PREGNANCY-RELATED RETINAL DISEASE

Pregnancy may affect the specific findings present in otherwise common disorders such as central serous retinopathy or it may alter preexisting problems such as diabetic retinopathy. The treatment of otherwise common problems such as toxoplasmic retinochoroiditis may

be made more problematic because of concern for the fetus. Systemic complications of pregnancy, including preeclampsia, toxemia of pregnancy, and amniotic fluid embolism, may cause chorioretinal disease more specific to pregnancy.

Symptoms

In the pregnant woman, visual symptoms such as blurred vision, photopsias, or visual field defects may be related not only to retinal disease but also to refractive changes, optic nerve disease, or cerebrovascular alterations.

Clinical Findings

Central serous chorioretinopathy (CSC) is characterized by localized serous neurosensory retinal detachments in the macula. It typically develops in the third trimester of pregnancy. The finding of subretinal fibrin is more common in pregnant women than in nonpregnant patients.

Diabetic retinopathy is characterized by nonproliferative changes, including microaneurysms, retinal hemorrhages, cotton wool spots, venous beading, intraretinal lipid, and retinal thickening (edema). Proliferative changes include neovascularization of the optic disc and retina.

Preeclampsia and toxemia produce retinal changes that are, in part, secondary to systemic hypertension that may cause vasospasm of the retinal and choroidal circulations. Hypertension-associated retinal findings in pregnancy range from arteriolar narrowing to central retinal artery occlusion. Choroidal vasospasm or infarction may result in retinal pigment epithelial changes (Elschnig spots) and exudative retinal detachments (which resolve after delivery).

Ancillary Testing

Usually, the ophthalmoscopic examination is sufficient to ascertain the diagnosis of retinal disorders in pregnant patients. Fluorescein angiography may be performed without harm to the mother or fetus but is used sparingly. Fluorescein angiography demonstrates choroidal nonfilling, leakage of dye from the optic disc and deep retinal lesions, and retinal pigment epithelial window defects. Indocyanine green angiographic findings in patients with preeclampsia include nonperfusion in

the early phases of the angiogram and staining of the choroidal vasculature with subretinal leakage in the late phases.

Pathology/Pathogenesis

It is not known whether CSC in pregnancy is coincidental to or secondary to pregnancy. It has been linked to various hypercortisolemic states. Serum cortisol levels increase dramatically throughout pregnancy and peak in the third trimester.

Pregnancy is a risk factor for progression of diabetic retinopathy. Women with longer duration of diabetes, hypertension, or rapid tightening of blood glucose control at the onset of pregnancy are more likely to have progression of retinopathy.

Hypertension, hypercoagulability, and, in patients with toxemia of pregnancy, disseminated intravascular coagulopathy play a role in the formation of exudative retinal detachments and in retinal/choroidal infarction.

Treatment/Prognosis

In those with CSC, the visual prognosis is generally good, with resolution of subretinal fluid and recovery of vision shortly after delivery. Central serous retinopathy may or may not recur in subsequent pregnancies. Pregnant patients with diabetes should have regular dilated funduscopic examinations to screen for diabetic retinopathy. Laser treatment is applied with the same criteria used in nonpregnant patients. The primary treatment for women with preeclampsia/toxemia is delivery and management of hypertension.

Systemic Evaluation

Hypertension is a common association of CSC. Pregnant patients are usually under tight control of their diabetes, but the ophthalmologist should keep the obstetrician informed of the patient’s retinal status. Occasionally, the ophthalmologist may be the first physician contacted by a preeclamptic patient with visual symptoms. The obstetrician should be notified urgently.

Fundus photographs of a 24-year-old woman who developed high-risk proliferative diabetic retinopathy in her first trimester of pregnancy. She had massive optic disc neovascularization despite extensive panretinal photocoagulation and required pars plana vitrectomy.

This 21-year-old woman with preeclampsia/toxemia of pregnancy reported a sudden loss of vision of her right eye. She had a large exudative neurosensory retinal detachment of her right macula.

Central serous chorioretinopathy may develop during pregnancy, usually in the third trimester. The presence of subretinal fibrin suggests very active leakage.

Subretinal fluid and fibrin were found superior to the optic disc in the left eye of the same patient.

Fluorescein angiogram of the same patient reveals intense hyperfluorescence in the right macula.

The left eye had numerous hyperfluorescent spots in the region of the exudative retinal detachment superior to the optic disc. The hyperfluorescence was due to increased choroidal permeability and breakdown of the outer blood-retinal barrier as a result of choroidal vasospasm and ischemia.

RADIATION RETINOPATHY

Ionizing radiation from external beam radiography or local sources (radioactive eyewall plaques) can induce a retinopathy that closely resembles diabetic retinopathy clinically and pathologically. Treatment for intracranial, orbital, nasopharyngeal, and cutaneous tumors may lead to radiation retinopathy. The radiation doses associated with retinopathy range from 11 to 35 Gy. The onset of radiation retinopathy ranges from 1 to 8 years following the exposure to radiation.

Symptoms

Patients may have few symptoms in the early stages of radiation retinopathy. Reduced vision is usually associated with macular hemorrhages, edema, ischemia, or vitreous hemorrhage.

Clinical Features

The earliest clinical signs are those related to capillary occlusion: cotton wool spots, microaneurysms, retinal telangiectasis, lipid exudation, and intraretinal hemorrhages. Neovascularization develops on the disc and/or retinal surface, and may involve the iris if untreated.

Some patients may also have optic disc edema indicative of associated radiation optic neuropathy.

Ancillary Testing

Fluorescein angiography confirms the presence of capillary occlusion and neovascularization. Foveal capillary dropout suggests a poor visual prognosis.

Differential diagnosis includes diabetic retinopathy, leukemia, sickle cell retinopathy, and branch retinal vein occlusion.

Pathology/Pathogenesis

Radiation retinopathy results from damage to the endothelial cells of the retinal blood vessels. As in diabetes, capillary occlusion in the inner retina is the predominant finding. Inner retinal neurons are also lost. Radiation induces DNA damage that leads to progressive retinal cell death.

Treatment/Prognosis

The treatment for radiation retinopathy is virtually the same as for diabetic retinopathy. Laser photocoagulation is applied for macular edema and neovascularization, and vitrectomy is useful for nonclearing vitreous hemorrhage. Two thirds of eyes maintain visual acuity of 20/200 or better. Visual loss is related to macular edema and ischemia, vitreous hemorrhage, and neovascular glaucoma.

Systemic Evaluation

A history of ocular or head and neck radiation is necessary to make the diagnosis of radiation retinopathy. The oncologist should be notified when radiation retinopathy is detected.

Radiation retinopathy demonstrates ischemia-related findings that include optic disc pallor, cotton wool spots, and retinal arteriolar occlusion.

Radiation retinopathy may be more severe in patients with diabetic retinopathy or other retinal vascular disease. This patient had progression of diabetic retinopathy following orbital radiation.

Fluorescein angiography in radiation retinopathy reveals retinal capillary nonperfusion and “pruning” of several branches of the temporal retinal arterioles.

The fluorescein angiogram of the same patient shows marked enlargement of the foveal avascular zone with significant ischemia. A few scattered microaneurysms are noted.