Intrinsically photosensitive retinal ganglion cell activity is associated with decreased sleep quality in glaucoma patients

Abstract

Purpose: To evaluate the function of intrinsically photosensitive retinal ganglion cells (ipRGCs) using the pupillary light reflex and compared with polysomnography in glaucoma patients.

Methods: A cross-sectional study was conducted on both eyes of 45 participants (32 glaucoma patients and 13 healthy subjects). For the pupillary reflex evaluation, patients were tested in the dark using a Ganzfeld system for stimulation; pupil diameter was measured with an eye tracker system. To preferentially stimulate ipRGCs, we used a 1-second 470-nm flash with a luminance of 250 cd/m². To stimulate different retinal photoreceptors (cones and rods), we used a 1-second 630-nm flash with a luminance of 250 cd/m². All subjects underwent polysomnography. For ophthalmological assessments, all subjects underwent standard automated perimetry and optical coherence tomography (Cirrus HD-OCT).<br /> Correlations among ipRGC activity measured by the pupillary light reflex, polysomnography and retinal nerve fiber layer (RNFL) thickness were performed.

Results: The mean patient ages in the healthy and glaucoma groups were 56.8 ± 7.8 and 61.5 ± 11.6 years, respectively (p= 0.174). Glaucoma patients had a significantly lower average total sleep time, sleep efficiency and minimum oxyhemoglobin saturation compared to the healthy subjects (p = 0.008, p = 0.002 and p = 0.028, respectively). Additionally, glaucoma patients had significantly higher arousal durations after falling asleep and periodic limb movements (p = 0.002 and p = 0.045, respectively). There was a correlation between the REM latency and the peak of the pupillary response to the blue flash (p = 0.004). The total arousals were associated with the sustained blue flash response (p = 0.029). The RNFL thickness was associated with the peak and sustained response to the blue flash (p  < 0.001 for both comparisons); however, the RNFL thickness was only associated with the mean oxygen desaturation index for polysomnography parameters (p = 0.023).

Conclusions: This study demonstrates the decreased ipRGC function caused by glaucoma disease affects not only the pupillary response but also the sleep quality.