GLAUCOMA IS THE SECOND MOST COMMON CAUSE OF BLINDNESS IN CANADA.
The disease, which gradually steals sight without warning and often without symptoms, affects an estimated 65 to 70 million people worldwide.

The mechanisms of glaucoma damage are poorly understood, making this common disease difficult to treat. But Ross Ethier is working toward a solution by marrying engineering and medicine.

World-renowned in the field of biofluid mechanics, Ethier - a professor in mechanical and industrial engineering who is also cross-appointed to the Institute of Biomaterials and Biomedical Engineering and the Faculty of Medicine's ophthalmology department - is collaborating with clinical ophthalmologists, glaucoma specialists, optometrists and biologists to understand how pressure in the eye is controlled, how and why it becomes elevated and how it damages optic nerve cells.

"Researchers don't understand the causal relationship between pressure in the eye and nerve cell death. It's terra incognita," says Ethier. He finds the riddle intriguing. "Why are people walking around with high pressure and optic nerves that are just fine, yet there are people with normal pressure whose optic nerves show damage? Pressure reduction is the current mainstay of glaucoma therapy but, clearly, it's not the whole story."

The eye continually produces fluid to keep its clear tissues healthy. This fluid must drain out in a way that pressure on the eye does not get too high or too low - because either extreme can result in blindness. To exit, the fluid moves to the front of the eye, then drains through a spongy, porous area called the trabecular meshwork, along a passageway called Schlemm's canal and into collecting ducts. In the case of glaucoma, there is a drainage problem in this outflow pathway.

Ethier and his team are studying the cells that form the lining of Schlemm's canal to determine whether this area plays a role in increasing resistance to the flow of fluid, preventing it from draining out of the eye normally. They are also using computer-modeling techniques to learn what factors at a molecular level might contribute to nerve death.

Ethier is already making progress, having demonstrated differences in the cytoskeleton - the network of structural proteins - of normal and glaucomatous eyes. As he pulls up images on his computer illustrating the difference, he points out the tangled, knotted-up appearance of the eye affected by glaucoma, in comparison with the smooth lines in the image of the cytoskeleton of a normal eye. "We are the only group investigating this."

Finding his niche has paid off. Ethier's research is considered leading edge by colleagues in the field. He speaks regularly at conferences around the world and receives strong research support from the Canadian Institutes of Health Research, the Glaucoma Research Society of Canada and Alcon Pharmaceuticals Ltd.

His latest project is a mechanical shunt to assist in controlling pressure, which he recently patented with colleagues. "There are other devices," he says, "but they don't work very well, so doctors tend to use them only as a last resort." Ethier's new device fills a tall order: "It had to be small enough to fit on the surface of the eye, be bio-compatible, have no moving parts, last 30 years, be cheap and not require any external power source." His shunt, only two millimetres thick, is intended to bypass the eye's plugged drainage system and ensure a constant flow of fluid. "I'm excited about its potential. But the proof will be in how well it performs in trials over the next few years."
Reprinted from Skule Magazine

Ethier describes glaucoma as an "insidious, chronic, progressive disease."

"In glaucoma, the optic nerve, which is responsible for carrying the images we see from the retina to the brain, gets damaged.

In most cases this happens because the pressure in the eye is too high."

Current treatment centres on lowering elevated pressure in the eye. But it is often painful and tedious. Medication can result in side effects, including allergic reactions, blurred vision and changes in cardiac activity, including rapid heart rate or fluctuations in heart rhythm. If eye drops or laser surgery do not lower the pressure adequately, doctors may perform filtering microsurgery, in which a tiny drainage hole is made in the sclera, the white part of the eye, to allow fluid to flow out of the eye.

Even young, seemingly healthy eyes can be subject to elevated pressure and, possibly, glaucoma. For example, performer and songwriter Ray Charles lost his sight to glaucoma when he was only seven. While Ethier's research is still a long way from a new therapy, it is opening new avenues of understanding, gaining the attention and respect of researchers worldwide and renewing hope for viable treatment.