Changes in corneal biomechanics during pregnancy in Chinese healthy female

Abstract

Purpose: To evaluate the changes of corneal biomechanics and the intraocular pressure during pregnancy in a Chinese healthy female population. Methods: A total of 222 unrelated Chinese females were recruited: 52 non-pregnant, 15 pregnant in the first trimester, 68 pregnant in the second trimester, and 87 pregnant in the third trimester. The intraocular pressure and corneal biomechanical parameters, including corneal-compensated intraocular pressure, Goldmann-correlated intraocular pressure, corneal hysteresis, and corneal resistance factor, were measured by an Ocular Response Analyzer G3. Central corneal thickness was measured by Lenstar (LS900). Results: Corneal hysteresis and corneal resistance factor were significantly higher in pregnant women at the second and third trimesters. Corneal-compensated intraocular pressure was lower in women at the third trimester of pregnancy ( p = 0.023), but the difference became insignificant after adjustment for corneal hysteresis. Central corneal thickness was marginally higher in pregnant women than non-pregnant women ( p = 0.032). There was a negative correlation between corneal-compensated intraocular pressure and corneal hysteresis ( r = −0.337, p < 0.001) and a positive correlation between central corneal thickness and corneal hysteresis ( r = 0.711, p < 0.0001). After adjustment for corneal-compensated intraocular pressure, corneal hysteresis remained significantly higher in the second and third trimesters of pregnant women than non-pregnant women ( p = 0.031, p = 0.005). Conclusion: This study revealed a significant increase in corneal hysteresis and corneal resistance factor in the second and third trimesters. The increase of corneal hysteresis was independent of corneal-compensated intraocular pressure, indicating pregnant females have unique characteristics in corneal-compensated intraocular pressure and corneal biomechanical properties that may be related to glaucoma and corneal ectatic diseases in pregnancy.

Pregnancy-induced changes in ocular biomechanics are maternal hormone- related in healthy Chinese pregnant women

“…In our study, the IOP decreased throughout the trimesters, particularly during the third trimester, and returned to normal levels at postpartum, which con rmed the observation of many studies and has been well documented in the literature [9][10][11] . Although the exact mechanism responsible for the IOP reduction during pregnancy is not well known, there are several general agreements on the possible factors.…”

Central Corneal Thickness and Intraocular Pressure in Women With Gestational Diabetes Mellitus

“…High estrogen levels during pregnancy, especially in the third trimester, cause stromal hydration and result in thicker CCT [ 10 ]. This is further evidenced by the presence of estrogen receptors in the nuclei of the stromal and endothelial cells of the cornea [ 16 , 17 ]. Another postulation of thicker CCT during pregnancy is due to the secondary effect of systemic water retention on the cornea by estrogen-induced upregulation of the renin-aldosterone system [ 17 , 18 ].…”

“…Previous studies have postulated that IOP reduction can be due to various mechanisms. High progesterone levels during pregnancy can cause an increase in the fluid outflow from the eye and a reduction in the episcleral venous pressure resulting from decreased total systemic vascular resistance [ 16 , 18 , 24 ]. Wang et al and Shrinkhal et al have added that human chorionic gonadotrophin, nitric oxide, endothelin-I, eicosanoids, and relaxin also play a role in the reduction of IOP in pregnancy [ 9 , 24 ].…”

Cambios oculares durante el embarazo

“…El edema corneal durante el embarazo es uno de los fenómenos mejor descritos sobre este periodo, siendo provocado por un aumento en el contenido acuoso, que puede causar intolerancia a los lentes de contacto. Por otro lado, se ha mencionado, en algunos estudios, que el queratocono ha progresado durante el embarazo, y que el mismo es persistente incluso posterior al parto (3,9). En el estudio realizado por el Dr. Naderan, en el cual se dio un seguimiento un grupo de 22 ojos con un queratocono estable de dos años de evolución, y se evaluaron en el periodo de preembarazo (con el plan de quedar embarazadas), al tercer trimestre (34 semanas) y seis meses postparto, se concluyó que hubo un aumento en el progreso de la enfermedad (evidenciada en aumento de la curvatura y adelgazamiento de la córnea) en todas las etapas de la evaluación, e inclusive se sugiere que se deberían considerar medidas preembarazo (fortalecimiento del colágeno corneal por medio de la riboflavina, procedimiento llamado cross-linking) (10).…”