Multifocal Pupillography in Early Age-Related Macular Degeneration

Purpose. To investigate the potential of multifocal pupillographic objective perimetry to assess changes in retinal function with clinical severity of age-related macular degeneration (AMD). Methods. Pupil responses were recorded from 40 subjects with AMD and 23 normal control subjects (mean +/- SD age, 71.3 +/- 5.1 years). Age-related macular degeneration subjects were classified according to the Age-Related Eye Disease Study (AREDS) classification system and allocated into one of four AMD severity groups. Three multifocal pupillographic objective perimetry stimulus variants that were identical in luminance but varied in spatiotemporal sequence were used. In one of the three protocols, stimuli were presented with a pedestal flicker for 266 milliseconds at 15 Hz. Results. On average, response amplitudes demonstrated a significant change in sensitivity with progression from early-stage (0.32 +/- 0.08 dB, t = 3.88) to late-stage (-1.60 +/- 0.12 dB, t = -12.7) age-related macular degeneration. Response delays followed a similar trend with the longest delays in AREDS4 (57.2 +/- 1.9 milliseconds, t = 29.5). Ring analysis identified the largest mean effect on responses within the central 6 degrees of fixation. The NewStimuli protocol achieved the best diagnostic accuracy across all severity groups with area under the curve values of 0.85 +/- 0.066 (AREDS1), 0.908 +/- 0.085 (AREDS2), 0.929 +/- 0.040 (AREDS3), and 1.0 +/- 0.0 (AREDS4). Conclusions. The mean effect of AMD on contraction amplitudes and response delays reflected the severity of disease, and the NewStimuli protocol achieved good diagnostic accuracy across all AMD severity groups. Multifocal pupillographic objective perimetry may potentially be a useful method in monitoring progression of AMD and assessing change in retinal function with novel interventions in early AMD. Longitudinal studies are required to identify biomarkers that predict eyes at risk of progression.