields • nerve fiber layer