Pregnancy-induced Changes in Corneal Biomechanics and Topography Are Thyroid Hormone Related.

Abstract

To identify biomechanical and topographic changes of the cornea during pregnancy and the postpartum period and its association to hormonal changes. Prospective single-center observational cohort study. Participants were 24 pregnant women (48 eyes), monitored throughout pregnancy and after delivery. Biomechanical and topographic corneal properties were measured using the Ocular Response Analyzer (ORA) and a Scheimpflug imaging system (Pentacam HR) each trimester and 1 month after delivery. At the same consultations blood plasma levels of estradiol (E2) and thyroid hormones (TSH, T3t, T4t) were also determined. A factorial MANCOVA was used to detect interactions between hormonal plasma levels and ocular parameters. Significant differences in corneal biomechanical and topographic parameters were found during pregnancy in relation to T3t (p = .01), T4t (p < .001), T3t/T4t (P = .001), and TSH (p = .001) plasma levels. E2 plasma levels (p = .092) and time period of measurement (p = .975) did not significantly affect corneal parameters. TSH levels significantly affected the maximal keratometry reading (p = .036), the vertical keratometry reading (p = .04), and the index of height asymmetry (p = .014). Those results persist after excluding hypothyroidism patients from the statistical analysis. Hormonal changes affecting corneal biomechanics and topography during pregnancy could be thyroid related. Dysthyroidism may directly influence corneal biomechanics and represents a clinically relevant factor that needs further investigation.