A friend has a Batman nightlight that projects Batman onto her ceiling. She has vision problems because of a head injury. She could see Batman fine when she was in an upstairs bedroom and the ceiling was higher. She has had to move downstairs to a smaller room with a lower ceiling. She can no longer see Batman. She sees a blob of light. Is there some lens I can project the image through that would make Batman smaller so that she can see that it's actually Batman? Or bigger? I might need to try it both ways to see which works.
Finding a special lens will be difficult and complicated. Get a extension cord and plug the nightlight into it. Now shine the image the on the walls or ceiling until you obtain an image your friend can see and enjoy. Find a way to mount the light in that location. That's what I would do. Good luck.