IOP measurement paradigm shifting, surgeon says

MIAMI — Fluctuations in IOP are more accentuated in patients with glaucoma than in "normal" patients, and knowing when such peaks occur is important for controlling those fluctuations, according to a physician speaking here.

Felix Gil, MD, presented a possible new paradigm for better IOP monitoring in glaucoma patients at Bascom Palmer Eye Institute's Inter-American Course in Clinical Ophthalmology.

"We take the IOP in our patients once or twice a year, and it takes 2 seconds. That represents exactly 2 seconds of the 86,400 seconds we have in a day," Dr. Gil said through an interpreter. "So we are having a single spot-check, but what happens the rest of the day? We do not know, and this is part of our ignorance."

Variations in pressure larger than 3 mm Hg should be seen as "red flags" Dr. Gil noted.

"What is important is not that the patient should reach 14 mm Hg just because that is a good pressure, but that 14 mm Hg is maintained plus or minus 3 mm Hg throughout the day. That is the paradigm shift," he said.

The only way to control peaks of 3 mm Hg ore more is to know when they happen, Dr. Gil said, and the only way to know where they happen is to measure IOP throughout 24 hours.

"These are the silent killers. These peaks occur when [patients] are not in office hours," he said.

To estimate 24-hour IOP, Dr. Gil recommended measuring IOP at 1 a.m. and 6 a.m. while the patient is lying down, and then at 9 a.m., 12 p.m., 3 p.m., 6 p.m., 9 p.m. and 11 p.m.

"Or I use the Barrone method, where the patient lies down, and I take pressures at 8 a.m. and 9 a.m. after 1 hour of resting," he said. "This will give us 70% reproducibility in patients with glaucoma."