Abstract
Purpose: To determine and compare age-related changes in amplitude and latency of the impulse response function derived from the multifocal electroretinogram (mfERG) (IRFe) and from psychophysical experiments (IRFp).
Methods: Single flash IRFe were derived from the binary kernel series of mfERG recordings in 70 normal subjects (ages 9 to 80 years) using synthesis analysis (VERIS ScienceTM 5.0). Response density |N1| +P1 and implicit time N1 and P1 were analyzed for the area 5 to 10 deg in radius. For the same area, IRFp were collected from 75 normal subjects (ages 16 to 86) using a double-pulse method with a Gaussian patch (+/− 1SD = 2.3 deg) presented in one of four quadrants defined by a central fixation cross, and analyzed for the peak amplitude and the duration of the first phase.
Results: The IRFe to a single flash showed a significant age-related decrease in response density and a significant increase in latency N1 but not in latency P1. The response density showed greater fractional changes with age than implicit time. The IRFp revealed a significant reduction in amplitude and little change in speed with age.
Conclusion: Age-related changes of the retinal IRF parallel those of the psychophysical IRF. There are significant reductions in amplitude (response density) with age. The speed of the retinal IRF decreases rather slightly with age. These results imply that much of the senescent change in temporal vision can be explained by age-related changes at a retinal level.