Do these glasses actually block blue light?

The lenses are described as an anti-blue-light filter, but no blocking percentage or wavelength range is published. Without that figure, you cannot compare the filter strength with rival screen glasses that state their cutoff.

Can I wear them over contact lenses?

Yes. They are non-prescription glasses, so they sit in front of your eyes like any pair of frames and work alongside contacts. They will not replace a prescription if you need vision correction.

Will they help me sleep better?

The brand claims the lenses support natural melatonin production by cutting evening blue light. That effect depends on how much blue light the lenses block, which is not disclosed, so expect modest help at best and pair them with reduced screen time before bed.

Do they protect against UV rays?

Yes, the lenses carry UV400 protection, which covers the full UVA and UVB range. That makes them usable outdoors as well as at a desk.

Are the lenses scratch resistant?

The lenses have a scratch-resistant coating, which helps against everyday wear. It reduces scratching rather than preventing it, so store them in a case.

Are they prescription glasses?

No. They are non-prescription anti-blue-light glasses. If you need vision correction, you would need a prescription pair with a blue-light coating instead.