EyeWorld India December 2018 Issue

EWAP FEATURE 17 Noninvasive, nonpharmacologic, nonsurgical glaucoma therapy by Liz Hillman EyeWorld Senior Staff Writer AT A GLANCE • The role of cerebrospinal uid pressure on glaucoma has been well established in medical literature within the last 10 years, but how to apply that knowledge to help patients has not yet made it to the clinic. • The imbalance between IOP and cerebrospinal uid pressure in glaucoma can cause cupping of the optic disc and disruption of axonal transport, leading to damage of the optic nerve. • A team developed a set of goggles that essentially creates a vacuum over the eye, allowing on-demand, titratable IOP- lowering effects. • Proof-of-concept and in-human trials have been conducted, and a multicenter clinical trial is expected to begin within a year. A shift in the thinking of what causes glaucoma, a chance article about as- tronauts, and a company developing IOP-lowering goggles was born T o say that treatment for glaucoma has un- dergone a revolution within the last decade is an understatement. There are new surgical options (several con- sidered microinvasive glaucoma surgery [MIGS]) and new drug targets on the market. While there are surgical options and medica- tions still in the pipeline, there is also a nonsurgical and non- pharmacologic option that could offer first-of-its-kind, on-demand, titratable IOP lowering—and its use could be as simple as strapping on a pair of goggles. Currently dubbed Balance Goggles (Equinox, Sioux Falls, South Dakota), the idea is that the goggles create a vacuum over the eye to lower eye pressure. The concept of this product was born out of the idea that it’s not just IOP in glaucoma that causes dam- age to the optic nerve, but that it’s an imbalance between IOP and cerebrospinal fluid (CSF) pressure, and by decoupling these two pres- sures, a new therapeutic option would emerge. John Berdahl, MD , Vance Thompson Vision, Sioux Falls, South Dakota, published his first paper on the role of CSF pressure and glaucoma a decade ago . 1 Dr. Berdahl first got the idea about the role of cerebrospinal fluid pressure in glaucoma while scuba diving with his wife. With several hundred millimeters of mercury pressing on his body, including his eyes, he thought, why don’t scuba divers get glaucoma? It’s be- cause that same pressure is applied all over the body, he reasoned. So, was it possible that people with glaucoma had something going on with their CSF pressure and IOP? Conducting research, Dr. Berdahl and coinvestigators found that patients with various forms of glaucoma do indeed have an imbalance of IOP and CSF (in- tracranial) pressure, which causes cupping of the optic disc resulting in nerve damage over time. This, Dr. Berdahl said, can explain why even patients with low IOPs can still develop glaucoma (they might have an even lower CSF pressure) and why those with high IOPs might not develop glaucoma (they have an elevated protective CSF pressure). “Clearly, we’ve been missing a big picture in glaucoma for a long time,” Dr. Berdahl said. “In the United States, 30% of patients who have glaucoma never have a high eye pressure, and of those who have a high eye pressure, only 10% of them over 5 years go on to develop glaucoma. The story isn’t just about eye pressure in isolation. We think it is eye pressure relative to cerebrospinal fluid pressure that is the underly- ing cause of disease. If that is the underlying cause of the disease, how do we use that information to develop technologies that can help people?” Dr. Berdahl’s initial paper in 2008 has since been cited nearly 300 times, indicating strong re- search and support to this theory “ Drops and prior surgical procedures are effective at lowering IOP to a certain level, then for those who need additional IOP lowering, I think the goggles would be a great option. ” - John Berdahl, MD continued on page 18 December 2018