Abstract
Purpose :
Since the discovery of intrinsic photosensitive retinal ganglion cells (ipRGCs) and their influence on the pupillary light reflex (PLR), the importance of chromatic pupillometry (CP) as an independent method of examination has increased. Abnormal curve progressions of people suffering from glaucoma provide evidence of ipRGCs dysfunction or degeneration. The aim of this study was to evaluate different methods of analyzing chromatic pupillometry to becoming an established screening or monitoring method in glaucoma management.
Methods :
In a total 47 eyes of 31 glaucoma patients (mean age 71.5, SD ± 11.6 years) and 17 eyes of 11 controls (mean age 67.3, SD ± 12.8 years) were measured using monocular, direct chromatic pupillometry (Albomed PupilX-prototype, λred ≈ 643 nm, λblue ≈ 469 nm). Nine metrics were defined to quantify the CP results to assess the pupillary light reflex (PLR) and the Post Illumination Pupil Response (PIPR).
Results :
Regarding the PLR, constriction amplitudes were significantly reduced in glaucoma patients (pred = 0.001; pblue < 0.001). Within the early interval of the PIPR (0 - 10s) the curves in both groups showed significantly greater values for the enclosed areas (pControls < 0.001; pGlaucoma < 0.001) and stronger exponential gradients (pControls = 0.001; pGlaucoma = 0.025). Comparing the integrals in the late interval of the PIPR (10 - 28s) between the two groups, the controls displayed a significantly larger “blue” area under the curve (pred = 0.826; pblue = 0.007).
Conclusions :
The evaluated metrics and methods used to analyze chromatic pupillometry were able to demonstrate the pathological state of the patient’s ipRGCs. The outcomes provide evidence for the suitability of chromatic pupillometry as an objective, non-invasive method of examination.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.