Stargardt Disease

Stargardt Disease
SYMPTOMS Progressive vision loss, Metamorphopsia, Central scotomas, Color vision deficiencies, Photophobia
SIGNS Bilateral
Early signs: Yellow, pisciform flecks at the level of the RPE that are confined to the posterior pole with Loss of the foveal reflex
Late signs: Perifoveal RPE mottling, RPE atrophy at the macula in a “bulls-eye” pattern, “Beaten bronze” appearance at the macula as the RPE continues to atrophy
With the presence of late signs, vision is anywhere from 20/200 to 20/400
WORK-UP Color vision (mild dyschromatopsia), Full eye exam with dilated retinal exam, Visual field (presence of central scotomas), OCT analysis of the macula (a thickened external limiting membrane is one of the first signs seen with eventual thinning of the outer retinal layers including loss of the photoreceptors), Fundus Autofluorescence, Fluorescein Angiography ("dark choroid" due to the accumulation of lipofuscin at the level of the RPE), Fundus photos, Infrared photos, Electrodiagnostic testing (ERG: Typically normal unless there is extensive RPE atrophy / EOG: Typically abnormal), Dark adaptation (abnormal), Watzke-Allen test, Macular photostress test, Amsler grid
TREATMENT Give take home Amsler grid in order to monitor for change
Recommend AREDS II vitamins
Avoid Vitamin A supplementation
Recommend genetic counseling for other family members
Monitor. No treatment is effective
If the patient develops poor vision, refer to low vision
FOLLOW-UP Patient should be seen back every 6 months
ETIOLOGY Typically an autosomal recessive macular dystrophy (can also be autosomal dominant) due to a mutation in the ABCA4 gene which leads to an increase in lipofuscin at the level of the RPE
Autosomal dominant Stargardt disease is associated with a mutation in the ELOVL4 gene
DIFFERENTIAL DX Cone dystrophy, Plaquenil maculopathy, Best disease
NOTES Stargardt disease is the most common inherited macular dystrophy
Onset is typically during the first or second decade of life
Stargardt disease is called fundus flavimaculatus when the yellow, pisciform flecks can be found throughout the retina including the mid-periphery (not confined to the posterior pole). The macula is less likely to be involved and these patients experience later onset of the disease with slower progression of vision loss compared to typical Stargardt disease.