Purpose: Objective pupilloperimetry in healthy subjects and patients with Best’s Vitelliform Macular Dystrophy using a chromatic multifocal pupillometer (CMP).
Methods: A CMP (Accutome Inc) was used to record pupillary responses (PR) of 17 healthy subjects and 5 Best’s patients. Red and blue light stimuli were presented at 76 locations of a 16.2 degree VF. The PR of patients were compared with their findings on Humphrey's 24-2 perimetry, Optical Coherence Tomography (OCT) and with the PR of healthy subjects. Percentage of Pupil Constriction (PPC), maximal constriction velocity (MCV) and the latency of MCV (LMCV) were determined.
Results: In response to red light, Best’s patients demonstrated reduced PPC and slower MCV compared with healthy subjects in nearly all test point locations. Severity of defects in PPC in responses to red light correlated with reduced thickness of photoreceptor layer as determined by OCT in the central, superior, nasal and temporal areas of the central retina (Pearson's r= -0.93, -0.91, -0.92, -0.85, respectively). By contrast, in response to blue light stimuli, the PPC and MCV of patients were lower than normal only in several central points. Surprisingly, the latency of MCV was shorter in patients compared with healthy subjects in response to red and blue stimuli.
Conclusions: This study demonstrates the potential feasibility of using pupillometer-based chromatic perimetry for objectively assessing VF defects in patients with Best’s macular dystrophy. Our findings also suggest that chromatic pupilloperimetry may differentiate between PR mediated by cones or rods, and can specifically detect defects in macular cones.