IOP measurement reliability possible with multiple readings

Researchers can improve the reliability of IOP measurements by taking several readings over the course of the day instead of relying on a single office measurement when treating patients with glaucoma, according to a study.

Robert N. Weinreb, MD, and colleagues at the Hamilton Glaucoma Center in La Jolla, Calif., assessed the asymmetry of 24-hour IOP between right and left eyes of 41 patients with untreated open-angle glaucoma. Patients ranged in age from 40 to 78 years old.

IOP was measured every 2 hours with the patient in the sitting and supine positions from 7 a.m. until 11 p.m., and in the supine position only overnight.

No statistically significant difference was found between IOPs of the eyes at any of the time points. The strength of the association for mean IOP was only moderate. Residual values of more than 3 mm Hg were more common using a symmetric model than they were with a best-fit model.

“The current method of performing monocular therapeutic trials in glaucoma patients is unreliable,” the authors said.

The study is published in the March issue of Ophthalmology.