Best vitelliform macular dystrophy (BVMD) may be diagnosed based on the findings on an exam of the fundus (the interior surface of the eye opposite the lens); an electrooculogram (EOG); and the family history. An eye exam may include other tests as well. A fundus exam may show a typical yellow yolk-like macular lesion. An EOG is usually abnormal in affected people, but occasionally, people with signs of BVMD and a mutation in the BEST1 gene have a normal EOG. The family history in affected people is often consistent with either autosomal dominant or autosomal recessive inheritance. Genetic testing may also be used to make a diagnosis of BVMD. A BEST1 mutation is detected in about 96% of affected people who have an affected family member. In people with no family history of BVMD, the mutation detection rate ranges between 50-70%. The exact type of genetic test ordered to confirm a diagnosis may depend on a persons ancestry, family history, and/or whether other eye disorders are also being considered. 
How to diagnose Best vitelliform macular dystrophy ?