I speak from experience when I say that, regardless of what your optometrist tells you, it's a REALLY good idea to take your contacts out every night, even if they're soft disposables. I had left mine in for about a week (they were good for 15 days), and woke up in the middle of the night with searing pain in my sockets. Stumbled into the bathroom to sort it all out, flipped the light switch, and... nothing.

Long and short, I was 90%+ blind for two whole days. Went to the emergency room, where they discovered that the lenses had managed to work a small circular divot in the whites of my eyes around my iris, effectively "spraining" them to the point where my pupils became, err... fixed into the fully dilated position. My vision was slow to recover, I was ridiculously photosensitive for weeks afterwards, and my eyes have never been fully the same since.

On the plus side, I got to stay home from work for two days and drink beer in the dark accompanied by a completely random assortment of selections from my music collection. 'Twas surprisingly relaxing.

Isolated incident? Not according to the emergency room attenadants and the battery of eye specialists that I saw in the following week. Food for thought, just my $.02, your mileage may vary, etc.

Glasses por vida.