Evaluation of anterior segment parameters during and after pregnancy

Evaluation of anterior segment parameters between pregnancy trimesters and postpartum with pentacam scheimflug ımaging: a prospective study

PURPOSE

To evaluate the effect of pregnancy on the anterior chamber, corneal parameter, and intraocular pressure measurements; and compare the results between trimesters, postpartum and non-pregnant healthy age-matched women.

METHODS

This prospective study included 41 pregnant women and 53 non-pregnant women. Four measurements were taken from the pregnant women, in each trimester and postpartum third month, and once from the control group. Of the individuals included in the study, anterior chamber depth (ACD), anterior chamber volume (ACV), K1 (flat keratometry), K2 (steep keratometry), Kmean (mean value of K1 and K2), anterior chamber angle (ACA), central corneal thickness (CCT), thinnest corneal thickness (TCT), astigmatism value (AST), corneal volume (CV), biometry, axial length (AL), spherical equivalent (SFEQ), intraocular lens power (ILP), VA (visual acuity) datas were recorded.

RESULTS

We observed a statistically significant decrease in K2, CCT, ACD, AL and CV in the postpartum period (p = 0.025, p < 0.001, p = 0.029, p = 0.005, p = 0.004 respectively) and a statistically significant increase in ACV, CCT, and TCT as the gestational week progressed in the pregnant group (p = 0.007, p < 0.001, p = 0.025, respectively). A statistically significant decrease in IOP towards to the third trimester, and an increase in the postpartum period was observed (p < 0.001). We did not observe statistically significant changes in K1, Kmean, AST, ACA, VA, ILP, and SFEQ values.

CONCLUSION

It is important to investigate the physiological changes that may occur during pregnancy, distinguish them from pathological changes, and avoid unnecessary treatment. We consider that it's also important to guide the timing of anterior segment surgeries such as cataract and refractive surgery and to prescribe glasses/contact lenses.

Corneal Fourier and Belin-Ambrósio Enhanced Ectasia Analysis in Healthy 4-Year-Old White Children

PURPOSE

The aim of this study was to provide normative databases of Fourier analysis (FA) and Belin-Ambrósio enhanced ectasia display (BAD) in healthy White 4-year-old emmetropic children.

METHODS

FA parameters analyzed were spherical component (SRmin), spherical eccentricity (SEcc), maximal decentration (MD), regular astigmatism at the center (Astigm. C) and periphery (Astigm. P), and irregularity (I). The parameters obtained by BAD included summary indicator BAD D, anterior corneal curvature (K1 and K2, D), maximal keratometry (Kmax, D), maximal Ambrósio relational thinnest (ART max), and pachymetric and BAD indices.

RESULTS

Eighty-nine eyes of eighty-nine 4-year-old children were included. The mean values of FA parameters were the following: SRmin 7.77, SEcc 0.600, MD 0.160, Astigm. C 0.070, Astigm. P 0.050, and I 0.019. The mean K1 and K2 in our study group were 42.92 ± 1.29 D and 43.75 ± 1.41 D, with the mean BAD D value 0.42 ± 0.67. The mean PPI min 0.629 ± 0.117, PPI max 1.059 ± 0.155, PPI avg 0.847 ± 0.103, Kmax 44.10 ± 1.39, and median of ART max 515.0 were recorded. No statistically significant differences between male and female sex in any of FA or BAD parameters were found.

CONCLUSIONS

This is the first study providing large normative data on FA and BAD in 4-year-old White emmetropic children. We proposed a cutoff D value for early ectasia and clinical keratoconus in 4-year-old children.

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.

The effect of pregnancy on meibomian gland, tear film, cornea and anterior segment parameters

AIM

In this prospective study, we aimed to examine the effect of physiological and pathological changes that occur during pregnancy in regard to Meibomian Gland (MG) structure, tear film, cornea and anterior segment parameters.

METHODS

The following groups were compared: 49 eyes of 49 pregnant women at 16-20 weeks of pregnancy (P16 Group), 46 eyes of 46 pregnant women at 32-36 weeks of pregnancy (P32 Group) and 51 eyes of 51 participants who were not pregnant (P0 Group). The groups were compared in terms of the first break-up time (NIF-BUT) and average break-up time (NIAvg-BUT) values. Non-contact meibography and MG loss rates were also compared.

RESULTS

The groups were found to be compatible in terms of age (P=0.052). The mean NIF-BUT values in the P16, P32 and P0 groups were 4.7 ±2.7, 6 ±3 and 6.7 ±3.1 seconds, respectively (P=0.055). The mean MG loss rates for the upper lid in the P16, P32 and P0 groups were 35.3%±12.6, 33.4%±11.4 and 15.5%±5.4, respectively. The loss rates for the lower lid in the P16, P32 and P0 groups were found to be 40.5%±18.6, 40.5%± 14.4 and 20.1%±8.1, respectively (P=0.000, p=0.000). The mean anterior chamber value (ACV) was found in the P16, P32 and P0 groups with 160.8 ±31.8, 150.9 ±26.5 and 165.9 ±26.5 µm³, respectively (P=0.035).

CONCLUSION

MG loss was found to be higher in pregnant groups compared to the non-pregnant groups. We found minimal instability in the tear film of the pregnant groups. We believe that pregnant women should be followed closely in terms of ocular surface diseases.

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.

Pregnancy and the eye

PURPOSE OF REVIEW

The aim of this study was to summarize common eye changes that may occur during pregnancy, and how pregnancy may affect preexisting eye conditions such as glaucoma and diabetic retinopathy. Challenges and complexities surrounding the treatment of these eye conditions during pregnancy are also highlighted.

RECENT FINDINGS

Refractive changes are common and may persist in the postpartum in patients with keratoconus. Although new medical and surgical glaucoma treatments are available, their safety in pregnancy is unknown. Limited use of topical and systemic glaucoma therapies is recommended, with a preference for selective laser trabeculoplasty as first line treatment in appropriate cases. The impact of pregnancy on diabetic retinopathy remains unclear. Although anti-vascular endothelial growth factor agents are first-line treatment for sight-threatening diabetic retinopathy, their effect on the developing foetus remains unknown and are therefore best avoided in the first and second trimesters. Noninfectious uveitis tends to become less active during pregnancy, allowing the potential tapering of systemic therapy and the use of local topical or injected corticosteroid treatment for active disease as required.

SUMMARY

Significant changes can occur to the eye during pregnancy, wherein the optimal treatment for many ocular conditions remains uncertain, highlighting the need for further research to develop clear recommendations that best balance the need to preserve the mother's sight, and the health of the developing foetus. The need for preconception planning, and collaborative multidisciplinary care between the obstetrician, physician, ophthalmologist and paediatrician is paramount.

Progressive corneal ectatic disease in pregnancy

Pregnancy influences ocular changes which may exacerbate existing or develop new pathology. This review summarises the existing evidence on the association between pregnancy and progressive keratoconus or iatrogenic keratectasia. Ten online databases were searched systematically. Eligible studies were published in English and reported objective ophthalmic outcomes for women with evidence of (i) a new diagnosis of keratoconus, (ii) keratoconus progression or (iii) iatrogenic keratectasia following refractive surgery; during or within one year of pregnancy. Strength of evidence was assessed using the Oxford Centre for Evidence-Based Medicine levels of evidence. Seventeen articles have reported 33 peripartum women with new-onset or progressive ectasia, evident by signs of corneal hydrops or protrusion (n = 8); steepening on topography imaging (n = 20); a mean decline in best corrected visual acuity by +0.20 logMAR (95% CI -0.01 to +0.40, n = 23); a mean increase in maximum keratometry by 2.18 D (95% CI 1.44 to 2.91, n = 42); a mean decline in spherical equivalent refraction by -1.33 D (95% CI -1.73 to -0.93, n = 41); and a mean increase in astigmatism by -1.61 D (95% CI -2.46 to -0.75, n = 19). Pregnancy is associated with progressive ectasia in some women including those with previously stable keratoconus, or a history of laser-assisted in situ keratomileusis surgery or no history of corneal ectasia. This review highlights the heterogeneity in limited existing evidence, the need for a standardised definition of ectasia progression and further prospective studies for clinical guidelines. Closely monitoring women at risk may assist in early intervention with collagen cross-linking and prevent peripartum vision loss.

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.

The distribution of relaxin receptors in the anterior segment of primary open-angle glaucoma patients

Purpose:

Relaxin is a polypeptide hormone produced by the corpus luteum and the decidua in females and by the prostate in males. It has vasodilatory and antifibrotic effects. In the past, it has been reported that injection of relaxin hormone has caused a reduction in the intraocular pressure although its mechanism has not yet been fully understood and the expression of relaxin receptors has not yet been evident in the human eye. Therefore, the purpose of this current study was to examine the presence of relaxin receptors in the human eye anterior segment.

Methods:

This is an interventional non-randomized study. Patients with primary open-angle glaucoma who underwent trabeculectomy were recruited. During the surgery, a punch biopsy (including the cornea, sclera, trabecular meshwork, and Schlemm's canal) was taken and stained with hematoxylin-eosin, and immunohistochemistry staining for relaxin/insulin-like family peptide receptor 1 (RXFP1).

Results:

A positive staining was noted for RXFP1 in the inner uveal, corneoscleral, and cribriform meshwork and Schlemm's canal's endothelium. Negative staining for RXFP1 was noted in the cornea and sclera.

Conclusion:

RXFP1 is present in the anterior segment drainage system of the human eye. Therefore, this receptor may have an active role in regulating the outflow facility and in the reduction of intraocular pressure.

Evaluation of Anterior Segment Parameters During Pregnancy

PURPOSE

To evaluate the anterior segment changes of eye during pregnancy according to the trimesters and compare them with non-pregnant subjects.

MATERIALS AND METHODS

This prospective study included 90 pregnant women (1.trimester: 30, 2.trimester: 30, 3.trimester: 30 pregnants) and 30 non-pregnant women whose ages ranging from 20 to 40 years. Intraocular pressure (IOP) and keratometry values were measured. Corneal thickness (CT) measurements were performed from pupil center, corneal apex and thinnest point of cornea. In addition, anterior chamber volume (ACV), anterior chamber depth (ACD) and anterior chamber angles (ACA) were also measured.

RESULTS

All trimester groups (1, 2 and 3.trimester) were compared with non-pregnant women for all measured parameters. The mean IOP values were significantly lower in 2nd and 3rd trimesters (p˂0.05). The differences of keratometric and CT measurements were not statistically significant in pregnant women when compared with non-pregnant women (p > .05). ACV was significantly higher in 1st trimester (p˂0.05); the difference of ACV in 2nd and 3rd trimesters was not significant (p > .05). There was also no significant difference in ACD and ACA measurements in trimester groups when compared with non-pregnants (p > .05).

CONCLUSIONS

We found that IOP decreased in 2nd and 3rd trimesters, and ACV increased in 1st trimester of pregnancy when compared with non-pregnant women. If the physiological changes in pregnancy are well known, diseases that affect anterior segment such as glaucoma and corneal disorders will be managed more accurately.

Management of Glaucoma in Pregnancy

Management of glaucoma during pregnancy represents a challenge for the physician. Important disease and patients' health decisions begin even before conception and continue throughout pregnancy and breastfeeding. The data on this topic is limited due to ethical and legal constraints and challenges of conducting large, prospective, and randomized clinical trials on this patient population. Our review suggests that individually, intraocular pressure is lower in a pregnant woman when compared with a nonpregnant woman. Importantly, the medical management of glaucoma during pregnancy poses special challenges due to the possibility of adverse effects of medications on the fetus and newborn. Laser trabeculoplasty and traditional filtration surgery, and minimally invasive glaucoma surgery, represent nondrug management options. Thus, managing glaucoma in pregnancy is a delicate balance between treatment to prevent damage to the optic nerve in the mother and avoidance of interventions potentially harmful to the fetus. This literature review of published individual and population-based studies was performed to explore current knowledge and guidelines in the management of glaucoma in pregnancy.

Topical Estrogen Therapy for Hyperopia Correction in Vivo

Purpose

In vitro studies found that 17β-estradiol (estrogen) modulates corneal biomechanical properties and reduces tissue stiffness. Therefore we hypothesized that topical estrogen might affect the refractive properties of the cornea, inducing a myopic shift.

Methods

Twelve female New Zealand white rabbits 16 weeks old were used. The rabbits were randomly divided to either the treatment group receiving 1.5% (w/v) estrogen eye drops or a control group receiving vehicle only (n = 6 each group). Both groups were given drops (50 µL) to the right eye every 12 hours for 35 days. Ocular examination, pachymetry, intraocular pressure (IOP), keratometry, and refraction were evaluated at baseline and on a weekly basis.

Results

No significant differences were observed between the two groups at baseline in all outcome measures. Both groups displayed corneal flattening and a hyperopic shift. However, the change rate was slower in the treatment group. Repeated measurements analysis revealed a statistically significant difference in keratometry readings between groups (P = 0.034) with steeper keratometry by up to 0.6 diopters in the treatment group. The difference between the two groups diminished and became statistically insignificant after treatment cessation. No significant changes were observed in IOP and pachymetry throughout the study period. No side effects were observed in either group.

Conclusions

Estrogen eye drops induced a myopic shift in keratometry readings. These results suggest that corneal refractive power might be manipulated pharmacologically. Further studies on the physiology behind this change are warranted to facilitate a pathway for development of novel pharmacologic treatments to correct refractive errors.

Ocular Phenotype of Relaxin Gene Knockout (Rln-/-) Mice

Purpose: To test if relaxin deficiency affects ocular structure and function we investigated expression of relaxin (Rln) and RXFP receptors (Rxfp1, Rxfp2), and compared ocular phenotypes in relaxin gene knockout (Rln^-/- ) and wild type (Rln^+/+ ) mice. Materials and Methods: Rln, Rxfp1 and Rxfp2 mRNA expression was detected in ocular tissues of Rln+/+ mice using RT-PCR. The eyes of 11 Rln^-/- and 5 Rln^+/+ male mice were investigated. Corneal and retinal thickness was assessed using optical coherence tomography. Intraocular pressure was measured using a rebound tonometer. Retinal, choroidal and sclera morphology and thickness were evaluated histologically. Eyes were collected and fixed for immunofluorescence staining or used for RNA extraction to evaluate mRNA expression using real-time PCR. Results: Rln mRNA was expressed only in the retina, whereas Rxfp1 transcripts were detected in the retina, cornea and sclera/choroid. Rxfp2 was only present in the cornea. None of these genes were expressed in the lacrimal gland, eyelid or lens. Intraocular pressure was higher and central cornea of Rln^-/- mice was significantly thicker and had significantly larger endothelial cells and a lower endothelial cell density than Rln^+/+ mice. Immunohistochemistry demonstrated no significant difference in AQP3 and AQP5 staining in the cornea or other regions between wildtype and Rln^-/- mice. mRNA expression of Aqp4 was significantly higher in Rln^-/- than in Rln^+/+ corneas, whereas Col1a2, Mmp9, Timp1 and Timp2 were significantly decreased. Expression of Aqp1, Aqp4, Aqp5, Vim and Tjp1 was significantly decreased in Rln^-/- compared to Rln^+/+ uvea. No significant differences in these genes were detected in the retina. Retinal, choroidal and scleral thicknesses were not different and morphology appeared normal. Conclusion: The findings indicate that loss of Rln affects expression of several genes in the uvea and cornea and results in thicker corneas with altered endothelial cells. Many of the gene changes suggest alterations in extracellular matrix and fluid transport between cells.

Changes in corneal biomechanics during pregnancy in Chinese healthy female

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.

Intraocular pressure and tear production changes in pregnant women at term pregnancy and immediate post-partum: A pilot study

Aim:

To study the intraocular pressure (IOP) and tear production changes in uncomplicated pregnant women at term pregnancy and immediate postpartum.

Materials and methods:

The patients admitted in the Department of Obstetrics and Gynaecology for delivery were included in the study. A total of 106 participants who were at term uncomplicated pregnancy were selected according to the inclusion and exclusion criteria. They were subjected to type 1 Schirmer's testing and intraocular pressure measurement by Perkin's tonometer before and after delivery.

Result:

There was no significant pre- and postdelivery IOP difference between the different age groups (<30 and ≥30 years), mode of delivery, and parity. There was a statistically significant (P < 0.001) increase in mean tear production (Schirmer's test) after delivery, irrespective of age group, mode of delivery, and gravida status. However, no significant intergroup difference was observed.

Conclusion:

There was no significant change in IOP before and after delivery in uncomplicated pregnancies. However, a statistically significant increase in tear production was observed in the immediate postpartum period.

Modeling Changes in Corneal Parameters With Age: Implications for Corneal Disease Detection

PURPOSE

To apply computational methods to model normal age-related changes in corneal parameters and to establish their association with demographic factors, thereby providing a framework for improved detection of subclinical corneal ectasia (SCE).

DESIGN

Cross-sectional study.

METHODS

One hundred seventeen healthy participants were enrolled from Centre for Eye Health (Sydney, Australia). Corneal thickness (CT), front surface sagittal curvature (FSSC), and back surface sagittal curvature (BSSC) measurements were extracted from 57 corneal locations from 1 eye per participant using the Pentacam HR. Cluster analyses were performed to identify locations demonstrating similar variations with age. Age-related changes were modeled using polynomial regression with sliding window methods, and model accuracy was verified with Bland-Altman comparisons. Pearson correlations were applied to examine the impacts of demographic factors.

RESULTS

Concentric cluster patterns were observed for CT and FSSC but not for BSSC. Sliding window analyses were best fit with quartic and cubic regression models for CT and FSSC/BSSC, respectively. CT and FSSC sliding window models had narrower 95% limits of agreement compared with decade-based models (0.015 mm vs 0.017 mm and 0.14 mm vs 0.27 mm, respectively), but were wider for BSSC than decade-based models (0.73 mm vs 0.54 mm). Significant correlations were observed between CT and astigmatism (P = .02-.049) and FSSC and BSSC and gender (P = <.001-.049).

CONCLUSIONS

The developed models robustly described aging variations in CT and FSSC; however, other mechanisms appear to contribute to variations in BSSC. These findings and the identified correlations provide a framework that can be applied to future model development and establishment of normal databases to facilitate SCE detection.

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.

Relaxin 2 fails to lower intraocular pressure and to dilate retinal vessels in rats

PURPOSE

Recently, the vasodilator relaxin 2 has been introduced as a treatment for acute heart failure. However, its role on vessels of the eye and intraocular pressure (IOP) remains unclear though it has been hypothesized to induce a decrease IOP after intramuscular injection in humans. We aimed to test whether the hormone relaxin 2 lowers IOP and dilates retinal vessels in animals.

METHODS

The IOP of female Sprague-Dawley rats before and after application of relaxin 2 was measured using an Icare Tonolab device calibrated for rats. Recombinant human relaxin 2 in phosphate-buffered saline with 0.1% bovine serum albumin was either applied as eye drops (1000, 2000 or 3000 ng/ml), injected intravitreally (500 ng/ml) or intravenously (13.3 μg/kg body weight). Retinal vessel thickness was monitored using infrared fundus images compiled with optical coherence tomography (Heidelberg Engineering) before and several time points after application of relaxin 2.

RESULTS

Neither topical nor intravitreous or intravenous application of relaxin 2 lowered the IOP or changed the arterial or venous vessel diameter after 1 or 3 h after application.

DISCUSSION

Now that relaxin 2 is more easily available, the hormone came again into focus as a potential glaucoma therapeutic. However, our study in rats could not support the hypothesis that relaxin 2 lowers IOP or dilates retinal vessels.

Ocular Changes During Pregnancy

Pregnancy is needed for the perpetuation of the human species, and it leads to physiological adaptations of the various maternal organs and systems. The eye, although a closed space, also undergoes some modifications, most of which are relatively innocuous, but they may occasionally become pathological. For women, pregnancy is a susceptibility period; however, for many obstetricians, their knowledge of the ocular changes that occur during pregnancy tends to be limited. For this reason, this is a important area of study as is necessary the development of guidelines to approach those changes. Of equal importance are the knowledge of the possible therapies for ophthalmological problems in this period and the evaluation of the mode of delivery in particular conditions. For this article, an extensive review of the literature was performed, and a summary of the findings is presented.

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.

Changes in intraocular pressure and central corneal thickness during pregnancy: a systematic review and Meta-analysis

AIM

To conduct a Meta-analysis for investigating the variations in intraocular pressure (IOP) and central corneal thickness (CCT) during normal pregnancy.

METHODS

We searched for clinical trials published up to November 2015 without language or region restrictions in PubMed, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials, Ovid, EBSCO, Elsevier, the Chinese Biomedicine Database, WanFang, CNKI, CQVIP and Google Scholar. Studies of the ocular changes observed in pregnant women were selected. The main outcomes were assessed by changes in IOP and CCT.

RESULTS

Fifteen studies were included. In subgroup analyses, IOP was significantly decreased during the second MD=-1.53, 95%CI (-2.19, -0.87); P<0.00001, and third MD=-2.91, 95%CI (-3.74, -2.08); P<0.00001 trimesters of pregnancy. CCT was increased during the second MD=10.12, 95%CI (2.01, 18.22); P=0.01, trimester of pregnancy; moreover, during the third trimester of pregnancy, the CCT displayed an increasing trend, but the difference was not significant MD=5.98, 95%CI (-1.11, 13.07); P=0.1.

CONCLUSION

A decrease in IOP is accompanied by an increase in CCT in the second and third trimesters of a normal pregnancy in women.

Anterior, posterior and biomechanical parameters of cornea during pregnancy in healthy eyes: a cohort study

BACKGROUND

To investigate the effect of pregnancy on anterior, posterior and biomechanical corneal parameters of healthy eyes.

METHOD

In this prospective cohort study, 70 pregnant participants with clinically healthy eyes underwent corneal topographic imaging evaluation by Pentacam and biomechanical assessment by Ocular Response Analyzer (ORA) before pregnancy, at the third trimester of pregnancy (34th week of pregnancy) and 12 months after delivery. The same number of age-matched non-pregnant females was evaluated at the corresponding appointments as the control group.

RESULTS

Assessment of the tomographic, topographic and ORA measurements before pregnancy, at the third trimester of pregnancy and 12 months post partum revealed no statistically significant changes in anterior and posterior corneal flat, steep and mean keratometry, anterior and posterior elevation measurements, central and thinnest corneal thickness, corneal hysteresis, corneal resistance factor and intraocular pressure measurements (p>0.05, repeated measures analysis of variance (ANOVA)). All of the study parameters returned to their baseline levels 1 year after delivery. The ophthalmic parameters of the non-pregnant group remained significantly unchanged during the study period (p>0.05, all comparisons, repeated measures ANOVA). Moreover, no statistically significant differences were found between pregnant and non-pregnant groups in the second (34th week of pregnancy) and third (post partum) appointments (p>0.05, all comparisons, one-way ANOVA).

CONCLUSION

Our findings may suggest a physiological nature for ocular changes during pregnancy that these changes return to baseline values after delivery. The differences between tomographic, topographic and biomechanical corneal parameters before pregnancy, during pregnancy and post partum were not statistically or clinically significant.

A survey of ophthalmologists and gynecologists regarding termination of pregnancy and choice of delivery mode in the presence of eye diseases

PURPOSE

To evaluate and compare the attitudes of ophthalmologists and gynecologists in suggesting appropriate approach to pregnancy in different ocular conditions.

METHODS

Specialty-specific questionnaires on delivery mode and abortion indications for ophthalmic patients (refractive, vascular, oncologic, retinal, glaucoma, postoperation, posttrauma, and infectious) were designed and distributed among physician staff of Farabi Eye Hospital and Yas Women Hospital in Tehran. Attitudes and preferences of the ophthalmologists and gynecologists were quantified and compared.

RESULTS

Participants were 29 ophthalmologists and 19 gynecologists. Their mean age was 49.73 ± 7.57 and 46.79 ± 1.36 years, respectively. More than 50-70% ophthalmologists were in favor of normal vaginal delivery (NVD) in all ocular diseases. All gynecologists (100%) expressed their need for an ophthalmologist's opinion for decision-making. Ophthalmologists' top choices for conditions potentially requiring a caesarean section were corneal transplants (34.5%), high myopia (23%), retinal detachment (29%), and orbital tumors (34.5%), while two gynecologists recommended abortion in the presence of intraocular and orbital tumors and retinal detachment. In the case of a history of refractive surgery, orbital tumor and intraocular tumor, ophthalmologists recommend NVD over caesarean section twice as much as their gynecologist peers. For history of retinal detachment, glaucoma, retinal vascular accident and intraocular hemorrhage, no single gynecologist recommend NVD. The corresponding figure for ophthalmologist-recommended NVD were 67, 84, 72, and 81%.

CONCLUSIONS

There is extreme inconsistency among ophthalmologists and gynecologists in managing ophthalmic-obstetric scenarios, especially for caesarean section indications. Clinical guideline development and consultation for decision-making in challenging cases are recommended.

Topographic, tomographic and biomechanical corneal changes during pregnancy in patients with keratoconus: a cohort study

PURPOSE

This study aimed at evaluating the effect of pregnancy on topographic, tomographic and biomechanical parameters of patients with keratoconus (KC) in comparison with non-pregnant patients with KC.

METHOD

In a cohort study, patients with KC, whose disease was stable for at least 2 years, were evaluated before pregnancy, at their third trimester of pregnancy (34th week of pregnancy) and 6 months after pregnancy. As the control group, an equivalent number of age- and severity-matched non-pregnant female patients with KC were evaluated at the corresponding times. All subjects were evaluated with respect to central and thinnest corneal thickness (CCT and TCT), keratometry values, and maximum anterior and posterior elevation measurements (AE and PE) by Pentacam. Furthermore, corneal biomechanical properties including corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using the ocular response analyser.

RESULTS

Twenty-two eyes of 11 patients were equally enrolled in each group. The results revealed that there was a statistically significant difference between the means of all measurements during the course of study (p < 0.001, repeated measures analysis of variance). The values of CCT, TCT, CH, CRF, IOPg and IOPcc were significantly decreased; however, keratometry values, AE, PE and refraction measurements were significantly increased during the study period (p < 0.001). In contrast, no significant differences were observed regarding the study variables in the control group (p > 0.05). According to the Amsler-Krumeich classification, severity of KC increased during the pregnancy and postpregnancy periods (p = 0.038).

CONCLUSION

The obtained results revealed that KC progressed during the pregnancy period and continued to the post-partum period, indicating that pregnancy may be a risk factor for KC progression. Patients with KC, who intend to become pregnant, may consider corneal cross-linking treatment in an attempt to stop KC progression.

Changes in choroidal thickness during pregnancy detected by enhanced depth imaging optical coherence tomography

AIM

To compare the choroidal thickness measurements of healthy pregnant women obtained in the first trimester with measurements obtained in the third trimester using enhanced depth imaging optical coherence tomography (OCT).

METHODS

54 eyes of 27 healthy pregnant women and 50 eyes of 25 age matched healthy women were enrolled in this observational, cross-sectional study. The pregnant women underwent two OCT scans, one in the first trimester at gestational weeks 6-8, and the other during the third trimester at gestational weeks 32-37; the control group had OCT scanning during the follicular phase of the menstrual cycle, using the enhanced depth imaging mode. Choroidal thicknesses were measured at the fovea, at three locations nasal, and at three locations temporal to the fovea at 500 μm intervals.

RESULTS

The choroidal thickness measurements obtained in the third trimester were significantly decreased in all measured points in both eyes compared to the measurements obtained in the first trimester (p<0.05). At the fovea, the mean (±SD) choroidal thickness measured in the first trimester was 349.22±82.11 μm in the right eyes and 341.30±85.22 μm in the left eyes, which decreased to 333.56±76.61 μm in the right eyes (p=0.014) and 326.93±75.84 μm in the left eyes (p=0.024) in the third trimester. Although not statistically significant, choroidal thicknesses of the control group were less than the choroidal thicknesses of the pregnant women (p>0.05).

CONCLUSIONS

Choroidal thickness was found to be significantly decreased in healthy pregnant women during the third trimester compared to the first trimester. This finding can provide valuable information when interpreting pregnancy related ocular disorders.