Second Sight Medical Products Inc. has named John Blake as its new chief financial officer.

The Sylmar medical device firm, which has developed a prosthetic retina that can restore a form of vision in blind patients, appointed Blake to the position on Thursday. Blake replaces Thomas Miller, who resigned in June 2017 but agreed to remain with Second Sight until a successor was found, the company said.

Blake joins Second Sight from aTyr Pharma Inc., where he had been senior vice president of finance since 2015. Blake previously oversaw global financial planning and analysis at publicly traded medical device firm Volcano Corp., where he worked alongside Will McGuire – now president and chief executive of Second Sight – from 2013 to 2015.

Shares of Second Sight (EYES) was roughly unchanged on Thursday, closing at $1.96 a share on the Nasdaq.