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Ophthalmology – Choroidal Folds
Choroidal folds are parallel striae seen at the posterior pole of the eye and may be oriented horizontally, vertically, or obliquely. They are not a disease themselves but rather a clinical sign that can be idiopathic or associated with a variety of ocular, orbital, or systemic conditions. Their presence should always prompt evaluation for an underlying cause.
The exact epidemiology of choroidal folds is unknown. They may occur in a wide range of patients depending on the associated underlying condition. Since they are often asymptomatic, many cases may go undetected unless identified during routine fundus examination.
The pathophysiology involves wrinkling of the retinal pigment epithelium (RPE), Bruch’s membrane, and inner choroidal layers. This is believed to result from an imbalance between forces acting on the globe. These forces may be internal, such as hypotony, or external, such as orbital masses or increased intracranial pressure. Direct tractional forces, for example from choroidal neovascular membranes, can also contribute. The characteristic appearance of alternating light and dark bands reflects structural changes in the RPE and choroid.
Etiologically, many cases are idiopathic, but secondary causes are common and must be considered. Ocular causes include choroidal tumors, neovascularization, inflammation, hypotony, posterior scleritis, uveal effusion, central serous chorioretinopathy, and prior scleral buckle surgery. Optic nerve-related causes include papilledema and optic nerve tumors. Orbital conditions such as tumors, inflammation, or thyroid eye disease may also lead to folds. Additionally, increased intracranial pressure alone can produce choroidal folds, even in the absence of papilledema.
Clinically, patients may be asymptomatic or may report blurred vision or metamorphopsia. On funduscopic examination, choroidal folds appear as alternating light (yellow) and dark (orange) parallel lines at the posterior pole. A comprehensive ocular examination, including intraocular pressure measurement, is essential to help identify any underlying pathology.
Diagnostic imaging plays an important role. Fluorescein angiography typically demonstrates an alternating pattern of hyperfluorescence and hypofluorescence corresponding to stretched and compressed areas of the RPE. Optical coherence tomography (OCT) can clearly show undulations of the RPE and helps differentiate choroidal folds from retinal folds. Fundus autofluorescence may also provide supportive findings. If an underlying cause is suspected, further orbital imaging such as B-scan ultrasonography, CT, or MRI may be required.
Management of choroidal folds is directed toward treating the underlying cause. In cases where no cause is identified and the patient is asymptomatic, observation with periodic follow-up is appropriate. Serial fundus examinations are recommended to monitor for changes or the emergence of an underlying condition.
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