Corneal Biomechanical Changes in Third Trimester of Pregnancy

Physiological and pathological changes to the eye and vision during and after pregnancy

Pregnancy introduces a multitude of changes in the body, including hormonal fluctuations and metabolic changes, which can lead to atypical ocular signs and symptoms. Ocular manifestations range from fluctuations in vision, to microstructural changes in the retina and choroid, to dry eye disease. This narrative review highlights the range of pregnancy-related effects on the eye and vision that are likely to present in the context of routine eyecare. Specifically, physiological ocular changes and pathological ocular changes that manifest for the first time, or are exacerbated, in uncomplicated pregnancy are discussed. The literature has evolved from simply noting differences in the eye between pregnant and non-pregnant groups, to refining knowledge of the proposed underlying pathophysiology with the advent of newer technologies in eyecare. A particular focus of this review is navigating when pregnancy changes in the eye occur or peak during the gestational period, and whether the changes are short-lived or might extend past pregnancy. While many pregnancy-associated changes are temporary and resolve post-partum, it is also recognised that some changes persist after pregnancy, with a notable absence of literature on ocular changes with loss or termination of pregnancy. Currently or previously pregnant women (or those planning to become pregnant), and other health professionals, should be educated about the importance of seeking eyecare before, during and after pregnancy.

Retinal and choroidal microvascular features during pregnancy: a systematic review and meta-analysis

PURPOSE

To analyse retinal and choroidal microvasculature features in healthy pregnant women using optical coherence tomography angiography (OCTA).

METHODS

PubMed, Embase, Ovid, Web of Science and Cochrane Library were searched for published studies that compare retinal and choroidal microvasculature characteristics between pregnant females and non-pregnant females from inception to November 2023. The statistics were continuous variables. They were presented as the mean difference (MD) with a corresponding 95% CI. We used Review Manager software 5.4.1 for statistical analysis.

RESULTS

A total of 5 eligible studies involving 219 eyes in the pregnancy group and 186 eyes in the control group were included in the meta-analysis. The pooled results showed that the retinal deep capillary plexus vascular density (DCP VD) measured by OCTA was significantly higher in healthy pregnant women than in controls (MD 1.53; 95% CI 0.62 to 2.44; I2=0%; p=0.0009). However, differences between the two groups in the retinal superficial capillary plexus VD (SCP VD) (MD 0.41;95% CI -1.26 to 2.09; I2=85%; p=0.63), the foveal avascular zone (FAZ) (MD 0.01; 95% CI -0.01 to 0.03; I2=14%; p=0.18), the choriocapillaris VD (CC VD) (MD 0.76; 95% CI -1.11 to 2.64; I2=79%; p=0.43) were uncertain.

CONCLUSIONS

Our meta-analysis found that the DCP VD of healthy pregnant women was higher than that of non-pregnant controls. However, differences in SCP VD, FAZ and CC VD between the healthy pregnant women and the non-pregnancy controls were uncertain. Our findings can help to get a deeper understanding of retinal and choroidal microvascular characteristics during pregnancy.

Novel Correlation between TGF-β1/-β3 and Hormone Receptors in the Human Corneal Stroma

This study investigated the interplay between transforming growth factor beta (TGF-β1/T1 and TGF-β3/T3), and sex hormone receptors using our 3D in vitro cornea stroma model. Primary human corneal fibroblasts (HCFs) from healthy donors were plated in transwells at 106 cells/well and cultured for four weeks. HCFs were supplemented with stable vitamin C (VitC) and stimulated with T1 or T3. 3D construct proteins were analyzed for the androgen receptor (AR), progesterone receptor (PR), estrogen receptor alpha (ERα) and beta (ERβ), luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), gonadotropin-releasing hormone receptor (GnRHR), KiSS1-derived peptide receptor (KiSS1R/GPR54), and follicle-stimulating hormone subunit beta (FSH-B). In female constructs, T1 significantly upregulated AR, PR, ERα, FSHR, GnRHR, and KiSS1R. In male constructs, T1 significantly downregulated FSHR and FSH-B and significantly upregulated ERα, ERβ, and GnRHR. T3 caused significant upregulation in expressions PR, ERα, ERβ, LHR, FSHR, and GNRHR in female constructs, and significant downregulation of AR, ERα, and FSHR in male constructs. Semi-quantitative Western blot findings present the interplay between sex hormone receptors and TGF-β isoforms in the corneal stroma, which is influenced by sex as a biological variable (SABV). Additional studies are warranted to fully delineate their interactions and signaling mechanisms.

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

INTRODUCTION

Pregnancy causes an increase in central corneal thickness (CCT) and a reduction in intraocular pressure (IOP), especially in the third trimester. However, there is very limited published data regarding CCT and IOP in gestational diabetes mellitus (GDM) on diet control. This study is aimed to compare the means of CCT and IOP between pregnant women with GDM on diet control, healthy pregnant women, and healthy non-pregnant women.

METHODS

This is a comparative cross-sectional study. A total of 184 women were recruited and divided into the following three groups: 61 pregnant women with GDM on diet control, 63 healthy pregnant women, and 60 healthy non-pregnant women as control. All subjects have undergone ocular examination during their 36-40 weeks of gestation. CCT measurement was done using a specular microscope and IOP measurement using a non-contact tonometer. Data from the right eye were analyzed.

RESULTS

The mean age was 32 (4.0) years in GDM on diet control, 29 (3.0) years in healthy pregnant women, and 27 (5.4) years in healthy non-pregnant women. The number of gravidas was 2.5 (0.8) in women with GDM on diet control and 2.3 (0.8) in healthy pregnant women. There was a significant difference (p<0.05) in the mean CCT in women with GDM on diet control compared to healthy pregnant and healthy non-pregnant women. The mean IOP is significantly lower in both pregnant women with GDM on diet control and healthy pregnant groups, compared to the healthy non-pregnant women group.

CONCLUSION

Women with GDM showed significantly thicker mean CCT than healthy pregnant and non-pregnant women. The mean IOP is significantly lower in both pregnant women with GDM on diet control and healthy pregnant groups, compared to the healthy non-pregnant women group.

Biomechanical analysis of ocular diseases and its in vitro study methods

Ocular diseases are closely related to the physiological changes in the eye sphere and its contents. Using biomechanical methods to explore the relationship between the structure and function of ocular tissue is beneficial to reveal the pathological processes. Studying the pathogenesis of various ocular diseases will be helpful for the diagnosis and treatment of ocular diseases. We provide a critical review of recent biomechanical analysis of ocular diseases including glaucoma, high myopia, and diabetes. And try to summarize the research about the biomechanical changes in ocular tissues (e.g., optic nerve head, sclera, cornea, etc.) associated with those diseases. The methods of ocular biomechanics research in vitro in recent years are also reviewed, including the measurement of biomechanics by ophthalmic equipment, finite element modeling, and biomechanical analysis methods. And the preparation and application of microfluidic eye chips that emerged in recent years were summarized. It provides new inspiration and opportunity for the pathogenesis of eye diseases and personalized and precise treatment.