Abstract
Purpose :
To evaluate the ability of handheld chromatic pupillometry (HCP) to characterise and evaluate functional loss in patients with inherited retinal dystrophies (IRD).
Methods :
In a cross-sectional study, we included 47 patients with IRD and 26 age-matched controls (44.5 ± 14.2 years, 53.8% males). The IRD population included 27 patients with rod-cone dystrophies (RCD, 50.7 ± 16.9 years, 55.6% males) and 20 patients with cone or cone-rod dystrophies (CRD, 53.8 ± 15.8 years, 50% males). Prior to an extensive ophthalmic examination that included electroretinography, participants underwent monocular evaluation of the pupillary response to 9 seconds of ramping-up blue (469nm) and red (640nm) light stimuli (45° field, 12.5-14 log photons/cm2/s). Pupillary light responses (PLRs) were assessed using a custom-built handheld pupillometer. Baseline-adjusted pupillary constriction traces were calculated for each participant and pupillometric features were extracted and compared between groups using a one-way ANOVA followed by a Holm-Sidak pairwise comparison.
Results :
PLRs were altered in IRD patients (Fig. 1) who displayed a reduction in phasic constriction to blue and red lights compared to controls (P<0.05). RCD patients showed a greater reduction in the phasic constriction to blue light compared to CRD patients (P=0.03). Maximum constrictions to both lights were also reduced in IRD groups compared to controls. The early pupil redilation slope, calculated within 1.7s from blue light offset, an indicator of outer retinal contribution to the predominantly melanopsin-driven post-illumination pupillary response (PIPR), was decreased in IRD patients compared to controls (P<0.001). Consequently, the Net PIPR (blue PIPR - red PIPR) was increased in IRD patients, yet, this increase was not statistically significant (P=0.09) (Fig. 2).
Conclusions :
Pupillometric features mainly driven by rods and cones (e.g., phasic constriction, early redilation slope) are altered in IRD patients. HCP can identify outer-retinal dysfunction and may provide a rapid method for detecting eyes with IRD.
This is a 2021 ARVO Annual Meeting abstract.