Visual acuity changes during pregnancy and postpartum: a cross-sectional study in Iran

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.

Myopia and its associated factors among pregnant women at health institutions in Gondar District, Northwest Ethiopia: A multi-center cross-sectional study

Background

Myopia is the most common form of uncorrected refractive error with a growing burden worldwide. It is the principal complaint of most women during pregnancy. Although myopia has led to several consequences across the standard life of pregnant women, there is no previous study in Ethiopia regarding this topic. Thus, this study determined the prevalence of myopia and identifies its associated factors among pregnant women attending antenatal care units at governmental health institutions in Gondar City District, Northwest Ethiopia.

Methods

An institution-based cross-sectional study design was conducted from 08 February to 08 April 2021. From the selected health centres, study participants were recruited by systematic random sampling technique. A pre-tested, structured-interviewer-administered questionnaire consisting of socio-demographic variables, obstetric and clinical-related variables was used to collect the required data. Non-cycloplegic refraction was performed using trial lenses, trial frames, and retinoscopy in a semi-dark examination room. EpiData 3 and STATA 14 were used for data entry and statistical analysis respectively. Both bivariable and multivariable binary logistic regression analyses were executed to identify associated factors of myopia. Variables with a p-value ≤0.05 in the multivariable logistic regression analysis were declared as statistically significant with myopia. Model fitness was checked by Hosmer and Lemeshow goodness of test (at p > 0.05).

Results

A total of four-hundred and twenty-three pregnant women participated with a 100% response rate in this study. The overall prevalence of myopia among pregnant women was 26.48% (95% CI: 22.48-30.91). Eighty-Eight (20.81%) and Eighty-Four (19.85%) of the study participants had myopia in their right and left eyes respectively. The prevalence of myopia was significantly associated with age (AOR = 1.17; 95% CI: 1.09-1.28), the third trimester of gestation (AOR = 2.05, 95% CI: 1.08-3.90), multi & grand multipara (AOR = 3.15; 95% CI: 1.59-6.25), and history of contraceptive use (AOR = 3.30; 95% CI: 1. 50-7.28).

Conclusion

The finding of our study shows that there is a higher prevalence of myopia among pregnant women in our study area. Further prospective analytical studies regarding visual systems among pregnant women, particularly as a result of pregnancy, are strongly recommended.

Changes in Refractive and Optometric Findings During Pregnancy

Background: Pregnancy-induced changes in the physiological responses during the gestational period can affect the eye. This study aimed to evaluate the effect of pregnancy on visual, refractive, vergence, and accommodative status. Methods: In this cross-sectional study, twenty-five healthy pregnant women with a mean age of 29±3.1 were examined. All of the subjects underwent comprehensive ophthalmologic examinations, including anterior segment and fundus examinations and tonometry. Refractive error was determined in each trimester using Autokeratometer. Furthermore, near the point of convergence (NPC), best-corrected visual acuity (BCVA), and near the point of accommodation (NPA) were measured. Data analysis was performed using SPSS version 22. To compare the data during pregnancy, repeated measures analysis of variance (ANOVA) was performed. Results: During pregnancy, in the right and left eye, spherical equivalent (SE) had a myopic shift from -0.13 to -0.35 D and +0.096 to -0.23 D, respectively (p=0.049 and p=0.020, respectively). Also, in the right and left eyes BCVA significantly decreased from -0.13 to 0.00 and -0.14 to 0.00 LogMAR, respectively (p=0.039 and p=0.045, respectively). NPA and NPC did not change statistically significantly during pregnancy (p=0.385, and p=0.801, respectively). Conclusion: Due to the unstable hormonal status, a myopic shift and decrease in BCVA occur during pregnancy. So, any change in their spectacle prescription, fitting of contact lenses, performing refractive surgeries, etc., during this period should be postponed.

Visual impairment and associated factors among pregnant women attending antenatal care units at health institutions in Gondar City Administration, Northwest Ethiopia

Background

Visual impairment is a major public health concern among women of reproductive age groups in Ethiopia, which is getting worse during pregnancy. Though visual impairment has lots of serious consequences across the life course of pregnant women, there is no previous study on this topic in Ethiopia. Thus, this study determined the prevalence of visual impairment and identified associated factors among pregnant women attending antenatal care units at the governmental health institutions in Gondar City Administration, Northwest Ethiopia.

Methods

An institution-based cross-sectional study was conducted. A systematic random sampling technique was used to recruit the study participants. We used an interviewer-administered questionnaire comprising of socio-demographic, clinical and pregnancy-related variables to collect the required data. Snellen’s illiterate “E” chart was used to determine visual impairment. EpiData 3 and Stata 14 were used for data entry and statistical analysis, respectively. Both bivariable and multivariable binary logistic regression analyses were executed to identify associated factors of visual impairment. Variables with a p-value ≤0.05 in the multivariable logistic regression analysis were declared as statistically significant with visual impairment.

Results

A total of 417 (response rate = 98.6%) participants were involved in this study, with a median age of 27 years. The overall prevalence of visual impairment was 22.5% (95% CI: 18.5–26.6). Thirty (7.2%) and thirty-two (7.7%) of the study participants had moderate to severe visual impairments in their right and left eyes, respectively. Participants aged from 31 to 49 years (AOR = 2.1; 95% CI: 1.1–4.0), being 3rd trimester (AOR = 2.4; 95% CI: 1.3–4.5), multi & grand multipara (AOR = 2.3; 95% CI: 1.2–4.6), and history of contraceptive use (AOR = 2.7; 95% CI: 1.2–6.3) had higher chance of visual impairment.

Conclusion

The magnitude of visual impairment among pregnant women was high in the study area. Therefore, routine screening and evaluation of pregnant women for visual condition during antenatal care visits is recommended. Further investigations of visual changes, particularly as a result of pregnancy, are warranted.

Laser refractive surgery in pregnant or breastfeeding patients

This systematic review reported the outcomes of laser corneal refractive surgery in pregnant or breastfeeding patients. This study was performed by searching in PubMed, Web of Science, and Scopus databases, on June 15, 2020. Included were 128 eyes from a total of 64 patients, with the mean maximum follow-up was 39.2 ± 36.14 months. Time from surgery to complication ranged from 1 to 67 months, with a mean value of 23.42 ± 22.23 months. Photorefractive keratectomy and laser in situ keratomileusis surgery seem to be stable procedures that are not modified during pregnancy and safe to complete during breastfeeding. Nevertheless, the lack of weight prospective research avoids having a greater certainty on this matter, and because of transitory nature of pregnancy and breastfeeding, it could still be contemplated that surgery risk outweigh the benefits. Additional investigation will be necessary to clarify these issues.

A Narrative Review of the Complex Relationship between Pregnancy and Eye Changes

Pregnancy is a condition often characterized by changes that occur in different parts of the body. Generally, the eyes suffer several changes during pregnancy that are usually transient but may become permanent at times. This may occur due to the release of placental hormones and those of maternal endocrine glands and fetal adrenal glands. Due to hormonal influences, physiological ocular changes during pregnancy have been shown in Caucasian women, so corneal sensitivity, refractive status, intraocular pressure, and visual acuity may change during pregnancy. Within this review, all studies that referred to physiological aspects and to changes of ocular pathology of pregnancy, the effect of the pregnancy on pre-existing (diabetic retinopathy, neuro-ophthalmic disorders) eye disorders, postpartum ocular changes, the intraocular pressure and the effect of hypotensive ophthalmic medicine during pregnancy, the connection between pregnancy and the neuro-ophthalmic pathology, as well as the role of anesthesia were analyzed.

Evaluation of choroidal thickness and choroidal vascularity index during pregnancy

OBJECTIVE

To assess the choroidal structural characteristics in the first and third trimesters in pregnant women using enhanced depth imaging optical coherence tomography and binarization method.

DESIGN

Prospective study.

PARTICIPANTS

Twenty-five eyes of 25 pregnant women in the first trimester (group 1) and 25 eyes of 25 pregnant women in the third trimester (group 2) were examined. Healthy age-matched 25 participants were enrolled as a control group (group 3).

METHODS

The choroidal thickness (CT) was measured at 3 points; subfoveal, 1500 μm nasal to the fovea, and 1500 μm temporal to the fovea. Total choroidal area, luminal area, stromal area, stroma/lumen ratio, and choroidal vascularity index (CVI) were measured by Image-J software.

RESULTS

The mean subfoveal and nasal CT were statistically significantly increased in group 1 compared with controls (p = 0.005 and p = 0.004, respectively). The mean temporal CT was statistically significantly increased in group 1 compared with groups 2 and 3 (group 1 vs group 2, p = 0.043; group 1 vs group 3, p = 0.011). The mean total choroidal area, stromal area, and luminal area were significantly increased in groups 1 and 2 compared with control group (p < 0.001, p < 0.001, p < 0.001, and p < 0.001, p = 0.002, p = 0.002, respectively). There were no statistically significant differences among groups in terms of mean stroma/lumen ratio and CVI (p = 0.148 and p = 0.312, respectively).

CONCLUSIONS

There was a significant increase in subfoveal, temporal, and nasal CT in the first trimester. Total choroidal, stromal, and luminal areas were significantly increased in the first and third trimesters.

Correlations between joint kinematics and dynamic balance control during gait in pregnancy

BACKGROUND

Dynamic balance control degrades during pregnancy, but it is not yet understood why. Mechanical aspects of the body should directly affect walking balance control, but we have recently published papers indicating that weight gains during pregnancy explain very little dynamic balance changes. Our goal was to determine if lower extremity joint kinematic changes are an indicator of walking balance control. This information is vital to understanding the route by which pregnancy increases fall risk.

METHODS

Twenty-three pregnant women were tested at five different times in the 2nd and 3rd trimesters of pregnancy. Participants performed walking trials at a self-selected pace. Motion capture was used to measure joint kinematics (discrete and coordination variables) and body center of mass motion. Changes over time were statistically analyzed. Correlations between kinematics and walking balance were modelled with hierarchical multiple regression models.

RESULTS

As pregnancy progresses, it appears that a more flexed hip posture could be driving lower extremity kinematic changes toward increased coordination between joints and increased knee and ankle motions. Walking balance changes were also detected through increased COM motion (lateral range of motion and velocity) in the lateral directions. However, there was little correlation between kinematic and balance changes (r² < 0.4). Strong correlations were only observed when all kinematics (including those that don't ubiquitously change during pregnancy) were used in the regression model (r² > 0.7).

SIGNIFICANCE

Our findings suggest that walking balance control is not altered by a common kinematic change between all pregnant women. While increased lateral center of mass motion should be expected with pregnancy, the kinematics leading to this increase may be person-specific. The cause of dynamic imbalance in each pregnant women (physiological, mechanical, and neurocognitive) may play an important role in determining the kinematic means by which lateral center of mass motion increases.

Refractive status during pregnancy in the United States: results from NHANES 2005-2008

PURPOSE

Anecdotal reports of refractive changes in pregnancy are familiar to optometrists and ophthalmologists. Refractive stability during pregnancy has implications in both prescribing of refractive correction and candidacy for refractive surgery. This study aims to examine refractive status in a nationally representative sample of US pregnant women.

METHODS

The National Health and Nutrition Examination Survey (NHANES) is a weighted, stratified, cross-sectional survey of the US population conducted every 2 years. During 2005-2006 and 2007-2008, the exam included multiple ophthalmic tests including refraction, keratometry, and lensometry. Female participants aged 20-44 years with available vision examination data were included in the study. Subjects were excluded if best obtainable visual acuity was worse than 20/40 or there was prior history of cataract or refractive surgery. The primary outcome was defined as refractive change stratified by trimester of pregnancy.

RESULTS

301 pregnant women were matched with 301 nonpregnant controls based on age, ethnicity, and education. There was no difference in refractive error between pregnant women and matched nonpregnant controls (all p > 0.99). For the refractive change analysis, a subgroup of 60 pregnant subjects with glasses at presentation was matched to 60 nonpregnant controls. Multivariate regression showed a significant increase in refractive change versus prior to glasses prescription by trimester of pregnancy (p = 0.02), though this change was not in a specific direction (i.e., no significant shift toward either myopia or hyperopia).

CONCLUSIONS

Pregnant women have greater refractive difference from prior spectacle prescription later in pregnancy, but the direction of this change is variable and not significant. This finding may reflect a longer time to last glasses prescription later in pregnancy, given concerns that refractive error fluctuates in pregnancy. Additional longitudinal studies are needed to better characterize the effects of pregnancy on refractive status.

Ocular vascular changes during pregnancy: an optical coherence tomography angiography study

BACKGROUND

Pregnancy is a period presenting with many physiological adaptation mechanisms. One of the structures in which these mechanisms are observed is ocular tissues. The cornea, lacrimal and meibomian glands, and chorioretinal complex are all among the structures affected by changes during pregnancy. In this study we aimed to evaluate the macular and optic disc vessel density (VD) changes by Optical Coherence Tomography Angiography (OCTA) imaging in pregnancy.

METHODS

A total of 248 eyes from 124 pregnant women and 80 eyes from 40 healthy control women were involved. Vessel densities of macula were evaluated for superficial capillary plexus (SCP) and deep capillary plexus (DCP) in whole macula, foveal, parafoveal and perifoveal region. Peripapillary and whole optic disc VDs were also evaluated. Vessel densities of macula and optic disc were compared between control individuals and pregnant women. Vessel densities in different trimesters were also evaluated.

RESULTS

Modest but significant differences in VDs of whole macula of SCP and DCP were observed in pregnancy group. Additionally, perifoveal and parafoveal region of SCP, whole disc and radial peripapillary capillary VD were significantly higher in pregnancy group. There was no correlation between VD ratios of macula and optic disc and pregnancy weeks and trimesters.

CONCLUSIONS

This is the first study focusing on the OCTA parameters in pregnant individuals. These findings suggest that physiological changes during pregnancy are not limited to the cornea, eyelids and the choroid but also to the retinal and optic disc vasculature.

Should I Get LASIK If I'm Breastfeeding?

Changes in keratometric values and refraction can occur during pregnancy. For this reason, changing a patient's refractive prescription or undergoing corneal refractive surgery is not recommended during pregnancy. However, the extent to which these corneal changes persist during lactation is not as well reported. Pregnancy and lactation lead to hormonal changes that affect the corneal structure. LASIK, or other types of refractive surgery, is not recommended until all of the following conditions are met: cessation of lactation, the return of regular menses, and a return to pre-pregnancy refraction. Additionally, patients should be cautioned that refractive regression may occur if they become pregnant within 1 year of LASIK. FUNDING: Research to Prevent Blindness, NY, USA.

Sex Hormones and Optic Nerve Disorders: A Review

Aim: This review article presents a comprehensive overview of the literature on sex hormones (estrogens, androgens, progesterone) and optic nerve disorders, with a discussion of the implications for therapy and prevention.

Methods: Epidemiological, pre-clinical and clinical studies were reviewed.

Results: Analysis of the biological basis for a relationship between eye diseases and sex hormones showed that some types of hormones can exert a protective effect either directly on the retina and optic nerve or indirectly by modulating ocular blood flow. For example, it seems that estrogen exposure has a protective effect against glaucoma, whereas its deficit may lead to early onset of the disease. If further studies confirm the data in the literature, estrogen therapy, because of its antioxidant action, may be effective in the treatment of Leber's hereditary optic neuropathy, whereas, in the light of current studies, there does not seem to be an influence of estrogen on non-arteritic anterior ischemic optic neuritis (NAION).

Conclusions: Although there is some evidence that in some optic nerve pathologies the sex hormones seem to play an important role there are still too few studies providing evidence for its wider use in clinical practice.

Visual acuity and refractive changes among pregnant women in Enugu, Southeast Nigeria

INTRODUCTION

Pregnancy has been associated with changes in the eye which could be physiological, pathological, or exacerbation of pre-existing ocular conditions. Visual acuity (VA) and refractive error (RE) changes are part of the physiological changes that may occur during pregnancy.

OBJECTIVE

The objective of the present study was to investigate changes in VA and RE across two different trimesters and six weeks postpartum among pregnant women in Enugu, southeast, Nigeria.

MATERIALS AND METHODS

A longitudinal study was adopted and pregnant women in their second trimester attending antenatal clinic at University of Nigeria Teaching Hospital, Ituku-Ozalla, Enugu were consecutively recruited. A questionnaire was used to obtain information on their sociodemographic and clinical characteristics. Visual acuity was measured and refractive error monitored in second and third trimesters and 6 weeks after delivery.

RESULTS

The mean age of women was 30.81 (±5.49) years and a majority of them were civil servants. There was a worsening of VA for distance in more women in the third trimesters compared to the second trimester. There was no significant change in VA for near throughout the study period. There was an increased myopic shift in more pregnant women during the third trimester (40; 40.0%) compared to second trimester (36; 36.0%). The most common refractive error found among the women was simple myopia. These changes resolved six weeks postpartum.

CONCLUSION

Pregnancy worsened VA for distance and the most common RE in pregnant women was simple myopia. However, these changes resolved during the postpartum period.

Macular choroidal thickness in highly myopic women during pregnancy and postpartum: a longitudinal study

Background

High myopia, a cause of serious visual impairment, is a significant global public health concern. We investigate longitudinal changes in macular choroidal thickness (CT) during pregnancy and 6-months postpartum in women with high myopia (HM).

Methods

A prospective longitudinal study was conducted in HM-pregnant women during the course of pregnancy (n = 42 eyes, 42 patients) and 6 months postpartum (n = 40 eyes, 40 patients, two cases lost).Macular CT was measured via enhanced-depth imaging (EDI)-optical coherence tomography (OCT) (EDI-OCT). Intraocular pressure (IOP), axial length (AL), refractive error, mean arterial pressure (MAP), mean ocular perfusion pressure (MOPP), and body mass index (BMI) were also measured.

Results

Macular CTs of HM pregnant women (214.3 ± 52.3 μm) had increased significantly during the third trimester of pregnancy compared with postpartum women (192.7 ± 51.9 μm, p = 0.014). No significant differences in AL, refractive error, or MAP were found between pregnant and postpartum groups (p > 0.05 for all parameters).During pregnancy, macular CT was negatively correlated with AL (first trimester: p = 0.010; second trimester: p = 0.013; and third trimester: p = 0.008) and positively correlated with refractive error (first trimester: p = 0.038; second trimester: p = 0.024; and third trimester: p = 0.010). No correlations between macular CT and age, IOP, MOPP, MAP, or BMI were found.

Conclusions

Our study revealed the presence of a significantly thicker choroid during the third trimester of pregnancy compared with 6-mo postpartum in HM women. Macular CT positively correlated with refractive error and negatively correlated with AL during pregnancy, but did not correlate with gestational age, MOPP, IOP, MAP, or BMI.

Ocular changes during pregnancy

Purpose

To summarize available literature on physiologic and pathologic ocular changes during pregnancy.

Methods

Narrative review of literature.

Results

Ocular changes occur commonly during pregnancy. Although most of these are benign physiologic responses to the metabolic, hormonal, and immunologic modifications to adopt the gestational product, there is some serious pathology that may develop, exacerbate, or even resolve over the course of pregnancy which requires prompt diagnosis and management. The pathological eye conditions can be classified into preexisting pathologies and emerging ocular diseases. Regardless of the different mechanisms by which these ocular changes occur, the key point is the establishment of an effective perinatal screening program to monitor the new development or successive progression of these ocular abnormalities. Irrespective of the visual health status of the pregnant women, regular perinatal eye examination should be scheduled in order to assure continuous surveillance of healthy eyes. Treatment of pathologic ocular conditions or functionally disturbing benign changes relies on an appropriate patient selection.

Conclusions

Discriminating pathological eye disease from physiologic ocular changes is important in order to establish an individualized treatment or preventive plan and constitutes the mainstay of obstetric ophthalmology. This individualized approach should always weigh the ocular benefits of treatment to the mother against the potential harms to the fetus.

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

PURPOSE

To identify biomechanical and topographic changes of the cornea during pregnancy and the postpartum period and its association to hormonal changes.

DESIGN

Prospective single-center observational cohort study.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Enhanced Depth Imaging Optical Coherence Tomography: A New Way Measuring Choroidal Thickness in Pregnant Women

The body changes markedly during pregnancy; each system behaves differently from a nonpregnant state. As the eyes are the only windows to see directly what is going on in the internal environment, more and more researches have been done to explain the association between ocular changes and the physiological and pathological changes during pregnancy. The choroid is one of the critical parts of the eye, providing nutrition. And abnormal choroid may result in ocular dysfunction and visual problems. As the optical coherence tomography develops, a rapid, direct, noninvasive, and nontoxic way is available to obtain the choroid situation of pregnant women, which may explain the mechanism of pregnancy-related eye diseases. This review would summarize relevant original articles published from January 1, 2008 to December 1, 2016 to assess the changes of choroidal thickness (CT) with enhanced depth imaging optical coherence tomography (EDI-OCT) during pregnancy. And the relationship between choroidal thickness changes and pregnancy remains uncertain. To our knowledge, this is the first review of EDI-OCT in assessing the choroidal thickness of the pregnant women.

Effect of pregnancy in myopia progression: the SUN cohort

PurposePrevious studies have suggested that pregnancy may induce myopia progression. However, no longitudinal study with a large sample size and long-term follow-up has assessed this association. Our objective was to investigate whether pregnancy was related to mid- or long-term myopic refraction changes.Patients and methodsA prospective study was conducted in a Mediterranean cohort. The study included 10 401 women (20-50 years old) from the SUN Project. SUN project is a multipurpose, prospective, and dynamic cohort of university graduates conducted in Spain. The recruitment of participants started in 1999 and it is permanently open. All participants in this cohort had university studies. Participants were followed up for a period of up to 14 years, and pregnancy and refractive changes were assessed through baseline and biennial questionnaires. Pregnancies and myopia were repeatedly assessed in each biennial follow-up questionnaire during a total of 14 years of follow-up.ResultsPregnancy was inversely associated with the risk of myopia development or progression during each of the 2 years periods, with fully adjusted hazard ratio=0.61; (95% confidence interval=0.49-0.75) after adjusting for known potential confounders.ConclusionTo our knowledge this is the first large-longitudinal assessment in young adult women, showing that pregnancy is inversely associated with myopia development or progression. Further studies are needed to confirm these epidemiological findings.