He went on to explain typical contrasts between pressures, such as an IOP that is slightly higher than intracranial/CSF pressure in normal patients, an IOP that is higher than the intracranial pressure in glaucoma patients, or the hypotony scenario in which IOP is lower than the intracranial pressure and the optic nerve complex moves anteriorly.
These different scenarios are important because 20% to 50% of glaucoma is normal-tension glaucoma, Dr. Berdahl said.
"If it was all about eye pressure, why would people with normal eye pressure get glaucoma in the first place?" he said.
He also pointed out that 8% of patients have severe glaucoma and get worse despite the use of trabeculectomies, tubes, or implants.
"How can we use this potential knowledge to help these patients?" he said.
Dr. Berdahl shared findings from previous research that found a pressure gradient occurring across the nerve head and that shows if you lower CSF pressure, you get nerve fiber layer defects and posterior cupping.
In some of his own research, Dr. Berdahl and fellow researchers found that patients with glaucoma have lower CSF pressure. He also has research demonstrating a translaminar pressure gradient bigger in normal-tension glaucoma and regular glaucoma compared with controls.