Effect of pregnancy on intraobserver and intertechnique agreement in intraocular pressure measurements

To evaluate the effect of pregnancy on intraobserver and intertechnique agreement for intraocular pressure (IOP) measurements.

Right eyes of 88 healthy women who were likely to become pregnant and of 94 healthy age-matched females were included in the study. Complete ocular examinations were performed on each eye. IOP measurements were obtained by Goldmann, Schiotz and non-contact tonometers (NCT) during 3-week exam periods before (within 6 weeks of conception) and during pregnancy (first, second and third trimesters) for pregnant cases, and in similar time intervals for control subjects. In each exam period, three readings with each of three separate tonometers were obtained, at least 1 day apart. Intraobserver and intertechnique agreements for IOP measurements were assessed.

The mean visual acuity, keratometry and refractive error of both control and pregnant subjects did not change significantly during the study (all p values >0.01). In late pregnancy, pregnant cases demonstrated significant decreases in IOP measurements obtained with each of the three tonometers, and in intraobserver agreement with Goldmann and Schiotz tonometers (all p values <0.01). Intertechnique agreement of both Goldmann and Schiotz tonometers with NCT decreased significantly in the third trimester. Both intraobserver and intertechnique agreement in IOP measurements of control subjects were not found to change significantly during the study (all p values >0.01).

IOP significantly decreased in the third trimester of pregnancy. Perfect intraobserver agreement in IOP readings of pregnant subjects was obtained with NCT. This may suggest that NCT is a viable option for IOP measurements during the follow-up of pregnant patients at risk for glaucoma.