Shares of Second Sight Medical Products Inc, a maker of artificial retinas designed to partially restore sight to the blind, more than doubled in their market debut.

The stock touched a high of $22.45 on the Nasdaq on Wednesday, valuing the company at $777.3 million.

Second Sight’s Argus II System – the world’s only approved retinal implant – treats outer retinal degenerations, a hereditary disease affecting an estimated 1.5 million people worldwide.

The company’s net loss increased to $21.6 million in the nine months ended Sept. 30 from $17 million in the same period last year.

Second Sight offered 3.5 million shares priced at $9 each, raising $31.5 million.

The stock was up 120 percent at $19.80 after about an hour of trading, with about 1.6 million shares exchanged.

MDB Capital Group LLC was the lead underwriter for the offering.