Are these a dark brown or a medium brown? They look dark in the picture.

The front of the frame is a medium brown color.

How long does it take to get these with a prescription added?

The frame is currently in stock, and available to ship out immediately. Lab processing time varies, depending on the prescription. Please contact customer support for assistance. 1800.217.2020

Can't answer that--frames without the Rx were delivered relatively quickly.WARNING: These frames chip very easily. (Not the lens--the finish). We've had 2 pairs and both did the same thing in just a few months of normal use. Not recommended.