Do pinhole glasses help for poor vision?

Not really: Pinhole glasses are used to determine if improved lenses can help someones vision. It can help you see better if you do not have eyeglasses but since it cuts down a substantial amount of light, it is not useful for ordinary vision.

Not really: Pinhole glasses only allow the straight or incident beams of light through the aperture. This is the same principal as the pinhole camera. The downside is that there is very little light that gets through. So, they can help you with focus if you don't have glasses. Glasses work better but require an eye exam. Good luck.

Sometimes: If the reason for your poor vision is a refractive error (i.e., can be corrected with glasses), then many times pinhole glasses can improve vision. The reason is that the pinhole only lets one ray of light through a hole, so there is theoretically no focal point where multiple light rays converge, and thus the single ray is 'in focus' at any point along it. They don't work for cataracts, etc.