The effect of cataract surgery on salivary melatonin and sleep quality in aging people

Abstract

Blue light plays an important role in circadian photoentrainment by stimulating the melanopsin-expressing photosensitive retinal ganglion cells. Age-related cataract causes progressive loss of blue light transmission, which may lead to changes in circadian rhythm and sleep quality. In theory, increased light transmission by cataract surgery may improve circadian misalignment and sleep quality, while the effect of cataract surgery on circadian rhythm is not well understood. In this study, we assessed 30 binocular age-related nuclear cataract patients (aged 72.5 ± 7.2, 16 female) who were eligible for cataract surgery. All the patients underwent phacoemulsification cataract extraction and neutral ultraviolet-only blocking intraocular lens (IOLs) implantation. Visual functions including best-corrected visual acuity (BCVA), color perception and dark adaptation were assessed. Salivary samples were collected at 1-hour interval from 19:00 to 23:00 48 hours before and after surgery. Salivary melatonin concentration was measured and dim light melatonin onset (DLMO) was calculated subsequently. Sleep quality and daytime alertness were assessed before and a month after surgery using Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). All the operated eyes demonstrated significant improvements in BCVA, color perception and dark adaptation after cataract surgery. Salivary melatonin concentration at 23:00 was significantly increased after surgery (P < 0.001). However, the average DLMO did not change significantly after surgery. In addition, PSQI and ESS scores were significantly decreased a month after surgery (P = 0.027, P < 0.001, respectively). In conclusion, cataract surgery promotes blue-light transmission; consequently, it may lead to the increase in nighttime melatonin concentration and improvement in sleep quality as well as daytime alertness.

Looking for light in the din: An examination of the circadian-disrupting properties of a medical intensive care unit

“…Morning (7am–12pm) light levels averaged only 12.1 (4.8, 37.2) lux in our study, well below the intensity of a well-lit office (300–500 lux), much less a sunny day (50,000 lux). Such light levels are highly likely to be inadequate, particularly in patients with cataracts (Shenshen et al 2016). Furthermore, critically ill patients’ eyes are often closed during the daytime due to sedation, encephalopathy, or sleep-wake dysregulation, reducing circadian-effective light transmittance by two orders of magnitude (Bierman et al 2011).…”

Plasticity in the Sensitivity to Light in Aging: Decreased Non-visual Impact of Light on Cognitive Brain Activity in Older Individuals but No Impact of Lens Replacement

“…Lens replacement has been reported to improve visual acuity, color perception, and dark adaptation ( Shenshen et al, 2016 ). Interestingly, inconsistent effects on sleep and circadian characteristics have been reported.…”

Abnormal environmental light exposure in the intensive care environment

“…Increasing daytime light can normalize circadian rhythm timing and has been show to increase normal nocturnal melatonin secretion with resulting improvements in circadian modulated physiologic parameters in both translational and human studies. [11–13]…”