Hi Anders, great question! In terms of the actual heat, there isn't a problem that has ever been recorded, trialled or that we've ever heard about. That is for the naked eye, of course, wearing contacts becomes a different recommendation for obvious reasons. In terms of the type of light wavelengths affecting the eyes, a recent study has looked at Red Light Therapy for degenerative eyesight with very interesting results (redlightrising.co.uk/2021/12/28/red-light-therapy-for-eye-health-updated/?inf_contact_key=45c08220379062aa152841c9a8c4bd58680f8914173f9191b1c0223e68310bb1) I hope that helps at all?

Is it okay to wear contacts in the sauna?

those studies are actually dry saunas

Most sauna studies have been conducted with traditional saunas due to the length of time they've been around, however, the primary source of therapeutic benefits comes from raising the core body temperature and creating heat stress for the body's physiological response. Therefore, to mimic studies you want a hotter temperature sauna and the hottest infrared saunas are full-spectrum saunas. Please keep in mind that many of the sauna studies have been conducted in traditional saunas.