Are glasses really an obstacle? Man how far this szene has got rotten *ironic mode off*
Okay, if you need theses glasses, i mean if you have no sight at all without them, then you need to wear them. As suggested, just take it off for photographs. However, I would say "keep them on", because this could be THE difference between YOUR Nurse Joy and others. I try to keep a personal touch on every cosplay I do, for instance, my archangel Michael Cosplay from Angel Sanctuary. You never find these particular clothes in the Manga, however, I was recognized very often, because of the details. I didn't wear a string vest, but a plain black shirt, and patent leather pants, and some boots, and - of course - goggles. However, everyone knew "Hey, there's Michael", and yeah, it was no cosplay based on a official picture, but my own personal cosplay.
So why not trying a Nurse Joy with glasses?