The virtual keyboard on my tablet has a dark grey background and white letters, on my left eye they seem like extending upwards or like im seeing double like silhouette but not extreme, it gets better if I focus my eye, but its still there. Does happen with my right eye only if I purposefully reduce my focus to see unsharp, and with white background it doesn't happen with any eye. Also happens with series with lots of dark, if I don't focus my eye all the time it gets washed out and the light somewhat flashes in
Don't know if this helps but my right eye is noticeably shortsighted, even though an optometrist gave me a 20/20 3 years ago (Im 20), wasn't a very accurate test I guess. And my left eyes vision has always been darker, though I read this is nothing out of the ordinary.