Uveitis is a sudden inflammation of the eye that can cause blindness in 10 to 15% of cases. Research now suggests that melatonin can successfully treat the inflammatory changes that occur with uveitis, and protect the eye from damage. The findings on melantonin and Uveitis treatment appear in the December 2008 issue of The American Journal of Pathology.
Uveitis can be caused by several factors. The uvea is an important structure, as it supplies most of the blood to retina of the eye. It lies between the sclera and retina. Uveitis most commonly occurs in the front part of the eye. The condition is associated with rheumatoid arthritis but can result following exposure to toxins or as the result of eye injury. Other autoimmune diseases can also cause uveitis, such as multiple sclerosis, Grave's disease and systemic lupus erythematosis. HIV, herpes, sarcoidosis, toxoplasmosis and ulcerative colitis have also been associated with uveitis.
A common treatment is steroids, which can have unwanted side effects. Steroids that have to be used long-term can cause glaucoma. Middle age and young people are most commonly affected. There might be no underlying disorder. Uveitis might affect only one eye.
If uveitis occurs in the back of the eye, it can cause scarring that leads to blindness. Systemic infections can induce posterior uveitis, a condition known as chorioiditis. If the retina is also involved, the condition is called chorioretinitis.
Symptoms of uveitis include pain in the eye, redness, sensitivity to light and the presence of dark spots that float, causing blurring of vision. An eye exam, combined with a physical exam to rule out systemic causes should be performed if you develop symptoms. The condition is more serious when it involves the back of the eye (chorioiditis or chorioretinitis). The underlying cause must be diagnosed and treated.
If the front of the eye is affected (anterior uveitis), the condition often resolves in several days. Choroiditis or chorioretinitis may take weeks to months to resolve. Relapses are common, and treatment can be difficult.
Melatonin was used in the current study in animal models. Uveitis was induced with a single injection of bacterial lipopolysaccharide (LPS). The researchers implanted a pellet of melatonin into the eye of hamsters. They found a reduction of all markers of inflammation, up to 8 days following the injection. Melatonin protected retinal function, decreased clinical symptoms and protected the blood/ocular barrier of the eye, preserving blood supply.
The study authors conclude their research should be used to "support the use of melatonin as a new therapeutic strategy for the treatment of uveitis". The research was lead by Dr. Ruth Rosenstein of The University of Buenos Aires and The National Research Council (CONICET).