“Eyeglasses worn on a daily basis can be worn for the photo. However, there should be no reflections from the eyeglasses that obscures the eyes,” but “dark glasses or nonprescription glasses with tinted lenses are not acceptable unless you need them for medical reasons. A medical certificate may be required.”

Often it’s the case of a photographer getting glare off the glasses from his/her flash. The trick here is to tilt your glasses downards, putting the stems of the glasses halfway up your head. It feels really weird, but it looks normal on the photo, and the flash light is reflected downwards instead of back at the camera.

p.s. — I don’t know if it’s the case everywhere, but I was required to have my recent U.S. passport photo taken with my glasses off.