Per the storyline, WWE says that Mysterio’s vision is improving slowly each day and his optic nerve is intact. There is no timeline for Mysterio’s return at this time, according to WWE.
As noted on Wrestling Observer Radio by Dave Meltzer, the last real-life update on Mysterio is that he had not yet signed a new contract with WWE. If Mysterio signs a new deal then he would resume his storyline with Seth Rollins.
Mysterio met with Vince McMahon last week at WWE Headquarters in Stamford, CT. It is widely believed that he will end up singing a new deal to stay with the company. Part of the reason why everyone thinks he will stay is that he wants to launch his son Dominik’s career in WWE.