Multifocal Pupillographic Assessment of Age-Related Macular Degeneration

Abstract

Purpose. To investigate retinal function in subjects with unilateral exudative age-related macular degeneration (AMD) using multifocal pupillographic objective perimetry (mfPOP) and to assess the diagnostic accuracy of this technique. Methods. We tested each of 20 exudative AMD patients and 20 control subjects with 4 different mfPOP stimulus variants. Multifocal stimuli consisting of 24 or 44 independent stimulus regions per eye extending from fixation to 15° eccentricity were presented dichoptically. The aperiodic stimuli were presented at 1 or 4 s mean intervals. Video cameras recorded pupil responses under infrared illumination. Test duration consisted of 8 segments of 30 s. Stimuli were presented at a luminance of 250 cd/m and a background of 10 cd/m. Peak regional contraction amplitudes, time to peaks, and a linear combination of these were used to produce receiver operator characteristic (ROC) curves to measure the diagnostic accuracy of this method. Results. Mean constriction amplitudes of exudative AMD subjects were decreased by 0.77 ± 0.15 dB (p < 5 × 10). Stimulus ensembles with 44 regions and faster presentation rates produced the largest effect on response sizes (t = 3.63; p < 0.0002). When comparing the control eyes to exudative AMD eyes, the area under the curve of ROC plots was 0.96 ± 0.03 (mean ± SE). This was achieved for asymmetry analysis of the difference in response amplitudes obtained from the two eyes at each point in the visual field. Conclusions. The mean effect of exudative AMD on contraction amplitudes reflected the severity of disease, and ROC analysis from amplitude deviations improved the sensitivity of detection of exudative AMD. A longitudinal investigation into the mfPOP responses of patients with non-exudative AMD may detect and classify visual fields with poor prognosis.