In Best's disease, which measurement is more likely to be abnormal?

Best's disease, also known as Best macular dystrophy, is primarily characterized by an accumulation of lipofuscin in the retinal pigment epithelium and is linked to mutations in the BEST1 gene. This condition leads to a gradual progression of visual impairment primarily affecting central vision.

The electro-oculogram (EOG) is a test that measures the electrical activity of the retina. In patients with Best's disease, a characteristic abnormality is often observed in the EOG, specifically a reduced Arden ratio. This finding reflects the dysfunction of the retinal pigment epithelium, which is a key feature of the disease. The EOG is particularly sensitive to changes in the function of the retinal pigment epithelium, making it more likely to reveal abnormalities in individuals with Best's disease compared to other measurements.

On the other hand, while visual acuity may be affected as the disease progresses, it can sometimes remain relatively preserved in the early stages. The electroretinogram (ERG) is generally not significantly affected in Best's disease, as the outer retina (photoreceptors) is typically functioning well initially. Fundus examination findings can reveal characteristic lesions, but these may not always correlate with immediate functional deficits.

Thus, the