Illustration by David Navascues

“Ciba Vision has combined the peanut butter and the chocolate,” says New York opthamologist Barry Farkas, referring to the company’s Focus Night & Day contact lenses, the first designed for continuous 24-hour, 30-day use. The lens is a hybrid of an oxygen-permeable silicon lens (the peanut butter) and a more comfortable soft lens (the chocolate). Under Farkas’ care, two Popular Science editors tested Ciba’s claims.

Staffer A suffers from dry eye, but after a couple of days, she was wearing the lenses in comfort overnight. They lasted the full month-she never took them out. Staffer B suffers from an allergic eyelid and blood-vessel growth into the cornea. She wore the lenses a few times overnight, but in the end opted to take them out each night. The lenses lasted for 3 weeks; during that time, the increased oxygen to her eyes had diminished vessel growth. Both staffers have since made them their everyday lens.