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Gravity linked to diurnal fluctuation in macular edema, researcher says
SAO PAULO, Brazil — Gravity and hydrostatic pressure appear to play a role in diurnal variation in the severity of diabetic macular edema, according to a retina specialist.
“Our study supports the hypothesis that gravity and hydrostatic pressure play a major role in determining time-related shifts in clinically significant macular edema,” said Francesco Bandello, MD, speaking here at the World Ophthalmology Congress.
Dr. Bandello said he and colleagues examined diurnal fluctuations of macular thickness in 10 diabetic patients with an average macular thickness of 574 µm.
During the course of the day, patients tested when standing upright demonstrated a 20% decrease in mean foveal thickness compared to their foveal thickness in a recumbent position, Dr. Bandello said.
He said systemic factors, including fluctuations in blood pressure and body temperature, were ruled out as possible causes of diurnal changes.
One explanation for the change, he noted, could be the physical shift of a patient from the sleeping recumbent position to the awake upright position.
“The high hydrostatic pressure in the recumbent position may increase [the fluid] … to the tissue of the visual compartment,” Dr. Bandello said.