The retina is a delicate, light-sensing layer of tissue located at the back of the eye. This thin membrane receives visual data and converts it into electrical signals that travel to the brain via the optic nerve. A retinal fold is a wrinkle or crease in this tissue that disrupts the retina’s normally smooth, flat surface. This distortion can have significant implications for visual clarity, often requiring medical evaluation.
Understanding Retinal Structure and Function
The retina’s function relies on its precise architecture remaining flat against the inner wall of the eye. The macula, located centrally, is responsible for sharp, detailed central vision necessary for tasks like reading. The fovea, within the macula, contains the highest concentration of photoreceptor cells that capture light and color.
Clarity depends on light rays hitting these photoreceptors in an organized fashion. When a fold develops, it throws the retinal tissue out of alignment, creating peaks and troughs. This warping causes light to scatter or strike the photoreceptors at incorrect angles. The brain interprets this distorted signal as wavy lines or blurred vision, known as metamorphopsia.
The retina is supported by the vitreous humor, a clear, gel-like substance filling the main cavity of the eye. Any force that pulls on, compresses, or causes redundancy in this delicate tissue can lead to a crease that compromises image processing.
Common Causes of Retinal Folding
Retinal folds arise from mechanical forces that pull the tissue, compress the eyeball, or cause tissue redundancy. One frequent mechanism is vitreoretinal traction, where the vitreous gel pulls abnormally on the retina. The vitreous naturally liquefies and shrinks with age, usually detaching cleanly in a process called posterior vitreous detachment.
If the vitreous remains attached to the macula, it exerts a tugging force, leading to vitreomacular traction. This pulling causes the retina to wrinkle. Traction also occurs in proliferative diseases, such as advanced diabetic retinopathy, where scar tissue contracts and pulls the retina into folds.
Other causes involve pressure changes affecting the globe’s shape. Ocular hypotony (abnormally low intraocular pressure) often occurs following eye surgeries, causing the scleral wall to collapse inward and forcing the retina into folds (hypotony maculopathy). Conversely, external forces like an orbital mass (tumor or swelling) compress the globe. This external pressure causes the inner layers to buckle into characteristic parallel undulations known as chorioretinal folds. Trauma, such as blunt force injury, is another direct cause.
Identifying Retinal Folds Through Examination
An ophthalmologist identifies retinal folds using a comprehensive eye examination and specialized imaging tools. Initial examination involves a direct view with an ophthalmoscope, where folds appear as alternating light and dark streaks that are often curvilinear or parallel.
The most definitive diagnostic tool is Optical Coherence Tomography (OCT), which provides a high-resolution, cross-sectional view of the retina’s layers. OCT clearly illustrates the peaks and troughs, differentiating between full-thickness and partial-thickness folds. This imaging also reveals the underlying cause, such as residual vitreous attachment or choroidal thickening.
Fundus photography is used for documentation and monitoring. If the cause is suspected to be external (e.g., an orbital mass or inflammation), imaging techniques like ultrasound or magnetic resonance imaging (MRI) of the orbit may be necessary. The specific pattern and location of the fold help guide treatment selection.
Management and Treatment Approaches
Management depends on the underlying cause and the extent to which the fold impacts central vision. For minor, peripheral folds that do not affect the macula, observation is employed. Folds caused by transient swelling or inflammation may resolve spontaneously as the underlying condition improves.
If the fold is caused by an underlying medical issue, treatment focuses on resolving that issue, such as treating inflammation or normalizing intraocular pressure in hypotony maculopathy. When the fold is caused by traction, such as from an epiretinal membrane, surgical intervention is often required, typically a pars plana vitrectomy.
During a vitrectomy, the surgeon removes the vitreous gel and any membranes or scar tissue exerting pulling force. Specialized techniques, such as peeling the internal limiting membrane (ILM), relieve tension and allow the retina to flatten. In complex cases, a temporary internal tamponade agent (gas or silicone oil) may be injected to hold the retina flat while it heals.