However, the Science Marches on Department has kindly brought my attention to a similar case that actually got published in a medical journal!
Yes, folks, here is the story of a lady with visual loss. After a work up found no clear cause, they discovered they could fix the problem simply by holding up her eyelids with tape.
Unfortunately, the abstract doesn't clarify what kind of tape. How would masking vs. Scotch vs. duct tap compare for this? Clearly, more extensive studies are needed.