ANGIOID STREAKS

Angioid streaks are characteristic linear, narrow subretinal streaks that radiate from a peripapillary area to the macula and midperipheral fundus. Angioid streaks typically appear in the second decade and are usually bilateral. They may be associated with systemic disease in approximately 50% of patients. Visual loss usually results from secondary choroidal neovascularization (CNV).

Symptoms

Patients with angioid streaks are usually asymptomatic. Visual symptoms arise secondary to CNV in about 50% of eyes. The presence of CNV is heralded by decreased vision, central scotoma, and metamorphopsia.

Clinical Features

Angioid streaks are linear, subretinal streaks that radiate from a peripapillary region to the macula and midperipheral fundus. The streaks are usually bilateral and may be variable in appearance. Streaks range in color from reddish brown and gray to yellow. About 10% of patients have diffuse angioid streaks that radiate concentrically as well as radially, producing a “cracked eggshell“ appearance. The streaks may widen and lengthen with time. About one third of patients have a diffuse mottling of the fundus, termed a peau d’orange appearance.

Choroidal neovascularization may occur with angioid streaks. Choroidal neovascularization is suggested by the presence of subretinal fluid and subretinal hemorrhage. Subretinal hemorrhage without CNV may also occur along the angioid streaks with minor ocular trauma.

Ancillary Testing

Fluorescein angiography is performed in patients with suspected CNV. Usually, CNV is detected in the macula along the track of an angioid streak. The fluorescein pattern of angioid streaks is variable. The streaks may hyperfluoresce early and stain in the late phase of the study.

Pathology/Pathogenesis

Angioid streaks represent full-thickness breaks in Bruch’s membrane with disruption of the underlying choriocapillaris and the overlying retinal pigment epithelium (RPE). Bruch’s membrane is thickened and basophilic, with evidence of calcium deposition.

The pathogenesis of angioid streaks is unknown. Calcification and a loss of elasticity of Bruch’s mem-

brane may lead to ruptures of Bruch’s membrane with minor trauma or due to the forces exerted by the extraocular muscles on the globe. Disruption in Bruch’s membrane may result in the development of choroidal neovascularization.

Treatment/Prognosis

Laser therapy has been used to treat CNV developing in association with angioid streaks. Laser photocoagulation techniques similar to those used for the treatment of CNV associated with age-related macular degeneration (AMD) have been studied. Visual loss may be stabilized in patients with successfully treated membranes. Most case series demonstrate a high rate of recurrence of CNV. Photodynamic therapy (PDT) may be effective

in reducing the risk of visual loss in patients with subfoveal CNV.

Systemic Evaluation

Angioid streaks may occur in association with several systemic diseases. In one series, 50% of patients with angioid streaks had evidence of systemic disease.

Pseudoxanthoma elasticum is an inherited disorder of connective tissue characterized by papular and reticular skin changes, producing a “chicken skin” appearance. Patients may also suffer from occlusive vascular disease, upper gastrointestinal hemorrhage, and hypertension. Paget’s disease of bone is characterized by gross deformities of the skull, spine, and pelvis due to coarsely thickened and sclerotic bone. Angioid streaks may also be seen with sickle cell disease, lead poisoning, EhlersDanlos syndrome, and abetalipoproteinemia.

Systemic evaluation may include skin biopsy (pseudoxanthoma elasticum), radiographs (Paget’s disease of bone), hemoglobin electrophoresis (sickle cell disease), and serum lead levels.

This fundus photograph reveals multiple angioid streaks radiating from the optic disc in a woman with pseudoxanthoma elasticum. Note the subretinal location of the streaks.

This 42-year-old woman with pseudoxanthoma elasticum was found to have multiple angioid streaks in each eye. Her right eye had prominent peripapillary streaks and one streak extending through the macula with atrophy in the fovea.

The fellow eye of the same patient reveals multiple angioid streaks and subfoveal hemorrhage suggesting the presence of choroidal neovascularization.

Same patient approximately 3 years later. She presented with sudden visual loss related to choroidal neovascularization with subretinal hemorrhage along the margin of the angioid streak.

Visual loss in patients with angioid streaks is usually related to the development of choroidal neovascularization. Fibrovascular proliferation commonly results in the formation of a macular scar.

This patient developed subretinal hemorrhage following incidental eye trauma. Also note the “peau d orange” pigment mottling in the temporal macula.

Central serous chorioretinopathy (CSC) is characterized by self-limited localized serous retinal detachments of the macula. Central serous chorioretinopathy usually occurs in young individuals, with a male preponderance of 8:1. Although typically unilateral, CSC may be bilateral. Common associations include stress, type-A personality traits, hypertension, and headache. Central serous chorioretinopathy is most commonly idiopathic but has been described with pregnancy, systemic lupus erythematosus (SLE), hemodialysis/organ transplantation, and other hypercortisolemic states, including exogenous corticosteroid use and Cushing’s syndrome.

Symptoms

Patients with CSC present with visual blurring, distortion, micropsia, and an area of visual darkening (positive scotoma).

Clinical Features

Visual acuity may be decreased to a variable degree. Approximately 50% of patients with CSC retain better than 20/30 visual acuity. Subretinal fluid produces a hyperopic shift in the patient’s refraction. Amsler grid testing often reveals central or paracentral distortion. Macular examination demonstrates a localized oval or round area of subretinal fluid. Some cases may have an associated retinal pigment epithelial (RPE) detachment. Retinal pigment epithelial alterations are observed commonly in both eyes.

Retroretinal precipitates on the back surface of the retina also may be observed. The presence of subretinal fibrin suggests very active leakage and is more common with pregnancy, SLE, or corticosteroid use. Resolved episodes of CSC may produce mottled changes in the RPE. Atypical findings include inferior, dependent RPE atrophic tracks from prolonged, recurrent serous detachments, multiple bullous serous retinal detachments associated with subretinal fibrin and shifting subretinal fluid, and choroidal neovascularization (CNV).

Ancillary Testing

Fluorescein angiography demonstrates a focal leakage point in the early phase of the angiogram with pooling of fluorescein in the subretinal fluid in the later phases of the angiogram. About 30% of patients have more than one leakage point evident. Recurrent leakage points tend to occur within 1 mm of the previous leakage points.

In approximately 10% of cases, a classic “smokestack” pattern of hyperfluorescence is observed. Transmission or “window” defects are common in both eyes.

Indocyanine green angiography demonstrates choroidal hyperpermeability.

Pathology/Pathogenesis

The precise pathogenesis of CSC is not completely understood. Central serous chorioretinopathy is most likely the result of increased capillary permeability in the choriocapillaris. Why choriocapillaris hyperpermeability develops is unclear. Central serous chorioretinopathy has been produced in monkeys following daily intravenous injections of epinephrine; the adrenergic effect of epinephrine may cause damage to the choriocapillaris and subsequent choriocapillaris hyperpermeability. The disorder has been observed in various hypercortisolemic states including exogenous corticosteroid use, Cushing’s syndrome, pregnancy, SLE, and hemodialysis/organ transplantation. Cortisol may influence the constrictive action of catecholamines on arterioles; cortisol also may contribute to hypertension and increase capillary fragility.

Treatment/Prognosis

The majority of cases of CSC are self-limited with a duration of approximately 6 weeks. The prognosis for visual recovery is excellent, with 90% of patients recovering 20/30 or better visual acuity. Focal laser photocoagulation has been demonstrated to hasten the resolution of subretinal fluid but has no clear effect on long-term visual prognosis. In general, focal laser treatment is reserved for patients with persistent subretinal fluid for more than 4 months, occupational requirements for earlier visual rehabilitation, or development of degenerative changes in the area of detached retina. A well-defined leakage point greater than 500 mm from the center of the foveal avascular zone should be present. A light-intensity burn is placed over the leakage site.

Although some evidence indicates that laser treatment may reduce the recurrence rate of CSC, no randomized trials have confirmed this observation. Due to the potential complications of laser photocoagulation including a paracentral scotoma or secondary CNV, laser therapy continues to be reserved for chronic cases. Recurrent episodes of CSC are observed in 30% to 50% of patients. Most recurrences occur within 1 year of the initial episode.

Systemic Evaluation

Systemic evaluation should focus on possible precipitating factors such as corticosteroid usage, pregnancy, and hypertension.

Central serous chorioretinopathy is characterized by the presence of a localized oval or round area of subretinal fluid.

The presence of subretinal fibrin suggests very active leakage and is more common with pregnancy, systemic lupus erythematosus, and corticosteroid use.

During the early resolution phase of central serous chorioretinopathy, protein deposits may form on the posterior surface of the retina. Other common findings are pigment epithelial detachments and pigmentary alterations.

Dependent retinal pigment epithelial atrophic tracks result from prolonged, recurrent central serous chorioretinopathy. The tracts often originate in the peripapillary region and extend inferiorly; macular involvement is associated with visual loss.

The typical fluorescein angiographic finding of central serous chorioretinopathy is a single hyperfluorescent spot that increases in size and intensity throughout the study.

Late-phase fluorescein angiographic image of the same patient reveals increased size and intensity of fluorescein leakage.