The views when a cup is full are different in different cultures. I found out that as a Stargardter I can get into an insoluble situation when filling a cup.
What Is Stargardt Disease?
Stargardt Disease (STGD) - American Academy of Ophthalmology
PDF) Antioxidant Saffron and Central Retinal Function in ABCA4-Related Stargardt Macular Dystrophy
Atlas Entry - Stargardt disease
Glasses for Stargardt's Disease
Avoid Misdiagnosing Late-Onset Stargardt's Disease for AMD
How Much Do You Know about Stargardt Disease?
Stargardt disease - Macular Society
Monitoring and Management of the Patient with Stargardt Disease