Metamorphopsia is a visual distortion that causes straight lines to appear wavy or bent. It is not a standalone disease but a symptom of an underlying issue affecting the eye or, in some cases, the brain. This distortion stems from problems with how the eye processes images, which can make everyday activities like reading or recognizing faces more challenging.
Symptoms and Visual Distortions
The primary symptom of metamorphopsia is seeing straight lines as curved or wavy. This is often first noticed when looking at objects with a grid pattern, like window blinds or a tiled floor. For instance, a rectangular door frame might seem to twist, or a telephone pole may look bent. This distortion affects the central field of vision, while peripheral vision remains normal.
Beyond wavy lines, objects might appear smaller (micropsia) or larger (macropsia). Some individuals report that flat objects look rounded or that the borders of items seem smudged. These symptoms can develop suddenly or gradually and may affect one or both eyes.
Underlying Medical Causes
Metamorphopsia is most frequently linked to conditions affecting the retina, specifically the macula. The macula is the central part of the retina responsible for sharp, detailed vision. Any change to its flat surface, such as wrinkles or swelling, can disrupt the light-detecting cells and cause the visual distortion.
A common cause is age-related macular degeneration (AMD). In the “wet” form of AMD, abnormal blood vessels leak fluid or blood, altering the macula’s shape. Another cause is an epiretinal membrane, a thin layer of scar tissue that forms over the macula and causes it to wrinkle. A macular hole, which is a small break in the macula, can also lead to distorted vision.
Other retinal issues can also trigger these symptoms. Diabetic retinopathy can cause fluid to accumulate in the macula, a state known as macular edema. A retinal detachment, where the retina pulls away from its normal position, is another serious cause of distortions. In rarer cases, metamorphopsia can be associated with migraines with aura or other brain conditions that affect visual processing.
Diagnosis and When to See a Doctor
Any new or worsening visual distortion requires a prompt visit to an eye doctor, as it can signal a serious medical issue. You can monitor for these changes at home with an Amsler grid, a square chart with a grid pattern and a central dot. Someone with metamorphopsia may notice the grid’s lines appear wavy, bent, or that parts of the grid are missing.
An ophthalmologist will conduct a dilated eye exam to get a clear view of the retina and macula. This allows them to look for abnormalities like fluid leakage, scar tissue, or holes. For a more detailed image, a non-invasive test called Optical Coherence Tomography (OCT) is often used. The OCT scanner creates a cross-sectional picture of the retina, allowing the doctor to see its layers and measure any swelling or structural changes.
Addressing Metamorphopsia Through Treatment
Metamorphopsia is managed by treating the underlying condition causing the symptom. The visual distortion itself is not treated directly; instead, interventions focus on resolving the problem within the retina or macula. Addressing the root cause can improve or stabilize the visual symptoms.
For instance, if wet AMD is the cause, treatment involves anti-VEGF medication injections to stop leaky blood vessels and reduce swelling. For an epiretinal membrane or a macular hole, a surgical procedure called a vitrectomy may be performed to remove scar tissue or repair the hole. If diabetic retinopathy has led to macular edema, managing blood sugar levels, laser treatment, or injections are the primary strategies.