January 28, 2023 - EyeClarity Blog
Melatonin is a hormone produced by the pineal gland in the brain that helps regulate the Body’s sleep-wake cycle. It is also present in the eye’s retina, regulating the cells’ circadian rhythm and protecting the retina from damage caused by light exposure. Studies have shown that Melatonin can act as an antioxidant in the retina, helping to protect against damage from free radicals and inflammation. Additionally, Melatonin protects against retinal degeneration, such as age-related macular degeneration.
The retina, the light-sensitive layer of eye tissue, contains Melatonin receptors. These receptors may play a role in regulating the retina’s circadian rhythm and protecting the retina. Melatonin may also have a protective effect on the retina by reducing inflammation and oxidative stress.
Other studies have also shown that Melatonin may help to improve the function of the blood vessels in the retina, which can be beneficial for people with conditions such as diabetic Retinopathy. Additionally, Melatonin demonstrates neuroprotective effects on the retina, which may be helpful for people with age-related macular degeneration (AMD).
The retina, the light-sensitive layer of eye tissue, contains Melatonin receptors. These receptors may play a role in regulating the retina’s circadian rhythm and protecting the retina. Research has suggested that Melatonin may protect the retina by reducing inflammation and oxidative stress.
Other studies have also shown that Melatonin may help to improve the function of the blood vessels in the retina, which can be beneficial for people with conditions such as diabetic Retinopathy. Additionally, Melatonin has neuroprotective effects on the retina, which may be helpful for people with age-related macular degeneration (AMD).
Let’s get into the specifics.
According to a series of research studies, researchers reported that the combination of Melatonin, selenium, and zinc before you go to sleep helps neutralize macular degeneration. The studies reported some improvement by taking this combination for six months. [1],[2]
Researchers found a connection between macular degeneration and reduced mitochondria function in another report. Increasing Melatonin, one of the effects was that the mitochondria worked better, reducing inflammation and oxidative stress in the retina. [3]
Glaucoma
Melatonin levels in the Body are highest at night and lowest during the day. The eye pressure (referred to as intraocular pressure) is also lowest at night and highest during the day.
The eye has a structure called the Ciliary Body that produces fluid in the aqueous humor. According to a paper published in Current Eye Research, there may be a relationship between supplementing with Melatonin to bring down your eye pressure. Here is how it works.
This Ciliary Body has receptors activated by Melatonin. [4] The more Melatonin, the better the ciliary body functions, and the more aqueous flow can happen, lowering eye pressure.
In another study, researchers have found that Melatonin may also help improve circadian rhythms and sleep for people with advanced glaucoma. [5]
Night Vision
Another research discovery is the relationship between Melatonin and Glutathione. Researchers found that increasing Melatonin helped increase glutathione in the Body. [6] One of the less-known benefits of glutathione is that it can improve night vision.
Melatonin helps some other eye conditions: Uveitis [7]
(inflammation in the inside part of the eye) Diabetic Retinopathy [8], and Optic Neuritis (swelling of the optic nerve).
Can we get Melatonin from foods?
Here are foods containing Melatonin: cherries, cage-free organic eggs, grapes, walnuts, strawberries, bananas, barley, lentils, mushrooms, green beans, coffee, sprouted soybeans, tomatoes, and oats. And can also be taken as a dietary supplement.
Blue Light and Melatonin.
Blue Light exposure can also affect melatonin production. In the evening, when light levels decrease, melatonin production increases, which can help regulate sleep. However, exposure to artificial blue light after 6:00 pm inhibits Melatonin production, which affects sleep.
Melanopsin and the Retina
The retina contains cells called rods and cones, which detect light. These cells also have a protein called Melanopsin, which responds to light and helps regulate Melatonin production. Specifically, Melanopsin in the retina cells helps to detect light and send signals to the brain’s suprachiasmatic nucleus (SCN), which controls the production of Melatonin. In response to the presence of light, the SCN signals the pineal gland to reduce the production of Melatonin, making us feel more alert. In contrast, in response to darkness, the SCN signals the pineal gland to increase Melatonin’s output, making us feel sleepier.
Melanopsin plays a critical role in regulating the Body’s response to light and dark and helps to synchronize the internal clock with the external environment. Melanopsin is in cells called intrinsically photosensitive retinal ganglion cells (ipRGCs) in the eye. These cells are responsible for detecting light and sending signals to the brain that help regulate the Body’s circadian rhythm or internal “biological clock.” Blue light from the sun activates Melanopsin. It helps to regulate the sleep-wake cycle and other physiological processes, such as pupil constriction and suppression of melatonin secretion.
These Retinal Ganglion Cells (Melanopsin) have photoreceptors built inside their cells. Even if you have low and no vision, if you have retinas, you still have these RGC cells. These cells communicate to areas of the brain based on the quality of light conditions and signals to the brain. Is it early or late in the day? These cells behave like photoreceptors. The regulations are necessary because they will tell you about being sleepy, awake, blood sugar levels, dopamine levels, metabolism, and pain threshold. They are the most potent determinants. [9] These photoreceptors help balance the blue and yellow light—when you view the sun in the AM and PM.
Here is a practice you can do to help you increase your mood, dopamine, alertness, and vision: view the sunlight even through cloud cover for 2-10 minutes while low in the sky—in the AM and late in the day. If you don’t get daily sun exposure, you are severely disrupting your mood, sleep rhythms, hormones, metabolism, pain threshold, and ability to learn and remember information. Get light in your eyes early in the day as much as possible while being safe to remain alert. The blue light and the blue-yellow contrast—we don’t see blue reflections—are subconscious, based on considerations of the sun. This blue light wakes up the brain. Viewing early in the day is recommended. The visual system has ancient cells to inform your Body and brain about the time of day. If we live in an overcast environment, getting an artificial light box that emits blue is beneficial. It contrasts with yellow, which triggers the melanopsin cells, circadian rhythm, and every cell in your Body. Bottom line; get Bright light in the eyes for 2-10 minutes without sunglasses. It is essential for your biology and psychology.
[1] Stefanova NA, ZHdankina AA, Fursova AZ, Kolosova NG. (2013). Potential of Melatonin for prevention of age-related macular degeneration: an experimental study. Adv Gerontol. 26(1):122-9.
[2] Yi C, Pan X, Yan H, Guo M, Pierpaoli W. (2005). Effects of Melatonin in age-related macular degeneration. Ann N Y Acad Sci. Dec;1057:384-92
[3] Mehrzadi S, Hemati K, Reiter RJ, Hosseinzadeh A. (2020). Mitochondrial dysfunction in age-related
macular degeneration: Melatonin as a potential treatment. Ther Targets. Apr;24(4):359-378. ↩
[4] Alkozi HA, Navarro G, Franco R, Pintor J. (2020). Melatonin and the control of intraocular pressure. Prog Retin Eye Res. Mar;75:100798. ↩
[5] Gubin D, Neroev V, Malishevskaya T, Cornelissen G, Astakhov SY, et al. (2021). Melatonin mitigates disrupted circadian rhythms, lowers intraocular pressure, and improves retinal ganglion cells function in glaucoma. J Pineal Res.May;70(4):e12730
[6] Abe M, Reiter RJ, Orhii PB, Hara M, Poegeler B. (1994). Inhibitory effect of Melatonin on cataract formation in newborn rats: evidence for an antioxidative role for Melatonin. J Pineal Res, Sep;17(2):94-100. ↩
[7] Rosenstein RE, Pandi-Perumal SR, Srinivasan V, Spence DW, Brown GM, et al. (2010). Melatonin as a therapeutic tool in ophthalmology: implications for glaucoma and uveitis. J Pineal Res. Aug;49(1):1-13. ↩
[8] Scuderi L, Davinelli S, Iodice CM, Bartollino S, Scapagnini G, et al. (2019). Melatonin: Implications for Ocular Disease and Therapeutic Potential.
Curr Pharm Des. 2019;25(39):4185-4191. ↩
[9] https://pubmed.ncbi.nlm.nih.gov/11834834/