Glaucoma may be an autoimmune disease: Study

Glaucoma, an eye disease which affects nearly 70 million people worldwide, may be an autoimmune disease, according to a study.

Autoimmune disease is a condition in which the immune system attacks the body's own cells.

Glaucoma is something of a mystery despite its prevalence, said researchers at the Massachusetts Institute of Technology (MIT) in the US.

Little is known about the origins of the disease, which damages the retina and optic nerve and can lead to blindness.

Published in the journal Nature Communications, the study conducted in mice showed that the body's own T cells are responsible for the progressive retinal degeneration seen in glaucoma.

These T cells appear to be primed to attack retinal neurons as the result of previous interactions with bacteria that normally live in our body, researchers said.

It could be possible to develop new treatments for glaucoma by blocking this autoimmune activity, they said.

"This opens a new approach to prevent and treat glaucoma," said Jianzhu Chen, a professor at MIT.

One of the biggest risk factors for glaucoma is elevated pressure in the eye, which often occurs as people age and the ducts that allow fluid to drain from the eye become blocked.

The disease often goes undetected at first; patients may not realise they have the disease until half of their retinal ganglion cells have been lost.

The researchers looked for immune cells in the retinas of these mice and found that indeed, T cells were there.

This is unusual because T cells are normally blocked from entering the retina, by a tight layer of cells called the blood-retina barrier, to suppress inflammation of the eye.

The researchers found that when intraocular pressure goes up, T cells are somehow able to get through this barrier and into the retina.

They generated high intraocular pressure in mice that lack T cells and found that while this pressure induced only a small amount of damage to the retina, the disease did not progress any further after eye pressure returned to normal.