How Daniel Key's Injuries Affect His Vision

Daniel Key suffered injuries to his eyes, lacerations to his head that required 103 stitches and three broken fingers on each hand. He was able to regain his sight and I think for the most part had a full recovery. Now considering how this attack unfolded, the perpetrator was already, as we know, in the victim's home. How did he get in? Did he have prior access and could those answers provide any clues to maybe who he was? Or was this a burglary in progress that was interrupted by a homeowner?