Sylmar medical device firm Second Sight Medical Products Inc. has appointed Gregg Williams, the company’s largest shareholder, as chairman of its board of directors. Williams succeeds Dr. Robert Greenberg, who has led the board since August 2015 and will continue to remain a member. Williams joined the board in June 2009; he is the chief executive of Williams International Inc., an aviation turbine manufacturer in Michigan. Second Sight manufactures and sells implantable devices to restore a functional form of vision in blind patients. The company’s main product is a prosthetic retina called the Argus II, which is marketed in both the U.S. and Europe. Clinical trials on a second product – a prosthetic cortical implant – are currently underway. Second Sight shares rose 6 cents, or 3.2 percent, on Friday to close at $1.96 on the Nasdaq.