Cure for glaucoma soon, says new research

TORONTO - Cure for glaucoma which leads to blindness may be on its way.

Canadian researchers have discovered an unidentified form of circulation in the human eye which may provide important clues to glaucoma.

The human eye is considered to lack lymphatics - a circulation responsible for pumping fluid and waste out of tissues.

But now researchers at the University of Toronto and the local St Michael’s Hospital say the inability to clear that fluid from the eye is linked to glaucoma which currently affects over 66 million people worldwide.

“We challenged this assumption about a lack of lymphatics and discovered specialized lymphatic channels in the human eye,” lead researcher Yeni Yucel said in a university statement Monday.

A degenerative disease believed to be caused by the death of nerve cells at the back of the eye and in vision centres of the brain, glaucoma is often associated with elevated pressure in the eye, the researchers said.

Current treatments for glaucoma include eye drops or surgery to lower eye pressure either by reducing fluid formation or improving fluid drainage from the eye.

“Good vision depends on the stable flow of fluid into and out of the eye. Any disturbance of this delicate fluid balance can lead to high eye pressure and irreversible glaucoma damage,” said study co-author Neeru Gupta.

The researchers found that lymphatic circulation, distinct from blood circulation, carries a colourless fluid called lymph containing extra water, proteins and antigens through lymphatic vessels to lymph nodes and then to the blood stream.

This circulation is critical for the drainage of the fluid from tissues, clearance of proteins and immune monitoring of the tissue, they said. Using molecular tools and 3-D reconstruction, the researchers identified a rich network of lymphatic channels in the human eye. These findings were confirmed by electron microscopy.

“This discovery is exciting because it means we can focus on innovative treatment strategies for patients with glaucoma by specifically targeting this new circulation to lower eye pressure,” said Gupta.

According to the researchers, future studies will be directed at better understanding how to manipulate the lymphatic circulation in the eye.

“It is clear that if we want to develop new strategies to prevent blindness, we need to challenge existing beliefs, and hopefully open the door to new treatments for eye disease,” said lead researcher Yucel.

The study appears in the current issue of Experimental Eye Research.