Glaucoma impairs the sight of over 70 million people worldwide, and yet very little is known about what causes it or how to cure it. More often than not, the eye condition shows no symptoms and once it leads to blindness it is irreversible.
Over 3 million Americans suffer from glaucoma, but only half of them know they have it. Up to recently, it was believed that, although doctors could provide significant relief by treating the disease, the condition did not have a possible cure.
However, scientists may now be changing their point of view. According to a recent study conducted on mice by scientists at MIT and the Massachusetts Eye and Ear, immune cells that are normally prohibited from venturing into our eyes in order to avoid inflammation may be able to enter the area, after all, eating away at our retinal cells.
An immune system unhinged
The study came to this conclusion after uncovering substantial evidence on why the body’s immune system turns on itself in the event of glaucoma. It turns out that when a patient gets afflicted by the neurodegenerative condition, the body mistakes the immune cells entering the eyes for a bacterial infection.
The study also revealed that people who suffer from glaucoma have five times more damaged immune cells in their eyes than people with normal vision. This led the scientists to make another hypothesis that the elevated levels of pressure in the eyes that are a common symptom of glaucoma might, in fact, be the body’s immune response to the sudden attack.
To evaluate their theory, the scientists searched for the presence of immune cells in the eyes of mouse test subjects with glaucoma. They uncovered T cells in the mice's eyes which should not have been there since the blood-retina barrier normally blocks lymphocytes from entering the sensitive eye region.
The researchers deduced that these T cells in glaucoma-afflicted eyes target the body’s heat shock proteins. Since the presence of T cells is high in the eyes of patients, it is believed that the body does not cooperate to fight the disorder, thus resulting in irreversible blindness.
Hope for a new treatment emerges
However, the findings suggest that the disorder can be treated by figuring out a way to block the system's autoimmune activity. “This opens a new approach to prevent and treat glaucoma,” said in a statement Jianzhu Chen, an MIT professor of biology, a member of MIT’s Koch Institute for Integrative Cancer Research, and one of the senior authors of the study.
Co-author of the study and associate professor of ophthalmology at Harvard Medical School and the Schepens Eye Research Institute of Massachusetts Eye and Ear Dong Feng Chen further believes the study's results may also offer renewed hope for other neurodegenerative disorders. “What we learn from the eye can be applied to the brain diseases, and may eventually help develop new methods of treatment and diagnosis,” he added.
The study was published August 10 in the journal Nature Communications.