Diagnosis and Imaging in Stargardt Disease

The journey to a Stargardt diagnosis often involves moving beyond standard eye charts and basic exams. Because the disease affects the microscopic layers of the retina, doctors use a suite of specialized imaging and functional tests to “see” what is happening beneath the surface ^[1][2].

Visualizing the Retina: FAF and OCT

Standard eye exams look at the “surface” of the retina. However, Stargardt disease is characterized by changes deep within the tissue that require advanced technology to detect.

Fundus Autofluorescence (FAF)

This is perhaps the most important imaging tool for Stargardt disease. It uses a specific wavelength of light to make certain substances in the eye glow (fluoresce) naturally ^[3].

• The “Glow” of Waste: FAF can see lipofuscin—the fatty waste product that builds up in Stargardt disease ^[4].
• Flecks and Spots: On an FAF scan, doctors look for “flecks” (bright spots of lipofuscin buildup) and “atrophy” (dark spots where cells have died) ^[4][5].
• Patient Experience: This test is non-invasive and feels like having a high-flash photograph taken of your eye. No dyes are injected ^[6].

Optical Coherence Tomography (OCT)

If FAF is like taking a photo, OCT is like taking a cross-section or an “ultrasound with light.” It provides a 3D view of the retinal layers ^[7].

• Monitoring Health: Doctors use OCT to check the ellipsoid zone, a specific layer of the photoreceptors. In Stargardt, this layer often thins or breaks down over time ^[8].
• Structural Integrity: OCT helps doctors see the physical thickness of the macula, which is critical for tracking how the disease is progressing ^[7].
• Patient Experience: You simply look into a lens and stay still for a few seconds while a light scans your eye. It is painless and does not touch the eye ^[9].

Measuring Function: The ERG

While FAF and OCT look at the structure of the eye, an Electroretinogram (ERG) measures how well the eye is actually working ^[10].

• Electrical Signals: An ERG measures the electrical response of your light-sensing cells. It can determine if the problem is limited to the center of the eye (the macula) or if it involves the entire retina ^[11][12].
• Prognosis: ERG results are a powerful predictor of how the disease may behave in the future. A “normal” full-field ERG often suggests a better long-term visual outlook for the peripheral vision ^[11].
• Patient Experience: Small sensors are placed near the eye (sometimes on the skin or as a specialized contact lens). You will look at flashes of light in both dark and light settings. It can take about 45–60 minutes.

The Role of Genetic Testing

Imaging is excellent for showing what is happening, but genetic testing explains why ^[13]. Because Stargardt can look like several other conditions—such as cone-rod dystrophy or PRPH2-related diseases—finding the specific mutation in the ABCA4 gene is the “gold standard” for a definitive diagnosis ^[2][14].

By combining these tests (multimodal imaging), your care team can create a complete map of your eye health. To properly monitor changes in the retina, doctors generally recommend repeating non-invasive imaging scans like FAF and OCT at regular intervals, often every 6 to 12 months, depending on the stage of the disease ^[10][15].