IOP drop during pregnancy recorded best by noncontact tonometer

Women in the third trimester of pregnancy showed significantly decreased IOPs when compared to control subjects using three methods of tonometry, according to Turkish researchers. Of the three methods, noncontact tonometry achieved the best intraobserver agreement during the third trimester, leading the researchers to suggest that ophthalmologists should use that method to monitor IOP levels in pregnant patients at risk for glaucoma.

Yusuf Akar, MD, and colleagues at the Akdeniz University School of Medicine measured IOP levels in the right eyes of 88 healthy women who were likely to become pregnant and of 94 healthy age-matched control patients. IOP measurements were taken using Goldmann, Schiötz and noncontact tonometry during a 3-week examination period within 6 weeks of conception and during each trimester of pregnancy, and at similar time intervals in the control subjects. Three readings with each tonometer were obtained at each interval, at least 1 day apart.

Keratometry, refractive error and mean visual acuity did not change in either control or pregnant subjects over the course of the study.

Pregnant women showed significant decreases in IOP measurements using all three tonometry methods during the third trimester. Intraobserver agreement also decreased significantly at this interval in the pregnant women using the Schiötz and Goldmann methods, but noncontact tonometry had perfect intraobserver agreement.

Both intraobserver and intertechnique agreement in IOP measurements of control subjects were not found to change significantly during the study.

The study is published in the January issue of Ophthalmologica.