emedicine spesial consideration in pregnancy eye

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pregnancy and eye disease dklalakenkfjeifjja kujiroe kdhajsd referat mata tugas dr JFT

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verviewNumerous physiologic effects occur within the body during pregnancy, and the eye is no exception. This article outlines both normal physiologic changes and pathological changes in the eye that can occur from pregnancy.[1, 2, 3] Moreover, a brief discussion of ocular medications and their potential effects on the fetus are reviewed.Physiologic Ocular Changes Occurring During PregnancyCorneaCorneal sensitivity has been found to be decreased in most pregnant women, where a majority of changes occur in the third trimester and then reverse in postpartum. One potential mechanism may be related to the slight increase in corneal thickness that may develop from corneal edema.[4] Furthermore, an increase in corneal curvature and steepening may also occur. These changes have been reported to develop even in the postpartum period during breastfeeding. However, corneal curvature is reversible upon cessation of breastfeeding.Contact lens intolerance may occur during pregnancy as a result of a change in corneal curvature, increased corneal thickness/edema, or an altered tear film. In any case, it is recommended that one should wait several weeks postpartum before prescribing to a new refraction. Additionally, decreased or transient loss of accommodation may occur during pregnancy or within the postpartum period.Newly developed Krukenberg spindles have been observed early in pregnancy. The mechanism presumably is related to hormonal changes (eg, low progesterone levels). However, by the third trimester, an increase in progesterone and aqueous outflow often result in decreased or absence of Krukenberg spindles.Intraocular pressureA decrease in intraocular pressure has been shown to occur during pregnancy and often persists for several months postpartum. Various mechanisms have been described for this observation: an increase in aqueous outflow; a decrease in systemic vascular resistance, leading to decreased episcleral venous pressure; generalized increased tissue elasticity, leading to decreased scleral rigidity; and generalized acidemia during pregnancy.This decrease in intraocular pressure may have implications for pregnant women with preexisting glaucoma, since improvement of the disease during pregnancy has been reported in a few cases.[5] Visual field changesWide speculation exists about the degree and mechanism of visual field changes that may occur in pregnant women. Types of field loss may include bitemporal loss, concentric constriction, and enlarged blind spots. Proposed mechanisms are equally diverse and include changes to the pituitary gland that may affect the optic chiasm. These asymptomatic visual field changes were shown to be completely reversible postpartum. However, pregnant women with symptomatic visual field loss warrant further investigations.External changesA decrease in conjunctival capillaries and an increase in the granularity of conjunctival venules have been reported to occur; each being reversible during the postpartum period.Another common external result of pregnancy is changes to the skin called chloasma. Due to increased hormone levels (ie, progesterone), some pregnant women experience increased pigmentation around the eyes and cheeks. The pigmentation changes tend to fade slowly postpartum. Pathologic Ocular Changes During PregnancyPregnancy-induced hypertension (preeclampsia)The onset of hypertension (>140/90 after 20 wk) in an otherwise normotensive pregnant woman with proteinemia (>300 mg/24 h) is the minimal criteria needed to diagnose a patient with preeclampsia. Furthermore, if these changes are associated with seizures, which are not attributed to any other cause, then the disorder is classified as eclampsia. The incidence of preeclampsia is approximately 5%, and it is more common in primigravids, in younger and older women, and in those patients with maternal systemic diseases. The onset of this disorder is usually after the 20th week of gestation.Preeclampsia has various maternal and fetal consequences. In up to one third of cases, ocular sequelae have been reported. The most common ocular complaint is visual blurriness; however, other symptoms have also been noted, including photopsias, scotomas, and diplopia. The protean ocular manifestations include retinopathy, optic neuropathy, serous detachments, and occipital cortical changes.The changes that occur in retinopathy due to preeclampsia are similar to changes from hypertensive retinopathy. The most common finding is focal retinal arteriole narrowing, which also may be diffuse. Other changes may include retinal hemorrhages, edema, exudates, nerve fiber layer infarcts, and vitreous hemorrhage secondary to neovascularization. A positive correlation exists between the severity of preeclampsia and the degree of retinopathy; however, most changes are reversible once preeclampsia resolves. Preeclampsia retinopathy may be more severe with underlying diabetes, chronic hypertension, and renal disease.Optic nerve changes that have been reported include papilledema, acute ischemic optic neuropathy, and optic atrophy.Serous exudative retinal detachments may occur in severe preeclampsia or eclampsia. They tend to be bilateral, bullous, and with preeclampsia retinopathy changes. The underlying mechanism is thought to be related to choroidal nonperfusion and resultant subretinal leakage. Most patients with serous detachments have resolution of symptoms a few weeks within postpartum.Cortical blindness, although a rare complication, has been a reported cause of vision loss in patients with preeclampsia. Cerebral edema is believed to be the mechanism of vision loss. Two proposed theories may account for the cerebral edema. One theory suggests that vasospasm causes transient ischemia and produces cytotoxic edema. The other theory explains that preeclampsia causes increased permeability from circulatory dysregulation, thus providing vasogenic edema. Treatment or resolution of preeclampsia and the resultant cerebral edema usually parallels visual recovery.Preeclampsia may cause certain nonvision-threatening changes in the eye, including conjunctival vascular spasm or tortuosity, papillary mydriasis, ptosis, and nystagmus.Central serous retinopathyAlthough not typical, central serous retinopathy (CSR) has been reported to occur during pregnancy. Although more common in the third trimester, it may also occur during the first or second trimesters. The condition resolves spontaneously in the first few months postpartum and has been known to recur in future pregnancies, usually in the same eye. The underlying mechanism remains unclear.Benign intracranial hypertensionBenign intracranial hypertension (BIH), also known as pseudotumor cerebri, is defined as increased intracranial hypertension and its possible sequelae, with normal cerebrospinal fluid composition and normal neuro-imaging. It typically occurs in obese females in their third decade of life. Interestingly, pregnancy does not increase the risk of developing BIH. If BIH does occur, it usually presents in the first trimester but may occur later.BIH does not carry any fetal consequences and carries the same visual outcome in nonpregnant patients. Treatment for BIH in pregnancy is similar to that in nonpregnant patients with a few considerations. First, intense weight loss is not recommended because of risk to fetal viability. Second, carbonic anhydrase inhibitors are contraindicated during pregnancy due to the potential fetal teratogenic effects. Thirdly, the use of diuretics poses the risk of electrolyte and placental blood flow changes. Reports exist of spontaneous improvement with no treatment and very close follow-up care of optic nerve function. However, with visual compromise, interventions, such as bed rest, lumbar puncture, optic nerve sheath decompression, and lumboperitoneal shunting, have been reported.Occlusive vascular disordersIt is well appreciated that pregnancy represents a hypercoagulable state, through various changes that occur with platelets, clotting factors, and arteriovenous flow dynamics. Such changes may be related to the development of retinal artery and vein occlusions, disseminated intravascular coagulopathy (DIC), thrombotic thrombocytopenic purpura (TTP), amniotic fluid embolism, and cerebral venous thrombosis.Both branch and central retinal artery occlusions have been reported to occur in pregnancy. Although a hypercoagulable workup may detect an abnormality, routine hematological workup may be unremarkable. A case report exists of bilateral central retinal artery occlusion from amniotic fluid embolism, which in and of itself is a potentially fatal condition. Retinal vein occlusions are less common than arterial occlusions.DIC is characterized by widespread small vessel thrombosis often associated with hemorrhage and tissue necrosis. It may occur with complications in pregnancy, such as abruptio placentae, severe preeclampsia, complicated abortion, and intrauterine death. The choroid is the most common location in the eye for DIC to manifest. Patients often complain of visual loss from choroidal infarction or hemorrhage, retinal pigment epithelial, or serous detachments usually located in the posterior pole. Visual recovery usually occurs once the DIC resolves; however, mild pigmentary changes may persist.TTP is a rare disorder characterized by small vessel thrombosis, thrombocytopenia, microangiopathic hemolytic anemia, neurologic and renal dysfunction, and fever. Visual symptoms may occur due to serous retinal detachment, retinal artery narrowing, retinal hemorrhage, and optic nerve head edema. The central nervous system may be involved, and the most common visual complaint is a homonymous hemianopia.Antiphospholipid antibody syndrome is another condition that warrants consideration. In this syndrome, patients are in a thrombophilic state and are prone to recurrent arterial and/or venous thrombosis. Diagnostic criteria include clinical evidence of recu