How is Stargardt Disease Diagnosed?
Stargardt disease is relatively rare, and so it might not be the first thing you or your child’s eye doctor think of when complaints about vision first arise. Due to its slowly progressing nature, it might go unnoticed at first, so it’s important to report any changes in vision or any noticeable visual difficulties to the doctor. Based on reported symptoms, a doctor might do additional tests after an eye exam to rule out any other macular diseases or look for symptoms that correspond with Stargardt disease in order to come to an appropriate diagnosis.
Stargardt disease signs
A general eye exam will often find flecks of yellow fatty deposits, called lipofuscin, in the macula in a ring, wreath, or bullseye-like pattern.1 Some patients who have the fundus flavimaculatus variant of Stargardt disease may have flecks that are more broadly distributed throughout the retina rather than localized to the macula. Up to one-third of children with the disease will not have visible flecks, which also contributes to late diagnoses in many individuals.2
Stargardt disease diagnosis
An eye exam by an eye doctor will generally provide an idea of whether an individual has Stargardt disease, but there are a variety of tests that are done to fully assess the situation and determine the extent of the disease.1
Visual field testing
A visual field test can help objectively measure the field of vision and provide the doctor with an idea of how far out peripherally an individual can see and whether he or she has any blind spots.
In later stages, individuals with Stargardt disease may have impaired color vision. Color may be tested in many ways, however, the most common screening method involves the use of a book with colored numbers embedded in an image. Those with deficient color vision will not be able to make out the numbers on the page.
Essentially, fundus photography is a photograph of the retina. Serial photographs over the course of multiple visits may help doctors identify small progressive changes in the retina. However, lipofuscin deposits are not always seen with traditional fundus photographs.
This test involves a special laser camera that causes lipofuscin in the eye to “light up” or fluoresce, providing an image that highlights the density and extent of lipofuscin deposits underneath the retina.
Electroretinography is a test that measures the electrical response of cones, rods, and other cells in the retina in response to light. An abnormal electrical response may indicate an abnormality in the function or number of cells present in the retina.
Optical coherence tomography (OCT)
Optical coherence tomography (OCT) is similar to ultrasound, except this test bounces light waves off of retina to get cross-sectional or “sliced” images of the retina. This allows doctors to identify changes deep within the eye and is useful as a screening tool for a variety of retinal degenerations.
What can you do?
If you suspect your child has Stargardt disease, an eye doctor is the only one who will be able to provide you with an accurate diagnosis. They will be able to do a visual exam of the eye, and perform any other tests they deem necessary in order to rule out other possible diagnoses and reach an accurate diagnosis of Stargardt disease. Talk with your child’s doctor about your concerns, and any symptoms that are present.