Shares of Second Sight Medical Products Inc. made some major gains Tuesday, jumping more than 20 percent during trading hours before falling back to a nearly 18-percent gain by market close.

Shares of the Sylmar medical devices firm, which makes a prosthetic vision device called the Argus II, have risen nearly 66 percent over the past six months. The company recently announced it had implanted the Argus II into two patients in Iran in keeping with its goal of expanding into global markets.

Second Sight stock (EYES) rose 35 cents, or 17.5 percent, on Tuesday to close at $2.35 on the Nasdaq.