Abstract
Abstract: :
Purpose: To study the dynamic visual field characteristics in age–related maculopathy (ARM) we measured motion sensitivity, double–pulse resolution (DPR) and critical flicker fusion in 14 AMD patients (18 eyes), age–matched controls, and young controls. Methods: Motion stimulus was a plaid with spatial and temporal Gaussian envelope, moving in one of four directions at constant velocity (5.7°/s) inside the Gaussian aperture. Motion contrast thresholds were determined by a 4–afc staircase algorithm (Kesten, modified after Kaernbach, 2001) on the horizontal meridian at 10°, 20°, 30°, 40°, and 60° eccentricity. DPR was measured under photopic conditions using Treutwein's 9–fold interleaved technique (Treutwein, 1991) with stimuli positioned on concentric rings at 5°, 10°, and 20° eccentricity, with stimuli on the main and oblique meridians, at a total of 25 positions. CFF was measured only foveally. Results: In both control groups, motion contrast sensitivity systematically declined with retinal eccentricity (0.009 – 0.032 log units/deg) and slightly with age (0.01 log units/year). Motion contrast sensitivity in the age–matched ARM group was pronouncedly reduced (0.23 – 0.66 log units, p< 0.01), not only in the macula but out to at least 20° eccentricity. Photopic double–pulse thresholds in normals were approximately constant in the central visual field and increased outside a radius of 10° (1.73 ms/deg). DPR thresholds were strongly increased in ARM patients (by 23 –32 ms, p< 0.01) in the entire test field up to 20° eccentricity, which confirms the findings from motion sensitivity. The foveal CFF was increased in ARM by 5.5 Hz (14%, p< 0.01). Conclusions: Dynamic processing properties in ARM patients are severely impaired in the central visual field of at least 20° radius, which is clearly beyond the borders of the macula. This difference cannot be explained by a difference in age.
Keywords: age–related macular degeneration • motion–2D • contrast sensitivity