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Monitor diurnal fluctuation for clues to progression, clinician says
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John R. Samples, MD, advised physicians to monitor diurnal curves in their glaucoma patients more frequently. |
LAS VEGAS — Physicians should track diurnal curves in their glaucoma patients more often, despite the difficulty in doing so, said John R. Samples, MD.
“Diurnal fluctuation helps to track progression in glaucoma, although it is a pain in the gizzard to do,” Dr. Samples said here at the Ocular Surgery News Symposium, Glaucoma: Improving Your Odds. “But curves are important to your patients in terms of their progression.”
Dr. Samples, a program director of the meeting who has researched diurnal curves in glaucoma, explained the circadian rhythm of aqueous flow. He said it is highest in the morning; slightly lower in the afternoon; about one-half of the morning level during sleep. Normal flow is about 2.75 µL/minute during the day, he said.
Dr. Samples added that the beta-blocker timolol is “remarkably consistent on suppressing flow during the day but has no effect in sleeping subjects.”
Other factors influencing diurnal variation in IOP include corticosteroids and melatonin levels. Dr Samples said some patients ask him if physical and emotional stress can play a part in the fluctuation of their diurnal curves. He said stress can cause an increase in catecholamines, which cause the curve to fluctuate.