Chromatic Multifocal Pupillometer for Objective Perimetry and Diagnosis of Patients with Retinitis Pigmentosa

Effect of Stimulus Intensity and Visual Field Location on Rod- and Cone-Mediated Pupil Response to Focal Light Stimuli

“…The LMCV parameter was found to be relatively constant throughout the 16.28 visual field in healthy subjects. 18 High variability in LMCV between different VF locations was observed in RP patients, correlating with vision loss, and ROC analysis demonstrated the usefulness of this parameter for RP diagnosis with high specificity and sensitivity. 18 The present study was aimed at characterization of these three pupil response parameters at different light intensities at central and peripheral targets of a 248 VF for in depth characterization of the rod and cone photoreceptor mediated PLR in healthy subjects and as a model for future clinical testing of retinal and optic nerve pathologies.…”

“…A custom software was used to analyze the PLR parameters (Accutome, Inc., Malvern, PA, USA). 18 Automatically excluded were tests in which the subject blinked during the first 2.5 seconds (when the light stimulus was on and during the contraction phase of the PLR) and tests in which the pupil diameter was increasing during the first 0.45 seconds following light onset. These test points were retested.…”

“…1C). 18 To determine the variance in initial pupil diameter through the recordings, the differences between the initial pupil diameter measured during testing of the first test target in the first test run (target CNS, in response to red and blue light stimuli at 0.5 log cd/m 2 ) and the initial pupil diameter measured during testing of the first test target in the last test run (target CNS, blue light stimulus at 3.75 log cd/m 2 ) were determined for the 14 subjects tested under mesopic conditions. The mean initial pupil diameter measured in the first target tested in the last run in response to blue light (target CNS, blue light stimulus at 3.75 log cd/m 2 , mean [95% confidence interval]: 6.55 mm [5.97 mm-7.12 mm]) did not significantly differ from the initial pupil diameter measured in the first run of pupilloperimetry testing (the first test target in response to red light, target CNS, red light stimulus at 0.5 log cd/m 2 , mean [95% confidence interval]: 6.96 mm [6.27 mm-7.63 mm]).…”

“…5,[7][8][9][10][13][14][15][16] Recently, Park et al 17 characterized the PLR mediated by the different photoreceptor classes when using smaller stimulus sizes presented in the center of the visual field (VF) over a large range of light intensities. Chibel et al 18 provided evidence that the function of rods and cones at different locations in the central (16.28) VF can be assessed using smaller (Goldmann size III, 0.438) red and blue light stimuli at 1000 and 200 cd/m 2 , respectively, under mesopic (0.05 cd/m 2 uniform white light) adaptation. Thus, healthy participants showed higher percentage of pupil contraction (PPC) and maximal pupil contraction velocity (MCV) in response to red stimuli presented in central versus peripheral VF test points.…”

“…MCV was chosen for analysis as previous studies demonstrated that RP patients presented with a more pronounced defect in MCV than in PPC. 18 Furthermore, in a study comparing the pupillary response for white light stimuli presented either as a central 108 circular or a peripheral 30-60 degree annular stimulus, Ortube et al 19 demonstrated that the relative difference of the MCV between the central and peripheral stimuli was significantly lower in diabetic retinopathy patients compared with controls, suggesting that MCV may have a diagnostic potential for retinal pathologies. The LMCV parameter was found to be relatively constant throughout the 16.28 visual field in healthy subjects.…”