Maternal corneal thickness during pregnancy

Expression of Hormones' Receptors in Human Corneal Endothelium from Fuchs' Dystrophy: A Possible Gender' Association

Background: Age and sex are the most significant risk of factors for advanced Fuchs dystrophy. Nevertheless, few data are available on the hormone's receptor pattern expressed in adult and advanced fuchs endothelial corneal dystrophy (FECD). We investigated the impact of gender, growth factors and extracellular matrix (ECM) regulatory proteins expressed by the dystrophic endothelia. Methods: Ten dystrophic endothelial tissues and 10 normal endothelial sheets (corneoscleral specimens; Eye Bank) were used for this characterization study. Hormones' receptors (ERα, AR, PR, SHBG), few growth factors (VEGFA, βNGF, TGFβ1), some ECM regulators (MMP1, MMP7) and few inflammatory cytokines (IFNγ, IL10) were analyzed by real-time RT-PCR. Results: ERα transcripts were significantly increased, AR and SHBG transcripts were decreased in Fuchs endothelia from female patients, and no changes were detected for PR transcripts. VEGFA, βNGF and TGFβ1 transcripts were upregulated in Fuchs' endothelia, but not significantly linked to gender. High MMP1 and low MMP7 transcripts' expression were detected in Fuchs' specimens, mainly in males than females. An increased IFNγ (Th1) transcript expression was observed in females than males, and a trend to increase for IL10 (Th2) transcripts was detected in males than females. Conclusions: Our findings clearly indicate that hormone receptors, growth factors and matrix mediators as well as a Th1 pathway are predominant in Fuchs' dystrophy, displaying a pattern of expression specific for the female phenotype. The differential expression of hormones' receptors and the Th1/Th2 ratio might prompt to new theories to be tested in vitro and in vivo models, such as the use of hormonal substitute for counteracting this endothelial cell lost.

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.

The Effect of Hyperemesis Gravidarum on Macular Thickness, Corneal Thickness, and Intraocular Pressure in Pregnancy

AIM

Physiological changes in intraocular pressure as well as in the cornea and macula may occur during pregnancy. Therefore, we decided to investigate the effect of hyperemesis gravidarum on macular thickness, corneal thickness and intraocular pressure (IOP).

MATERIAL AND METHODS

A total of 110 people, 55 of whom were diagnosed with hyperemesis gravidarum and 55 of whom were in the control group, were included in the study. The inclusion criteria for the study were as follows: first trimester (8-14 weeks of gestation) pregnancy with positive fetal heartbeat and no history of systemic disease, no continuous use of medication, diagnosis of hyperemesis gravidarum (ketonuria and weight loss of more than 3 kilograms or 5% of body weight), body mass index (BMI) within normal limits, age between 18 and 40, no alcohol use or smoking.

RESULTS

In the HG group compared to the control group, there was a difference between the CCT values of both the right and left eyes (p<0.01). There was a difference in both right and left IOP values in patients in the HG group compared to the control group (p<0.05), and there was no correlation between ketonuria scores and right and left eye CCT values, right and left eye macular thickness, and right and left eye pressure in patients diagnosed with HG (p>0.05).

CONCLUSION

In hyperemesis gravidarum, changes occur in IOP, corneal thickness, and macular thickness. In ophthalmic examinations in the pregestational period, especially for women with systemic disease, it may be important for clinicians to take the necessary precautions in this regard.

Corneal biomechanics and diagnostics: a review

PURPOSE

Corneal biomechanics is an emerging field and the interest into physical and biological interrelations in the anterior part of the eye has significantly increased during the past years. There are many factors that determine corneal biomechanics such as hormonal fluctuations, hydration and environmental factors. Other factors that can affect the corneas are the age, the intraocular pressure and the central corneal thickness. The purpose of this review is to evaluate the factors affecting corneal biomechanics and the recent advancements in non-destructive, in vivo measurement techniques for early detection and improved management of corneal diseases.

METHODS

Until recently, corneal biomechanics could not be directly assessed in humans and were instead inferred from geometrical cornea analysis and ex vivo biomechanical testing. The current research has made strides in studying and creating non-destructive and contactless techniques to measure the biomechanical properties of the cornea in vivo.

RESULTS

Research has indicated that altered corneal biomechanics contribute to diseases such as keratoconus and glaucoma. The identification of pathological corneas through the new measurement techniques is imperative for preventing postoperative complications.

CONCLUSIONS

Identification of pathological corneas is crucial for the prevention of postoperative complications. Therefore, a better understanding of corneal biomechanics will lead to earlier diagnosis of ectatic disorders, improve current refractive surgeries and allow for a better postoperative treatment.

Estrogen dysregulation, intraocular pressure, and glaucoma risk

Characterized by optic nerve atrophy due to retinal ganglion cell (RGC) death, glaucoma is the leading cause of irreversible blindness worldwide. Of the major risk factors for glaucoma (age, ocular hypertension, and genetics), only elevated intraocular pressure (IOP) is modifiable, which is largely regulated by aqueous humor outflow through the trabecular meshwork. Glucocorticoids such as dexamethasone have long been known to elevate IOP and lead to glaucoma. However, several recent studies have reported that steroid hormone estrogen levels inversely correlate with glaucoma risk, and that variants in estrogen signaling genes have been associated with glaucoma. As a result, estrogen dysregulation may contribute to glaucoma pathogenesis, and estrogen signaling may protect against glaucoma. The mechanism for estrogen-related protection against glaucoma is not completely understood but likely involves both regulation of IOP homeostasis and neuroprotection of RGCs. Based upon its known activities, estrogen signaling may promote IOP homeostasis by affecting extracellular matrix turnover, focal adhesion assembly, actin stress fiber formation, mechanosensation, and nitric oxide production. In addition, estrogen receptors in the RGCs may mediate neuroprotective functions. As a result, the estrogen signaling pathway may offer a therapeutic target for both IOP control and neuroprotection. This review examines the evidence for a relationship between estrogen and IOP and explores the possible mechanisms by which estrogen maintains IOP homeostasis.

Trabeculectomy in first trimester of pregnancy: A case report

PURPOSE

Glaucoma management in pregnancy is a challenging task for the ophthalmologist. With limited studies due to ethical concerns, the exact management protocols are not well established. Surgery has been mentioned as an option in 2nd trimester and is avoided in 1st trimester due to the detrimental effect on organogenesis of fetus and the harmful effects of anaesthesia.

METHODS

A 26 year old woman with advanced glaucomatous damage underwent trabeculectomy without antifibrotic agent in first trimester of pregnancy.

RESULTS

The intraocular pressures (IOP) were well controlled during pregnancy with no need of addiitional antiglaucoma medications. She delivered a healthy baby at term with no congenital abnormality.

CONCLUSION

Trabeculectomy without antifibrotic agents can be done in first trimester of pregnancy in cases where IOP cannot be controlled with topical antiglaucoma drugs that are considered safe during this period. This is the first report in literature on trabeculectomy in first trimester of pregnancy.

Laser in situ keratomileusis and surface ablation in pregnancy

PURPOSE

Although corneal refractive surgery is contraindicated during pregnancy, some patients are unaware that they are pregnant when they undergo surgery. Our objectives were to determine the functional outcomes of corneal refractive surgery during pregnancy and to compare the results with those of nonpregnant women.

METHODS

We performed a multicenter, retrospective, interventional case series review of patients who were pregnant and who underwent laser in situ keratomileusis (LASIK) or surface ablation (photorefractive keratectomy, PRK) from September 11, 2002 to December 12, 2020 (group 1, n=82 eyes). Patients were included consecutively. Findings were compared with those of nonpregnant women (group 2, n=164 eyes). Functional (visual and refractive) outcomes are described. Follow-up was at least 550 days (control group, median [IQR], 990 days [715-1496]; study group, 895 days [709-1310]). The setting was Clínica Baviera, Spain, (AIER Eye Hospital Group).

RESULTS

A statistically significant difference was found between the groups in terms of efficacy index (EI). No complications of pregnancy or labor were reported. Similarly, a search of medical records revealed no adverse effects in the infants.

CONCLUSIONS

To the best of our knowledge, this is the first case series on pregnancy and refractive surgery. We do not recommend performing LASIK or surface ablation on pregnant women. Our objective in the present study was to present relevant scientific data obtained from women who underwent refractive surgery while unaware that they were pregnant.

Ocular findings in central precocious puberty

PURPOSE

To evaluate ocular findings in central precocious puberty (PP).

METHODS

This prospective study included 38 children with PP and 34 healthy control children. All participants were evaluated in terms of refractive error, axial length (AL), and anterior segment parameters, including keratometry (K), corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV), and iridocorneal angle (ICA). Central macular thickness (CMT), retinal nerve fiber layer (RNFL) thickness and central subfoveal choroidal thickness (ChT) were also analyzed. The correlation of these parameters with Tanner stage was also investigated in the PP group.

RESULTS

Compared with the control group, spherical refraction was less hyperopic (P = 0.017) and AL was significantly higher (P = 0.001) in the PP group. Spherical value and AL were significantly associated with the Tanner stage. None of the anterior segment parameters obtained by Pentacam was different in the PP group compared with controls. In PP cases, CMT and RNFL thicknesses in all sectors did not differ from controls. Subfoveal ChT was significantly higher in the PP group, regardless of Tanner stage (P < 0.001).

CONCLUSIONS

In our cohort of children with central PP, AL and ChT were higher than in children without PP.

Relationship between the sFlt-1/PlGF ratio and the optical coherence tomographic features of chorioretina in patients with preeclampsia

This study aimed to evaluate the correlation between ophthalmologic factors and the serologic indicator soluble fms-like tyrosine kinase 1 (sFlt-1): placental growth factor (PlGF) ratio in patients with preeclampsia using optical coherence tomography (OCT) and OCT angiography (OCT-A). A total of 52 pregnant patients (104 eyes) diagnosed with preeclampsia were recruited during their hospital stay. The associations between the sFlt-1/PlGF ratio and chorioretinal measurements, including the choroidal thickness (CT), foveal avascular zone, vascular density, and ganglion cell layer+ were evaluated. Central and nasal subfield CT of the left eye (p = 0.039; p = 0.010) and nasal subfield CT of the right eye (p = 0.042) were lower in the high sFlt-1/PlGF ratio group (≥38). Pearson’s correlation test showed a negative correlation between the sFlt-1/PlGF ratio and central subfield CT; however, this was not statistically significant (p = 0.648). Linear regression analysis revealed a significant association between the sFlt-1/PlGF ratio and central subfield CT (β coefficient, -6.66; p = 0.01) and between sFlt-1 and central subfield CT (β coefficient, -5.65; p = 0.00). Thus, an increase in the sFlt-1/PlGF ratio resulted in a decrease in central subfield CT.

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.

Influence of Sex on Neuroretinal Degeneration: Six-Month Follow-Up in Rats With Chronic Glaucoma

Purpose

To evaluate differences by sex in the neuroretina of rats with chronic glaucoma over 24 weeks of follow-up, and to assess by sex the influence on neurodegeneration of different methods of inducing ocular hypertension.

Methods

Forty-six Long-Evans rats-18 males and 28 females-with induced chronic glaucoma were analyzed. Glaucoma was achieved via 2 models: repeatedly sclerosing the episcleral veins (9 male/14 female) or by injecting poly(lactic-co-glycolic acid) microspheres measuring 20 to 10 µm (Ms20/10) into the anterior chamber (9 male/14 female). The IOP was measured weekly by tonometer; neuroretinal function was recorded by dark/light-adapted electroretinography at baseline and weeks 12 and 24; and structure was analyzed by optical coherence tomography using the retina posterior pole, retinal nerve fiber layer and ganglion cell layer protocols at baseline and weeks 8, 12, 18, and 24.

Results

Males showed statistically significant (P < 0.05) higher IOP in both chronic glaucoma models, and greater differences were found in the episcleral model at earlier stages. Males with episclerally induced glaucoma showed a statistically higher increase in retinal thickness in optical coherence tomography recordings than females and also when comparing Ms20/10 at 12 weeks. Males showed a higher percentage of retinal nerve fiber layer thickness loss in both models. Ganglion cell layer thickness loss was only detected in the Ms20/10 model. Males exhibited worse dark/light-adapted functionality in chronic glaucoma models, which worsened in the episcleral sclerosis model at 12 weeks, than females.

Conclusions

Female rats with chronic glaucoma experienced lower IOP and structural loss and better neuroretinal functionality than males. Sex and the ocular hypertension-inducing method influenced neuroretinal degeneration.

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.

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.

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.

Keratoconus progression associated with hormone replacement therapy

Purpose

To report a postmenopausal patient with keratoconus who experienced significant progression after using hormone replacement therapy.

Observations

A 51-year-old woman with previously stable keratoconus presented with acute disease progression following hormone replacement therapy in the context of prophylactic hysterectomy and bilateral ovariosalpingectomy. Over a 14-month period after starting hormone therapy, the steepest K increased from 63.7D to 71.5D in the right eye and from 65.8D to 78.1D in the left eye.

Conclusions

Hormone replacement therapy may amplify progression of keratoconus.

The physiologic and pathologic effects of pregnancy on the human visual system

Pregnancy is a normal state of physiological stress that induces significant changes in the human body, some of which can potentially affect the visual system. The pregnant state may exacerbate pre-existing ocular disorders (i.e. diabetic retinopathy or central serous retinopathy). Moreover, other systemic conditions related to pregnancy can induce ophthalmic disorders affecting the retina and the choroid, some of which are of acute nature. Increasing awareness and improving collaboration between ophthalmologists, obstetricians and internists can play a pivotal role in the management of complex conditions during pregnancy. Special attention should be given while prescribing medications or deciding about other diagnostic or therapeutic techniques. The purpose of this review is to summarise the physiologic and pathologic effects of pregnancy in the eyes, highlighting the most acute clinical entities that may be threatening for the vision or even the life of the mother and her baby.

Preliminary data for performance in hue ordering tests during pregnancy

The visual system of women changes during pregnancy. Few reports have addressed the effects of pregnancy on color vision. We aimed to compare the color vision of women in the first, second, and third trimesters of pregnancy. Fifty women were divided into first (n=10), second (n=10), third trimester pregnancy groups (n=10), and non-pregnant group (n=20). We used the Farnsworth D15 and Lanthony desaturated D15 (D15d) tests. The hue ordering quantified the amount of error (C-index) and the chromatic selectivity of the errors (S-index). Bland-Altman analysis was applied to the hue ordering data. No difference was found for Farnsworth D15 test results obtained from the pregnant groups and the non-pregnant group (P<0.0083). For the Lanthony D15 desaturated test, the third trimester pregnant group had higher C-index and S-index than non-pregnant women and first-trimester pregnant women (P<0.0083). The Bland-Altman analysis showed that the limits of agreement increased as pregnancy advanced, and the errors were biased to the D15d test. In this study, color vision was impaired during pregnancy. Color vision evaluation could be used as an indicator of the functional status of the central vision during pregnancy.

Estrogen- and Progesterone-Induced Variation in Corneal Parameters According to Hormonal Status

OBJECTIVES

To determine the effects of estrogen and progesterone on corneal thickness, curvature, and biomechanics in healthy corneas according to hormonal status.

METHODS

The study included four groups of females: group A (menstruating, not pregnant, not lactating, and not menopausal; n=100), group B (pregnant; n=50), group C (lactating; n=50), and group D (menopausal; n=50). Group A was subdivided according to age, as subgroup A15-25 (age 15-25 years) and subgroup A>25 (age >25 years). Blood estradiol and progesterone levels were measured in each participant. All the participants underwent a full ophthalmologic examination, including corneal thickness and corneal topography measurement, and evaluation of corneal biomechanical properties.

RESULTS

The corneal resistance factor and anterior corneal flat keratometry values were significantly higher in group D (P=0.040 and P=0.026, respectively) than in the other three groups. Posterior corneal steep keratometry values were significantly higher in subgroup A>25 during the preovulatory phase than ovulatory and postovulatory phases (P=0.012). In group B, there was a significant negative correlation between gestational week and intraocular pressure (IOP) (r=-0.322, P=0.024). Corneal volume was significantly higher during the early postpartum period than the late postpartum period in group C (P=0.028). Intraocular pressure, Goldman-correlated IOP, and corneal-compensated IOP differed significantly between the groups (P<0.05).

CONCLUSIONS

Blood levels of estrogen and progesterone were associated with variations in IOP, but estrogen and progesterone did not have a consistent effect on topographic parameters or biomechanical properties in healthy corneas.

Pathogenesis of Keratoconus: The intriguing therapeutic potential of Prolactin-inducible protein

Keratoconus (KC) is the most common ectatic corneal disease, with clinical findings that include discomfort, visual disturbance and possible blindness if left untreated. KC affects approximately 1:400 to 1:2000 people worldwide, including both males and females. The aetiology and onset of KC remains a puzzle and as a result, the ability to treat or reverse the disease is hampered. Sex hormones are known to play a role in the maintenance of the structure and integrity of the human cornea. Hormone levels have been reported to alter corneal thickness, curvature, and sensitivity during different times of menstrual cycle. Surprisingly, the role of sex hormones in corneal diseases and KC has been largely neglected. Prolactin-induced protein, known to be regulated by sex hormones, is a new KC biomarker that has been recently proposed. Studies herein discuss the role of sex hormones as a control mechanism for KC onset and progression and evidence supporting the view that prolactin-induced protein is an important hormonally regulated biomarker in KC is discussed.

Comparison of the efficiency of femtoLASIK and ReLEx SMILE in terms of dioptric error reduction

BACKGROUND AND AIMS

Refractive eye surgery is a rapidly expanding field of ophthalmology and corneal surgery is undergoing constant development leading to less invasive technologies. The goal of this study was to compare the most common femtoLASIK surgery with the newer ReLEx SMILE surgery which is gentler to the cornea. The comparison was made in terms of dioptric error reduction.

METHODS

The studied cohort of patients consisted of two major groups: 30 patients who underwent femtoLASIK surgery and 30 who underwent ReLEx SMILE surgery. -30 patients, 60 eyes. All patients were aged 18-45 years with moderate myopia or astigmatism ranging from -3.25 to -6.0 spherical diopters and from 0 to -1.0 cylindrical diopters. In all, the best corrected visual acuity measured prior to surgery was 1.0. Pachymetry was not comparable because each surgical method was performed at a different time point and the introduction of an innovative method into practice led to a change in selection criteria.

RESULTS

During postsurgical check-ups, the ReLEx SMILE method (0.74) led to lower values of non-corrected visual acuity compared to the femtoLASIK method (0.88), (P<0.001). However, the results changed at the one-year post-surgery check-up, when ReLEX SMILE patients achieved non-corrected visual acuity of 0.97 compared to femtoLASIK patients, who scored 0.83, (P=0.007). Based on data analysis from the automatic refractometer, the average spherical diopters of the femtoLASIK (-0.32 D) were higher than those of the ReLEx SMILE (-0.07 D), (P<0.001). The results for the cylindrical diopters were also significant, (P=0.021). When we compared the spherical equivalent one year after surgery, the difference between methods was significant. The FemtoLASIK method resulted in an average SE -0.55 D compared to -0.09 D for the ReLEx SMILE method, (P<0.001).

CONCLUSION

This study showed that there was a significant difference in results between the two surgical methods of treatment of moderate myopia and astigmatism, in terms of regression of dioptric error, as well as in achievement and maintenance of visual acuity during the observed period. The ReLEx SMILE had better results.

Comparative analysis of choroidal thickness in third trimester pregnant women

Background

The impact of pregnancy on the choroid is still under investigation. The aim of this study is to compare choroidal thickness measurements of healthy pregnant women in the third trimester and healthy non-pregnant women using spectral-domain optical coherence tomography (OCT).

Methods

This cross-sectional study included 122 eyes of 61 women, divided into two groups: 27 healthy pregnant women in the third trimester and 34 age-matched healthy non-pregnant women. Choroidal thickness was measured using Enhanced Depth Imaging OCT at ten different locations: at the fovea and every 500 µm from the fovea up to 2500 µm temporally and up to 2000 µm nasally.

Results

There were no significant differences in the ten measurements of choroidal thickness comparing both groups. Mean subfoveal choroidal thickness was 304.1 + 9.6 µm in the control group and 318.1 + 15.6 µm in the pregnant women group (p = 0.446). There was also no statistically significant association between gestational age and choroidal thickness measurements in the healthy pregnant women group.

Conclusions

Our study showed no statistically difference in choroidal thickness between healthy non-pregnant women and healthy pregnant women in the third trimester.

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.

Corneal clarity measurements in healthy volunteers across different age groups: Observational study

The aim of this study was to standardize and investigate the changes in corneal clarity with age. Densitometry software for the Oculus Pentacam was used to examine corneal clarity at different age groups.A total of 192 eyes from 97 healthy participants were included in this cohort comparative nonrandomized, cross-sectional study. An Oculus Pentcam was used to image the cornea of healthy participants grouped by age (between 10 and 70 years old). Data from the densitometry output have been used to determine clarity in concentric zones and different depths of the cornea.Corneal densitometry (CD) across all ages showed significant differences between groups when divided into the following layers: anterior, central, and posterior or divided into 0 to 2, 2 to 6, and 6 to 10 mm concentric zones (P < .05). The most striking decrease in clarity occurred with age in all 3 layers of the periphery (6-10 mm) (P < .05). In addition, we showed that the 10 to 19-year age group had lower clarity than the 20 to 30-age group (P < .05), and after 30 years, the cornea shows a steady progression of increased or decreased clarity.The values for CD, as well as for separate subdivisions based on layer and surface area, might provide a standard for use in further studies and clinical practice. This study established that relation between CD and age is differed when the cornea is divided into layers and zones. This study suggests that there are other factors that may play an essential role in corneal clarity as well as age.

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.

Diabetes and pachymetry changes in pregnancy

BACKGROUND

Purpose of this study is to evaluate changes in the central corneal thickness (CCT) in patients during the third trimester and postpartum phases of normal pregnancy, pregestational diabetes mellitus (DM), and gestational diabetes mellitus (GDM).

METHODS

This was a prospective study. Patients that fulfilled the inclusion criteria were recruited from the obstetric clinic. They were grouped into normal pregnancy, pregestational DM, and GDM. Ophthalmic assessment and haematological investigations were done during the third trimester (after 28 weeks of gestation) and in the postpartum phase (6 weeks postpartum).

RESULTS

A total of 192 pregnant patients were recruited for this study. Out of the 192 patients, only 143 of them came back for their follow-up 6 weeks postpartum. A total of 70 (36.5%) normal pregnancy patients, 51 (26.6%) DM patients, and 71 (36.9%) GDM patients were included in this prospective study. Our study showed that the CCT decreased postpartum in all three groups. Patients in all three groups did not have significantly different CCT during the third trimester of pregnancy and postpartum phase. However, patients who had thicker CCT irrespective of the grouping during the third trimester also had a thicker CCT post-delivery (p value <0.001). However, these changes did not appear to affect refractive error and visual acuity.

CONCLUSIONS

Diabetes mellitus during pregnancy did not appear to influence the CCT.

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.

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.

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.

Using critical flicker frequency in the evaluation of visual impairment in preeclamptic women

OBJECTIVE

To assess critical flicker frequency (CFF) in normal uneventful pregnancy and preeclampsia.

STUDY-DESIGN

Case-control observational study at the University Hospital Jena and Outpatient Institute for Prenatal Diagnosis and Preventive Medicine. 25 non-pregnant women, 75 uncomplicated pregnant women in first, second and third trimester, and 15 women with overt preeclampsia. For comparison with preeclamptic patients we matched 15 normal pregnant women (mNP) for age, parity, body mass index, current smoking and family history of cardiovascular disease (CVD). We measured CFF using the portable HEPAtonorm Analyzer (nevoLAB GmbH, Germany). This device generates a flickering red light, starting with a frequency of 60Hz, giving the subjective an impression of a steady light. The participant signifies once the impression of a flickering light is recognized, and this CFF is recorded. Mean CFF and standard deviation is automatically calculated. Statistical analysis was performed using SPSS Version 22 for Windows. Following assessment of normal distribution with Kolmogorov-Smirnow test, comparisons were made with univariate and multivariate ANOVA and with unpaired and paired t test for continuous data and with χ² test for categorical data.

RESULTS

Critical flicker frequency in healthy pregnant women does not differ from nonpregnant women. No significant differences in CFF measurements exist in first, second, and third trimester. In preeclampsia, CFF is significantly decreased compared to normal pregnant women (PE 38.80±2.16 vs. mNP 46.23±3.37; p=0.000). This alteration persists even some weeks postpartum (PE 41.17±1.13 vs. mNP 46.45±3.44; p=0.003).

CONCLUSION

In preeclamptic women, CFF is decreased indicating an altered endothelial situation. The finding that CFF remains reduced postpartum may be explained by either the effect of preeclampsia on maternal endothelium causing longer lasting damage or indicate a preexisting endothelial disorder. Up to this point, precise responsible mechanisms for altered CFF in preeclampsia are currently unclear and further studies are needed.

Differential Effects of Hormones on Cellular Metabolism in Keratoconus In Vitro

Keratoconus (KC) is a corneal thinning disease with an onset commonly immediately post-puberty and stabilization by 40 to 50 years of age. The role of hormones in regulating corneal tissue structure in homeostatic and pathological conditions is unknown. Our group recently linked altered hormone levels to KC. Our current study sought to investigate and delineate the effects of exogenous hormones, such as androgen, luteotropin, and estrogen, on corneal stroma bioenergetics. We utilized our established 3D in vitro model to characterize the effects of DHEA, prolactin, 17β-estradiol on insulin-growth factor-1 and -2 (IGF-1, -2) signaling and metabolic function in primary corneal fibroblasts from healthy controls (HCFs) and KC patients (HKCs). Our data showed that exogenous DHEA significantly downregulated IGF-1 and its receptor in both HCFs and HKCs with HKCs showing consistently lower basal pentose phosphate flux. Prolactin caused no significant change in IGF-1 levels and an increase in IGF-2 in HKCs correlating with an increase in ATP and NADH levels. 17β-estradiol led to a significant upregulation in pentose phosphate flux and glycolytic intermediates in HCFs. Our results identified hormone-specific responses regulated in HKCs compared to HCFs revealing a novel role for hormones on bioenergetics in KC.

Evidence-Based Approaches to Glaucoma Management During Pregnancy and Lactation

With increasing maternal age in this decade, there is a parallel rise in the number of pregnant and lactating women affected by glaucoma worldwide. Understanding the diagnosis and management of glaucoma during pregnancy and lactation is essential to preventing blindness from glaucoma in this vulnerable population. This report provides a review of the current literature and offers effective strategies that will overcome the challenges in managing glaucoma during pregnancy and lactation. Practically, glaucoma management during pregnancy and lactation presents a unique challenge for the physician, as the benefit of any treatment must be weighed against the potential risks to the fetus. Prior to initiating or continuing treatment, the physician should be familiar with the various treatment options to manage intraocular pressure during pregnancy and lactation, including the safety of various anti-glaucoma medications as supported by the existing literature and based on the food and drug administration guidelines. A collaborative team effort between the ophthalmologist, obstetrician, and neonatologist in high-risk pregnancies is recommended to optimize care for the mother and fetus.

The effect of assisted reproductive technology on ocular assessments

PURPOSE

The aim was to study the various ocular assessments in women undergoing assisted reproductive techniques (ART).

METHODS

A total of 117 women with infertility were enrolled for study and the ART protocol was followed. The outcome measures were intraocular pressure (IOP), central corneal thickness, corneal endothelial cell counts, Schirmer I test done at baseline (V0), post-oral contraceptive (V1), post-GnRH agonist induction phase (V2), post-conception (V3), third trimester of pregnancy (V4) and three months post-partum (V5). Schirmer I test (without topical anaesthesia) less than 10 mm in at least one eye was considered a criterion for dry eye.

RESULTS

Out of 117 women enrolled for in vitro fertilisation (IVF), only 48 patients conceived. Sixteen women had abortions and remaining 32 women, who had childbirth were followed until three months post-partum. Baseline mean IOP showed a slight decrement and corneal pachymetry and corneal endothelial cell counts showed slight increment from phases V1 to V4 of ART but statistically they were not significant (p > 0.05). At three months post-partum (V5) mean IOP, corneal pachymetry, corneal endothelial cell counts become closer to baseline in both eyes. The number of patients with at least one eye with dryness (Schirmer I less than 10 mm) significantly increased at the third trimester (p = 0.02) and three months post-partum (p = 0.035), whereas in the rest of the phases, it was comparable to baseline (p > 0.05).

CONCLUSION

The ocular physiological changes (IOP, corneal pachymetry and corneal endothelial cell counts) seen in various phases of ART were non-specific. The ART appears to reduce tear secretions as measured by Schirmer I; however, further research would be required to determine the impact of ART on the tear film and whether ART is associated with symptoms and signs of dry eye.

Choroidal thickness in pregnant women: a cross-sectional study

AIM

To investigate choroidal thickness in pregnant women and compare the measurements with those of normal nonpregnant women.

METHODS

Using enhanced depth imaging optical coherence tomography (EDI-OCT), choroidal thickness was measured at the fovea and at 1 mm and 3 mm superior, inferior, temporal, and nasal to the fovea in both healthy pregnant women and nonpregnant women. Pearson correlation analysis was performed to evaluate the relationships between subfoveal choroidal thickness (SFCT) and the demographic and ocular parameters. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using fixed-effects model when Meta-analyses were conducted.

RESULTS

Comparison of choroidal thickness between the groups showed that it was significantly greater in healthy pregnant women's eyes than in normal nonpregnant women's eyes at all locations except at 3 mm superior and 3 mm temporal from the fovea (P<0.05). The mean SFCT was 344.13±50.94 µm in healthy pregnant women's eyes and 315.03±60.57 µm in normal nonpregnant women's eyes, with a statistically significant difference (P=0.008). Pearson correlation analysis showed that age and axial length were significantly related to SFCT in healthy pregnant women, normal nonpregnant women, and all subjects. The results of our cross-sectional study were consistent with the results of the further Meta-analysis, with a pooled weighted mean difference (WMD) of 33.66 µm (95% CI: 26.16 to 41.15) for SFCT.

CONCLUSION

Our results, along with the comprehensive Meta-analysis, suggest that choroidal thickness in healthy pregnant women is greater than that in normal nonpregnant women.

Age-related differences in corneal epithelial thickness measurements with anterior segment optical coherence tomography

PURPOSE

To measure corneal epithelial thickness (CET) in healthy adults and to investigate its variation with age by use of anterior segment optical coherence tomography (OCT).

METHODS

A total of 210 healthy individuals were enrolled and divided into four, almost equally sized groups on the basis of age: 18-29 years (group 1), 30-44 years (group 2), 45-59 years (group 3), and 60-80 years (group 4). The CET and total corneal thickness in the central area (diameter 6.0 mm) of each patient were obtained by Fourier-domain OCT, and the regional thickness and topographic variability were compared among the age groups. In addition, the correlations between the CET and age, gender, and refractive status were analyzed using partial correlation tests and multiple regression analysis.

RESULTS

The CET of the central segment (diameter 2 mm) in groups 1, 2, 3, and 4 were 53.74 ± 3.82, 54.48 ± 3.33, 53.89 ± 3.73, and 53.30 ± 3.36 µm, respectively, demonstrating no significant change with age (P = 0.416). In most of the paracentral and all of the midperipheral zones (annuli 2-5 and 5-6 mm from the center, respectively), the CET differed significantly among the four groups. Correlation analysis suggested that the CET is greater in men than in women and that the CET of both the paracentral and the midperipheral zones is inversely correlated with age. Topographic variability was also inversely correlated with age.

CONCLUSIONS

The CET became thinner with age in the paracentral and midperipheral zones, while the central CET seems to remain constant. Gender differences should be considered in the assessment of CET.

Effects of Hormone Therapy on Intraocular Pressure: The Women's Health Initiative-Sight Exam Study

PURPOSE

Previous studies suggest that hormone therapy favorably affects intraocular pressure (IOP). Here, we examined the association between hormone therapy use and IOP in the context of a large randomized trial.

DESIGN

Secondary data analysis from a randomized controlled trial.

METHODS

We used data from the Women's Health Initiative-Sight Exam (WHISE). Women with prior hysterectomy received oral conjugated equine estrogen (0.625 mg/day) or placebo. Women with a uterus received estrogen plus progestin (medroxyprogesterone acetate 2.5 mg/day) or placebo. IOP was measured 5 years after randomization. Adjusted linear regression models were used to assess the association between hormone therapy and IOP.

RESULTS

The WHISE included 1668 women in the estrogen-alone trial (aged 63-86, mean 72 years) and 2679 women in the estrogen-plus-progestin trial (aged 63-87, mean 72 years). In multivariate analyses, compared to placebo treatment, treatment with estrogen alone was associated with a 0.5 mm Hg reduction of the IOP in the right eye (95% CI: -0.8, -0.1, P = .005) and a 0.6 mm Hg (95% CI: -0.9, -0.3, P < .001) reduction of the IOP in the left eye. In the estrogen-plus-progestin trial, there was no significant difference in IOP between the treatment and placebo groups (P = .30 right eye and P = .43 left eye).

CONCLUSIONS

This study represents an IOP analysis in the largest hormone trial available. Estrogen-alone therapy in postmenopausal women is associated with a small but significant IOP reduction of 0.5 mm Hg. The clinical significance of this small decrease remains to be determined.

Is Estrogen a Therapeutic Target for Glaucoma?

This article's objective is to provide an overview of the association between estrogen and glaucoma. A literature synthesis was conducted of articles published in peer-reviewed journals screened through May 5, 2015, using the PubMed database. Keywords used were "estrogen and glaucoma," "reproductive factors and glaucoma," and "estrogen, nitric oxide and eye." Forty-three journal articles were included. Results indicated that markers for lifetime estrogen exposure have been measured by several studies and show that the age of menarche onset, oral contraceptive (OC) use, bilateral oophorectomy, age of menopause onset and duration between menarche to menopause are associated with primary open-angle glaucoma (POAG) risk. The Blue Mountain Eye Study found a significantly increased POAG risk with later (>13 years) compared with earlier (≤12 years) age of menarche. Nurses' Health Study (NHS) investigators found that OC use of greater than 5 years was associated with a 25% increased risk of POAG. The Mayo Clinic Cohort Study of Oophorectomy and Aging found that women who underwent bilateral oophorectomy before age 43 years had an increased risk of glaucoma. The Rotterdam Study found that women who went through menopause before reaching the age of 45 years had a higher risk of open-angle glaucoma (2.6-fold increased risk), while the NHS showed a reduced risk of POAG among women older than 65 who entered menopause after age ≥ 54 years. Increased estrogen states may confer a reduced risk of glaucoma or glaucoma-related traits such as reduced intraocular pressure (IOP). Pregnancy, a hyperestrogenemic state, is associated with decreased IOP during the third trimester. Though the role of postmenopausal hormone (PMH) use in the reduction of IOP is not fully conclusive, PMH use may reduce the risk of POAG. From a genetic epidemiologic perspective, estrogen metabolic pathway single nucleotide polymorphisms (SNPs) were associated with POAG in women and polymorphisms in endothelial nitric oxide synthase, a gene receptive to estrogen regulation, are associated with glaucoma. The study concluded that increasing evidence suggests that lifetime exposure to estrogen may alter the pathogenesis of glaucoma. Estrogen exposure may have a neuroprotective effect on the progression of POAG but further studies need to confirm this finding. The role of sex-specific preventive and therapeutic treatment may be on the horizon.

Pregnancy and the Eye

Pregnancy causes significant changes in all systems of the body. Although most of them are physiological, they may also lead to pathological consequences. The resulting pathological changes may occur for the first time or existing diseases affected by pregnancy can become more serious or change course. Diseases specific only to pregnancy may arise. Like all systems of the body, the visual system is also affected by pregnancy, developing a wide range of physiological and pathological changes. Knowing the ocular physiological changes and diagnosing eye diseases that may develop during pregnancy, and preventing and treating these diseases is crucial to ensure the baby's healthy development. Therefore, we have reviewed the conditions that an ophthalmologist should recognize, follow-up, and pay attention to during treatment and summarized them under the topic "pregnancy and the eye".

Evaluation of Sex Differences in Corneal Hysteresis

Purpose

To study sex differences in corneal biomechanical parameters in Egypt as regards to corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc).

Methods

This is a cross-sectional observational study that includes 350 eyes of 350 normal subjects (175 men and 175 women) who were evaluated using the Reichert ocular response analyzer (ORA) to measure CH, CRF, IOPg, and IOPcc.

Results

The mean CH in men was 9.69 ± 2.05 mm Hg (range 5.7–14.6 mm Hg) and in women 10.41 ± 1.65 mm Hg (range 7–14.4 mm Hg) with a p value of 0.00038. The mean CRF in men was 9.54 ± 2.16 mm Hg (range 4.9–14.4 mm Hg) and in women was 10.37 ± 1.71 mm Hg (range 7.3–15.5 mm Hg) with a p value of 0.00008. The mean IOPg in men was 14.78 ± 4.15 mm Hg (range 7.2–26.5 mm Hg) and in women was 15.44 ± 3.3 mm Hg (range 8.6–23.7 mm Hg) with a p value of 0.09. The mean IOPcc in men was 16.2 ± 4.08 mm Hg (range 10.9–28.9 mm Hg) and in women was 15.86 ± 3.41 (range 9.7–24.2 mm Hg) with a p value of 0.4. There was a statistically significant difference between men and women in CH and CRF while IOPg and IOPcc showed no statistically significant difference (p>0.05).

Conclusions

There is a statistically significant difference between men and women in CH and CRF, where women show higher values, while no statistically significant difference exists between the groups in IOPg or IOPcc.

Measurement of choroidal thickness and macular thickness during and after pregnancy

AIM

To investigate the effect of pregnancy on subfoveal choroidal thickness (SFCT) and macular thickness in both pregnant and not pregnant healthy women.

METHODS

Twenty-nine healthy pregnant women in their third trimester and 36 age-matched healthy women were enrolled in a prospective, cross-sectional study. Foveal and parafoveal thickness in the four quadrants and SFCT were measured by optical coherence tomography (OCT) in the healthy pregnant women (i.e. study group) and healthy women (i.e. control group). OCT measurements were again measured 3mo after delivery in the study group.

RESULTS

Mean SFCT measurements in the control group, pregnant women of the study group, and after delivery of the study group were 320.86±59.18 µm, 387.97±59.91 µm, and 332.40±26.03 µm, respectively. There was a statistically significant difference in the mean SFCT values between pregnant women of the study group and the control group (P=0.000). Foveal and parafoveal thickness values were not statistically significant in either the study or control group.

CONCLUSION

SFCT increases during pregnancy and returns to normal range in the three months after delivery. Macular thickness does not show any change during pregnancy.

Corneal thickness differences between sexes after oxybuprocaine eye drops

PURPOSE

We aimed to analyze the corneal thickness (CT) values of female and male subjects before and after instillation of oxybuprocaine 0.4% anesthetic eye drops.

METHODS

The CT of 30 female subjects and 28 male subjects was measured using scanning-slit corneal topography (Orbscan Topography System II, Orbscan, Inc, Salt Lake City, UT). Measurements were carried out before and 3 minutes after the instillation of oxybuprocaine 0.4% eye drops.

RESULTS

The difference between the baseline values and those obtained after anesthesia ranged as follows: male subjects: central, -26 to +24 μm; superior, -24 to +23 μm; inferior, -19 to +20 μm; nasal, -25 to +30 μm; and temporal, -21 to +20 μm; female subjects: central, -16 to +24 μm; superior, -19 to +32 μm; inferior, -14 to +34 μm; nasal, -19 to +33 μm; and temporal, -36 to +16 μm. No significant differences were found in any corneal location in male subjects. The differences were significant at inferior (p = 0.001) and nasal (p = 0.011) corneal sites in female subjects.

CONCLUSIONS

Oxybuprocaine anesthetic eye drops induce significant CT increases in female subjects but not in male subjects.