Evaluation of the Choroid in Women with Uncomplicated Pregnancy

Subfoveal choroidal thickness in pregnancy: A systematic review with meta-analyses

Pregnancy induces a variety of changes in the eye. Mapping these changes provides a pathophysiological basis for understanding pregnancy-associated ocular disorders. In this systematic review and meta-analysis, our aim was to determine how pregnancy affects subfoveal choroidal thickness and to explore temporal changes in subfoveal choroidal thickness during pregnancy and postpartum. On April 7, 2024, we searched eight literature databases for studies which used macular optical coherence tomography to evaluate subfoveal choroidal thickness in healthy pregnant women. We identified 26 studies summarizing data from 1935 healthy women, of which 1096 were pregnant and 839 non-pregnant. We found that pregnant women had a subfoveal choroidal thickness which was 31.1 μm (95% CI: 19.4-42.7 μm) thicker than non-pregnant women. No statistically significant changes were observed throughout trimesters. From the 3rd trimester to postpartum, we found a reduction in the subfoveal choroidal thickness at -41.9 μm (95% CI: -68.5 to -15.2 μm). In conclusion, in healthy women without ocular disease, pregnancy is associated with a thicker subfoveal choroid indicating a higher choroidal perfusion. Choroidal thickness remains stable across trimesters and is reduced postpartum, indicating a temporary physiological adaptation during pregnancy.

Changes in Optical Coherence Tomography Angiography Precede Clinical Onset of Placental Insufficiency

Purpose

This prospective cohort study examined the use of optical coherence tomography angiography (OCTA) to detect in vivo retinal and choroidal variations associated with placental insufficiency, manifesting as fetal growth restriction (FGR) and hypertensive disorders of pregnancy (HDP).

Methods

Pregnant women were imaged with OCTA from gestational week 16 and every 4 weeks until week 36. Pregnancy outcomes were categorized into three groups: uncomplicated, complicated by late FGR, or complicated by HDP after 32 weeks. OCTA metrics, including retinal perfusion density (PD), vessel length density (VLD), and choriocapillaris flow deficits (CCFDs), were compared between groups.

Results

In uncomplicated pregnancies, OCTA metrics remained stable throughout gestation. In contrast, the FGR group exhibited significant overall increases in superficial VLD (P = 0.016), decreases in deep VLD (P = 0.029), and increases in CCFDs (P = 0.002) throughout pregnancy when compared to the uncomplicated group. The HDP group showed significant overall decreases in both PD (P < 0.001) and VLD (P = 0.019) in the deep layer when compared to the uncomplicated group. Furthermore, CCFDs demonstrated strong potential for early prediction of FGR as early as week 16 (area under the curve = 0.73; P = 0.012).

Conclusions

Our pilot study highlights the potential of OCTA to identify retinal and choroidal variations as biomarkers for pregnancy complications, particularly increased CCFDs in FGR.

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.

IMI-The Dynamic Choroid: New Insights, Challenges, and Potential Significance for Human Myopia

The choroid is the richly vascular layer of the eye located between the sclera and Bruch's membrane. Early studies in animals, as well as more recent studies in humans, have demonstrated that the choroid is a dynamic, multifunctional structure, with its thickness directly and indirectly subject to modulation by a variety of physiologic and visual stimuli. In this review, the anatomy and function of the choroid are summarized and links between the choroid, eye growth regulation, and myopia, as demonstrated in animal models, discussed. Methods for quantifying choroidal thickness in the human eye and associated challenges are described, the literature examining choroidal changes in response to various visual stimuli and refractive error-related differences are summarized, and the potential implications of the latter for myopia are considered. This review also allowed for the reexamination of the hypothesis that short-term changes in choroidal thickness induced by pharmacologic, optical, or environmental stimuli are predictive of future long-term changes in axial elongation, and the speculation that short-term choroidal thickening can be used as a biomarker of treatment efficacy for myopia control therapies, with the general conclusion that current evidence is not sufficient.

Evaluation of Choroidal Thickness during Pregnancy and Postpartum: A Longitudinal Study

Purpose

To assess the longitudinal changes of choroidal thickness using enhanced depth imaging optical coherence tomography (EDI-OCT) during pregnancy and postpartum.

Methods

The study included 23 eyes of 23 healthy pregnant women and 23 eyes of 23 healthy nonpregnant women. Choroidal thickness was measured manually with EDI-OCT at seven locations: The fovea, 500, 1000, and 1500 μm temporal (T) from the fovea and 500, 1000, and 1500 μm nasal (N) from the fovea. Measurements were obtained at each pregnancy trimester and 6 weeks postpartum and in the follicular phase of the menstrual cycle for the control group.

Results

The mean subfoveal choroidal thickness was 410.2 ± 82.4 μm, 434.8 ± 79.6 μm, 433.5 ± 80.3 μm, and 395.0 ± 71.1 μm in the first, second, and third trimesters and 6 weeks postpartum, respectively. In all seven measured locations, statistically significant changes were noted during pregnancy and postpartum in the choroidal thickness (P < 0.001). Choroidal thickness increased from the first trimester to the second and third trimester, after which it decreased at postpartum. Choroidal thickness was greater in the pregnant group during pregnancy and postpartum compared to the control group (P < 0.001).

Conclusions

This study indicated significant change in choroidal thickness at seven locations measured with EDI-OCT throughout pregnancy and 6 weeks after delivery. We showed that 6 weeks after delivery, choroidal thickness remains significantly higher than nonpregnant subjects.

Vascular Choroidal Alterations in Uncomplicated Third-Trimester Pregnancy

(1) Purpose: To evaluate the anatomy and perfusion of choroidal substructures in third-trimester pregnant women using optical coherence tomography (OCT) and OCT angiography (OCTA) imaging. (2) Methods: In this cross-sectional study, women in their third trimester of uncomplicated pregnancy and non-pregnant age-matched women were recruited. Participants underwent enhanced depth imaging (EDI) OCT and OCTA. Subfoveal choroidal thickness (SFCT), as well as choroidal sublayer perfusion, were compared between groups. (3) Results: In total, 26 eyes of 26 pregnant and 26 eyes of 26 non-pregnant women were included. The median age in both groups was 29 years. The median SFCT was 332 (211–469) µm in the pregnant group and 371.5 (224–466) µm in the non-pregnant cohort (p = 0.018). The median choriocapillaris perfusion (CCP) was significantly lower in the pregnant group (46% vs. 48%, p = 0.039). Moreover, Haller’s layer perfusion correlated significantly with mean arterial pressure in non-pregnant women (CC = 0.430, p = 0.028) but not in pregnant ones (CC = 0.054, p = 0.792). (4) Conclusions: SFCT was found to be thinner and CCP was lower in third-trimester pregnant women. Hormonal changes during pregnancy and consecutive impacts on autoregulation of small choroidal vessels might play an important role. Therefore, altered choroidal measurements during third-trimester pregnancy should be carefully evaluated as, to some extent, it could be a normal physiological change.

Neuro-ophthalmology and Pregnancy

PURPOSE OF REVIEW

This article summarizes the impact of pregnancy on neuro-ophthalmic pathways and presents an approach to the evaluation of pregnant women who have neuro-ophthalmic symptoms or signs.

RECENT FINDINGS

Advances in noninvasive ophthalmic imaging have increased knowledge of the impact of pregnancy on ocular blood flow, which may have relevance for understanding the impact of preeclampsia and eclampsia on the eye.

SUMMARY

The framework for approaching neuro-ophthalmic symptoms and signs in pregnant women is similar to the general approach for people who are not pregnant. Visual symptoms are common in preeclampsia and eclampsia. Some diseases that impact the neuro-ophthalmic pathways are more common in pregnant women. Pregnancy should be considered when recommending the workup and treatment for neuro-ophthalmic symptoms and signs.

Visualising the choriocapillaris: Histology, imaging modalities and clinical research - A review

The choriocapillaris plays a considerable role in the normal physiology of the eye as well as in various diseases. Assessing the changes in the choriocapillaris can therefore provide important information about normal ageing and pathogenesis of visual impairment, and even some systemic diseases. In vivo imaging of the choriocapillaris has evolved from non-depth resolved, dye-based angiography to advanced, high-resolution optical coherence tomography angiography (OCTA). However, the intricate microvascular networks within the choriocapillaris are still beyond the resolving limits of most OCTA instruments. Knowledge of histology, meticulous image acquisition methods, recognition of artefact and post-acquisition processing techniques are necessary for optimising OCTA choriocapillaris images. Qualitative and quantitative analyses of the choriocapillaris provide clinical information in age-related macular degeneration (AMD), diabetic retinopathy (DR), pathologic myopia and central serous chorioretinopathy (CSC). Furthermore, studies have revealed choriocapillaris changes in posterior uveitis that are correlated with treatment outcome and have important prognostic significance. In addition to retinal diseases, choriocapillaris changes have been observed in systemic vascular diseases and complications associated with pregnancy.

Assessment of the choroidal structure in pregnant women in the first trimester

We investigated the anatomical differences in the choroidal structure between pregnant women in the first trimester of pregnancy and age-matched healthy nonpregnant women using enhanced depth imaging optical coherence tomography (EDI-OCT) and choroidal binarization analysis. The main parameters measured in the two study groups, namely, pregnant women in the first trimester and healthy nonpregnant women, were choroidal thickness and the choroidal luminal area. Binarization of the EDI-OCT images from each patient was performed, and the choroidal vascularity index (CVI) was calculated. The correlations between the baseline characteristics of the subjects and the CVI were investigated using linear mixed model analysis. As a result, there was no statistically significant difference in the mean age, best-corrected visual acuity, axial length, central retinal thickness, subfoveal choroidal thickness, systolic blood pressure (BP), or diastolic BP between the two study groups. Conversely, a significant difference was observed in the CVI (P = 0.012) between the two groups. The multivariate analysis identified a significant correlation between the CVI and the systolic BP (P = 0.0044, linear mixed test). Taken together, a larger choroidal luminal area was associated with a higher systolic BP, especially in the first trimester of pregnancy. Our findings may provide further insight into the choroidal changes that occur during pregnancy.