Influence of Circadian Rhythm in the Eye: Significance of Melatonin in Glaucoma

Abstract

Circadian rhythm and the molecules involved in it, such as melanopsin and melatonin, play an important role in the eye to regulate the homeostasis and even to treat some ocular conditions. As a result, many ocular pathologies like dry eye, corneal wound healing, cataracts, myopia, retinal diseases, and glaucoma are affected by this cycle. This review will summarize the current scientific literature about the influence of circadian patterns on the eye, focusing on its relationship with increased intraocular pressure (IOP) fluctuations and glaucoma. Regarding treatments, two ways should be studied: the first one, to analyze if some treatments could improve their effect on the ocular disease when their posology is established in function of circadian patterns, and the second one, to evaluate new drugs to treat eye pathologies related to the circadian rhythm, as it has been stated with melatonin or its analogs, that not only could be used as the main treatment but as coadjutant, improving the circadian pattern or its antioxidant and antiangiogenic properties.

The Clock:cycle complex is a major transcriptional regulator ofDrosophilaphotoreceptors that protects the eye from retinal degeneration and oxidative stress

“…CC-BY-NC-ND 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made contributes to glaucoma and is also implicated in development of myopia (71,72). We note that while preparing this manuscript, a preprint showed that expression of CLK DN under the photoreceptor-specific trpl-Gal4 driver caused decreased phototactic behavior in young flies relative to an age-matched control (73), which is consistent with the rhabdomere loss observed in our study.…”

“…Since the PER::LUCIFERASE fusion protein is wild type and is used as a model for studying circadian rhythms (70), this observation suggests that even very mild changes in the expression or function of core circadian clock regulators can negatively impact the health of the aging eye. Notably, disruption of circadian rhythms in the human eye contributes to glaucoma and is also implicated in development of myopia (71,72). We note that while preparing this manuscript, a preprint showed that expression of CLK DN under the photoreceptor-specific trpl-Gal4 driver caused decreased phototactic behavior in young flies relative to an age-matched control (73), which is consistent with the rhabdomere loss observed in our study.…”

Ocular Complications of Obstructive Sleep Apnea

“…The precise etiological mechanisms underlying OSA-mediated glaucoma remain unclear, but there are several possible explanations. One theory suggests “mechanical” damage due to nocturnal increased IOP from supine sleep posture, altered sleep hormone balance (a nocturnal serum melatonin peak, which is associated with lowered IOP during sleep, was absent in OSA patients), obesity with excessive intraorbital adipose tissue or increased episcleral venous pressure, and autonomic dysfunction [ 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ]. Another theory explores ischemia or abnormal perfusion as the cause of optic disc vulnerability leading to the observed normal IOP value [ 38 ].…”

Research progress of melatonin (MT) in improving ovarian function: a review of the current status

“…Giving exogenous MT at the same time of the day can trigger physiological and behavioral rhythms (such as body temperature and rest-activity cycles) [ 80 ]. According to previous reports, MT can regulate a variety of biological functions, including the vision, neuroendocrine, reproduction, neuroimmunity, and vascular physiology [ 13 , 81 – 84 ]. Since the MT secretion is proportional to the night length, MT also presents a regular seasonal change cycle.…”