Ditto was a company that sold software that enabled eyewear companies to sell their products online using virtual fitting. Originally Ditto was a retailer that sold designer prescription eyeglasses and sunglasses. The company was originally based in San Francisco, CA before moving to Oakland, CA in 2018. It used virtual fitting technology to let customers try on eyeglass frames from a computer. The technology measured a customer's face by homing in on pupils, ears, cheekbones, ears and other facial landmarks, and then produced images of dozens of different pairs of glasses that might be a good fit.