review pp. 196-199 (2013)

Particularities of in pregnancy

1 George Iancu , Abstract Valeria Coviltir2, Raluca Iancu3, Although ocular conditions are commonly encountered in pregnancy, their management in pregnancy and during Catalina Corbu4 labor is still debate. Our review synthesizes the existing evidence on pregnancy and labor impact on visual outcome in myopic patients. We aimed to evaluate the changes in ocular physiology during pregnancy, the characteristics 1. Department of Obstetrics and Gynecology, of myopia in pregnant population, the impact of epidural anesthesia and mode of delivery on myopia progression. University of Medicine High hormonal levels of pregnancy change corneal thickness and curvature, decrease sensitivity and and Pharmacy “Carol Davila” reduce intraocular pressure. The existing evidence for ocular changes with pregnancy and expulsive and Filantropia Clinical Hospital effort in labor is rather poor. Myopic patients did not develop worsening of visual function after Bucharest (Romania) spontaneous vaginal delivery in any of the existing studies. Epidural anesthesia should be offered 2. Department of , unrelated to ocular condition. Until further evidence will become available, vaginal delivery should be University of Medicine and Pharmacy the standard for patients with ocular conditions in the absence of obstetrical contraindications. “Carol Davila” Keywords: myopia, labor, hormonal level, vaginal delivery Bucharest (Romania) 3. Department of Ophthalmology, University of Medicine and Pharmacy “Carol Davila” and Emergency Introduction commonly related to connective tissue and retinal University Hospital Bucharest (Romania) Major changes take place in the maternal body du- abnormalities. This type of myopia accounts only of 4. Department of Ophthalmology, ring pregnancy and delivery. Some of these changes a small proportion of the overall myopic population University of Medicine are physiological, well tolerated and totally reversible and, to date, there is no known isolated gene asso- and Pharmacy “Carol Davila” a few months postpartum, while others can have a ciated with physiologic myopia(2). Bucharest (Romania) major impact on maternal body. Systemic changes There is also a high incidence of complications Correspondence: Dr. Valeria Coviltir, that occur in pregnancy can influence the visual associated with pathological myopia which were e-mail: valeriacoviltir@ yahoo.com function. Some changes are reversible while others presumed to increase further more during pregnancy can cause permanent vision loss. One of the pre- and labor. The retinal complications of high myopia All authors contributed equally to conceiving existing ocular disorders altered by the pregnancy, leading to blindness are: , degene- the review, data collection, manuscript writing under debate for a long time, is myopia, a common ration of the at the macula, behind the and editing and approval of the final version. pathology in pregnancy. Myopia is a well known retina, due to formation of a choroidal neovascular problem worldwide, with large global variation in membrane, formation of a macula hole. Patients prevalence and increasing frequency and severity with high myopia (spherical equivalent at least -6.0 throughout the world. Its magnitude is still not D) are more susceptible to ocular abnormalities. The completely known(1). prevalence of was higher in myopic adults, Non-pathological myopia is commonly referred to and the risks of chorioretinal abnormalities such as physiological, simple or school myopia. In non- as retinal detachment, chorioretinal atrophy and pathologic myopia, the refractive structures of the lacquer cracks increased with the severity of myopia eye develop within normal limits; however, the re- and greater axial length. Myopic adults were more fractive power of the eye does not correlate with the likely to have tilted, rotated, and larger discs as well axial length. The degree of non-pathologic myopia as other abnormalities(3). is usually minimal to moderate (< 6.00 diopters) During the pregnancy, hormone secretion repre- with onset usually during childhood or adolescence. sents the main cause that will occur and will reach Pathologic myopia is generally classified as high the peak during labor and delivery. The estrogen, myopic that is progressive and ge- progesterone, somatostatine, deoxycorticosterone, nerally presents very early in childhood. Pathologic corticosteroid-binding globulin (CBG), cortisol, free myopia is usually defined as spherical equivalent > cortisole, thyroxine, triiodothyronine and aldost- 6.00 diopters or axial length > 26.5 mm. Patients erone levels are higher than in non-pregnant wo- with high axial myopia are at greater risk of develo- men. Hormones level will reach their pre-pregnancy ping progressive retinal degeneration or other vision values a few months after breastfeeding has been threatening pathology(2). stopped(4). It is well documented that pathological high myopia The aim of the present review is to evaluate the Received: May 17, 2013 shows evidence of familial inheritance. High myopia changes in ocular physiology during pregnancy, the Revised: is also a symptom of several multi-system diseases. characteristics of myopia in pregnant women and the July 24, 2013 Accepted: The genetic mutations have been identified and the impact of epidural anesthesia and mode of delivery August 04, 2013 subsequent structural defects of the eye are most on myopia progression. 196 +(ċƫĊƫđƫ+ċƫăąƫĨąĥĂĀāăĩ Iancu et al. Particularities of myopia in pregnancy gineco eu

Impact of pregnancy on ocular physiology months after delivery(8). The general consensus is that The effect of pregnancy on eye function has been myopic shift is caused by the increased curvature of extensively studied. Corneal changes are most likely the , while the refractive changes develop due due to water retention and include a decrease in to changes in corneal curvature or thickness and/or corneal sensitivity and an increase in both corneal tear film(4). thickness and curvature. Therefore, despite previo- Several studies prove that refraction disorders usly effective use of contact lenses, many patients triggered by pregnancy are marked by myopization, find difficult to manage them during pregnancy. usually not very significant and always regressive It is best to delay fitting new contact lenses until within six weeks after childbirth(9). According to those several weeks postpartum. Corneal changes occur studies, there is a tendency towards worsening of the usually late in pregnancy and may produce tempo- refractive function in the first half of pregnancy in rary alterations in refraction, making pregnancy a women with refractive disorder history(7). contraindication for refractive eye surgery. This is Refractive surgery during pregnancy is questio- mostly due to the fact that results of refractive eye nable due to temporary changes in ocular anatomy. surgery shortly before, during or after pregnancy A study on refractive changes after photorefractive cannot be predicted adequately. It is recommended keratectomy in pregnant patients revealed the im- to delay surgery and wait until refraction is stable in pact of pregnancy on corneal wound healing after the postpartum period. Pregnancy may also induce photorefractive keratectomy. 18 eyes were analyzed dry-eye syndrome due to disruption of lachrymal in women that became pregnant during follow-up acinary cells(5). period after keratectomy. During the postpartum The second half of the pregnancy is associated period, there was an improvement in 50% of the eyes, with moderate decrease of intraocular pressure in with reduction of the corneal haze and associated normal eyes, which may be even greater in patients myopic regression(10). with preexisting ocular . This occurs due to increased aqueous outflow, decreased epis- Natural vaginal delivery or cesarean section cleral venous pressure, decreased scleral rigidity and for myopic women? generalized acidosis during pregnancy. Intraocular Ocular pathology has been considered for a long pressure typically returns to pre-pregnancy levels time important for the decision regarding the mode by two months postpartum(6). of delivery. Myopia and other risk factors for retinal A hormonally mediated increase in pigmentation detachment were frequently used as indication for around the eyes and cheeks is common and is called cesarean section in the past; it was thought that in- chloasma or ‘mask of pregnancy’. Benign spider angi- creased effort, mainly in the second stage of labor, omas commonly develop on the face and upper body. would augment the risks of retinal detachment. These changes usually resolve postpartum. , The indication for cesarean delivery was usually the often unilateral, occurs during or after pregnancy attribute of the ophthalmologist. probably as a result of defects in the levator apone- Most of the studies arise from Eastern Europe, urosis caused by fluid, hormonal, and stress-related where the large amount of cesarean sections for changes of labor and delivery(7). ophthalmic pathology has been considered a public health problem. One study from Poland retrospecti- Particularities of myopia in pregnant women vely analyzed the prevalence of cesarean section for During pregnancy a shift towards myopia or an in- ophthalmic conditions between 2000 and 2008. The crease of myopia usually develops. This shift, however, prevalence was 2.04%, the indication being usual- is generally reversed after delivery or breast-feeding(2). ly written by the ophthalmologist. Myopia was an The presence of estrogen receptors has been proposed indication for 57% of the cases; other pathologies as cause of the physiological modifications in the cor- considered a contraindication for spontaneous de- nea and lens during pregnancy, often leading to some livery were , past or imminent retinal degree of myopization and deficit. detachment or glaucoma(11). Ophthalmic pathology The increases its central thickness between 1 was the indication for cesarean section in over 20% and 16 μm due to edematous changes secondary to of the non-obstetrical indications in another Polish fluid retention in pregnancy. There is evidence that retrospective analysis, exceeded only by hypertensive during pregnancy the cornea thickens secondary to pathology(12). excessive hydration of the stroma due to the activation There are a few studies with a small number of pati- of estrogen receptors and because of the influence of ents that assessed the changes in ocular morphology these hormones on the elasticity and biomechanics and physiology after vaginal delivery. In 1996, Prost of corneal tissue. Some authors studied the refractive and contributors studied 46 patients with high myo- changes during pregnancy and found that about 14% pia and/or retinal detachment history; there was no of pregnant women had some changes in their visual progression of the changes after spontaneous vagi- acuity, refractive errors and myopic shift, changes nal delivery. Therefore, the authors pleaded for the that will return to pre-pregnancy levels within a few safety of vaginal delivery in myopic patients(13). Neri 197 +(ċƫĊƫđƫ.ċƫăąƫĨąĥĂĀāăĩ review

and colleagues conducted a prospective trial in 1985 and cerebral circulation were examined in a study on 50 pregnant patients with high myopia; fundus performed on 290 patients with moderate or severe examination was performed in all patients before and myopia and in 25 healthy women during pregnan- after spontaneous vaginal delivery. There were no cy, delivery and postpartum. About 255 patients significant changes observed; the authors concluded delivered spontaneously vaginally with prolonged that spontaneous vaginal delivery is safe for the high epidural anesthesia during first and second stages myopic patient(14). Another study assessed the impact of labor. Epidural anesthesia was accompanied by of spontaneous vaginal delivery on high-risk retinal pa- decreasing vasoconstriction and both cerebral and thology; there was no worsening of retinal status after ocular circulation improvement; there was no pro- delivery, pointing as well towards spontaneous vaginal gression of myopic changes after delivery at one delivery for this category of population(15). Other small year follow-up(23). studies provided the same conclusion(16,17). Another study was performed on a total of 315 Data on pregnancy and delivery impact on ocular pregnant women from which 290 (92.1%) had myo- pathology is somehow confusing. A Russian study on pia and 25 healthy patients (7.9%). An algorithm over 300 pregnancies with average and high myopia of pregnancy and delivery monitoring for myopic used, apart from conventional ophthalmology exam, patients was developed comprising of ophthalmo- rheoophthalmography to analyze intraocular pressure logic examinations and rheoophthalmography per- changes and ocular hemodynamics during pregnancy formed during delivery. Ocular hemodynamics and and delivery; the authors advocated that the moni- intraocular pressure and their dependence on the toring algorithm they used, together with prolonged parameters of central hemodynamics and volumetric epidural analgesia in labor, managed to reduce the cerebral blood velocity were analyzed during different rate of operative delivery from over 20% to 1.3%(18). stages of spontaneous delivery. Prolonged epidural However, there is no evidence in the literature that anesthesia normalized the hemodynamics of the operative delivery decreases the risk of retinal deta- ciliary tract and optimized the delivery in women chment, while there is solid evidence that epidural with average and high myopia(18). analgesia slows the progress of labor and increases Travkin and contributors used of vasodilators and the rate of instrumental deliveries(19). prolonged epidural anesthesia in pregnancy, ana- A retrospective study conducted in Croatia analysed lysing the impact on retinal blood flow; they used the change in habits concerning the management of the rheographic quotient as a measure of uveal tract pregnancy in myopic patients between 2003 and 2009. blood flow. The study promoted the prevention and Three groups were analysed depending on the severity treatment of retinal degeneration in myopic pregnant of myopia, The prevalence of cesarean sections and patients, using prolonged epidural anesthesia and the impact on visual function was compared between vasodilators(24). myopic patients and the existing data for emmetropic patients. There were no significant differences found Ophtalmic pathology in the rate of cesarean section; the visual function was Ophthalmic pathology has confused obstetricians similar postpartum when compared with antepartum and ophthalmologists for a long time regarding the values independent of the mode of delivery(20). impact of pregnancy and delivery on refractive changes There are many practitioners who recommend either in myopic eye. It was believed that the highest risk an assisted vaginal delivery with forceps or vacuum of worsening of refractive ocular pathology occurred extraction or a caesarean section not only for high during labor when the physical strain is at paroxysm. myopia, but also in cases of other pre-existing eye A study on over 350 patients found an incidence of diseases such as retinal detachment, diabetic reti- of 10.5%; there was no intra- nopathy, or glaucoma. This is mainly based on the ocular or retrobulbar bleeding associated(25). Increase increase of intraocular pressure during the second in intraocular pressure in second stage of labor was stage of labor. These recommendations, however, considered a risk factor for retinal detachment and are not evidence-based(21). As far as we know, there worsening of visual function. However, the studies on are not so many published trials that have reported eye changes in postpartum patients after spontaneo- any significant adverse retinal changes after vaginal us delivery contradicted what was thought to belong delivery, therefore preexisting is not an to common sense. There was no significant adverse indication for instrumental or operative delivery(22). change in myopic eyes in any of the studies. The lack of adverse effects of increased pressure during labor Epidural anesthesia was attributed to an equal distribution of intraocular in myopic pregnant patients pressure on all directions. Gradually, with accumula- Another concerning issue for both obstetricians tion of evidence, ocular conditions including myopia and ophthalmologists is the impact of epidural an- were not considered an indication for cesarean section esthesia, commonly used in current practice, for anymore. Instrumental delivery was also advocated patients with myopia. Eye fundus, functional state of to decrease the risks of retinal detachment in myopic retina, intraocular pressure, central hemodynamics patients. However, there is no evidence to support that 198 +(ċƫĊƫđƫ+ċƫăąƫĨąĥĂĀāăĩ Iancu et al. Particularities of myopia in pregnancy gineco eu decreasing the maternal expulsive effort and reducing exertion on myopia, which was not confirmed in any the duration of second stage of labor would make any study on pregnant patients. difference concerning maternal visual outcome. The reduced number of studies on pregnancy and Persisting resistance to the scientific evidence was labor impact on ocular physiology and refractive patho- encountered in East European countries that conti- logy is one of the main limitations of our review; also, nued to have a high incidence of cesarean section in most of the existing studies on pregnancy and labor population with ocular pathology. Most of the recent effects on myopia have a small number of patients, studies on myopia in pregnancy were conducted in limiting the statistical strength. There are no rando- Poland, Bulgaria or Russia, in an attempt to decrease mized trials to date to assess the potential effects of the incidence of cesarean section for non-obstetric pregnancy and labor on visual function and to provide causes. The indication for cesarean section was usu- firm conclusions. Apart from the small sample size and ally given by the ophthalmologist rather than the the non-randomized design, another major drawback of obstetrician. A decrease in the number of cesarean the studies is the limited accessibility due to language sections in patients with ophthalmic pathology in utilized. Moreover, most of the reviewed studies were Eastern Europe was observed at present(8,11). published in Polish, Russian or Bulgarian, limiting the There are some studies that support the negative understanding and a full insight into the results because impact of physical strain on myopia progression(26,27). of the language barriers(11,13,17,18,24). However, the physical effort considered is occupatio- nal, involving repeated Valsalva maneuver performed Conclusions over the years, on a long-term basis; on the contrary, There is no evidence that myopic changes worsen Valsalva maneuver in labor is short acting, lasting after vaginal delivery. All the existing studies failed only for a few hours maximum. Also, the average age to identify any adverse changes after spontaneous of the population studied was significantly higher vaginal delivery in patients with refractive pathology (over 50 years old) compared to the average age of or history of retinal surgery. Epidural anesthesia the pregnant patients. It is well known that the risk should be offered in pregnancy related to obstetrical for retinal detachment in myopia increases with indication. Until further well-conducted studies will the age, because of multiple factors, including vari- become available, spontaneous vaginal delivery sho- ous degenerations, vitreal liquefaction and retinal uld be the preferred mode of delivery in the absence breaks(28,29). All these confounders should be exclu- of any obstetrical indications, for myopic patients ded to accurately analyze the impact of the physical and/or history of retinal pathology. „

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