Age-related macular degeneration is a sight-threatening disease that typically affects older Americans; this condition is the leading cause of decreased vision in people over 60, according to the National Eye Institute. Some therapies for the disease exist such as laser and ocular injections, but these therapies do not cure the condition and may not help improve visual acuity. Researchers have been evaluating additional treatment options that may delay or prevent the condition; one hormone called melatonin has shown some benefit in the prevention of macular degeneration.
What Is Melatonin?
Melatonin is a hormone that is produced in the brains of humans, according to MayoClinic.com. This hormone is thought to have a role in the control of your sleep-wake cycle; melatonin production increases in the presence of darkness and decreases with more light. Higher levels of the hormone are present right before bedtime. It has been used as a sleep supplement and has significant antioxidant activity.
Melatonin and Macular Degeneration
Early research showed that higher concentrations of melatonin could elevate the amount of pigment in the retina, which is the light-sensitive tissue in the back of the eye that processes vision. The pigment protects cells in the retina from strong light. As you get older, the level of melatonin in the body decreases; this may increase the risk of damage to the retina because less pigment is present due to decreased hormone. An article published in the "Annals of the New York Academy of Sciences" in 2005 showed that supplementation of 3mg of the hormone at bedtime stabilized the vision of participants with macular degeneration. The researchers also found that the majority of the retinas also showed less evidence of the disease; the authors suggested that melatonin protected the retina and delayed the progression of macular degeneration. Further study is needed to demonstrate this benefit.
Melatonin and Repair in Macular Degeneration
Another study that evaluated the effect of melatonin on age-related macular degeneration was published in late 2010 in the journal "Medical Hypotheses" by Reza Rastmanesh. This author suggests that melatonin can improve the ability of the cells in the retina to repair themselves after various types of damage; it may also reduce the presence of vascular endothelial growth factor and nitric oxide--both of which promote the destructive changes that occur in macular degeneration in the eye. Rastmanesh suggests that health care providers prescribe melatonin supplementation for older people who have low levels of melatonin or who may be at high risk for the disease. Additional research to support his conclusions is also needed.
Warnings
Taking additional melatonin as a supplement may cause vivid dreams and nightmares in some people, as noted by the University of Maryland Medical Center. It may also cause sleep schedule disruptions or cause drowsiness if taken earlier in the day. Melatonin may cause stomach upset, impaired fertility, enlarged breasts in men, dizziness and headaches. The use of melatonin to prevent macular degeneration is still in the early stages because the evidence to fully support this indication does not exist. As with all supplements, you should discuss your thoughts and interest in using this treatment with your physician. Your physician may want to monitor your melatonin levels to make sure they remain within normal limits.
