EyeWorld India December 2018 Issue

18 EWAP FEATURE December 2018 in the academic and scientific field. “On the scientific side, it’s been millions of dollars, and hun- dreds of studies around this topic have been performed,” Dr. Berdahl said, pointing out that he thinks most ophthalmologists think this relationship is true. At a medical meeting 5 years ago, Dr. Berdahl said the audience was asked “Do you think CSF pressure plays a role in glaucoma pressure—yes or no?” About 95% said yes. Russell Swan, MD , Vance Thompson Vision, Bozeman, Montana, said when he was in residency 3–4 years ago the con- cept of CSF pressure in glaucoma was introduced but not widely discussed. Now, he added, over the last 1–3 years, he thinks there is a lot of discussion and a lot of journal articles about it. “I think there is fairly uni- fying agreement that it plays a significant role,” Dr. Swan said. “I think people are aware of it. I think they think it’s true, and they don’t have any idea what to do with that information,” Dr. Berdahl said. “[Currently,] we don’t get CSF pressures. We don’t obtain them with spinal taps on glaucoma patients, so we’re not getting that information on the front end, and even if we did, what do we do about it? We would lower eye pressure like we always do.” There is not a practical, clini- cal application for this informa- tion—at least not yet. Six years passed after Dr. Berdahl got the idea about the role of CSF pressure and glaucoma. During that time he was primarily thinking about how to measure CSF pressure noninvasively. Then, while reading an article about the visual loss that astronauts faced with long-term spaceflight, Dr. Berdahl thought he knew why a percentage were losing vision. “It’s the opposite of glaucoma, where CSF pressure is higher than eye pressure,” he said. This led him to think that if pressure could be added to the eye, maybe the pressure differential across the op- tic nerve head could be balanced. “How could we do that?” he wondered. “You could push on the eye with a thumb or something to raise the eye pressure, but maybe you could put on a pair of goggles and pressurize them. … Those gog- gles will essentially pressurize the eye, and the pressure in the eye would go up. … Then I thought, why couldn’t we depressurize the eye, creating a vacuum.” As a physics major, Dr. Ber- dahl said this idea is a simple application of Pascal’s law and hydrostatic physics. “The goggles act by changing atmospheric pressure,” explained Malik Kahook, MD , director of the glaucoma service and glau- coma fellowship, Slater Family En- dowed Chair in Ophthalmology, University of Colorado, Aurora. “The localized suction allows for control of the atmospheric pres- sure in and around the eye, poten- Balance Goggles are based on the concept that both intraocular pressure and intracranial pressure can play a role in the development of sight-threatening glaucoma—and thus also play a role in its treatment. Source: John Berdahl, MD Noninvasive, nonpharmacologic – from page 17