I had cataract surgery on one eye in the UK last year. After the surgery I was directed to another room where I was asked a few questions. After about 10 minutes, I asked the lady how long it would be before I could leave. She replied I could leave right away if I felt okay and so I did. No tea and biscuits. I was on a bus 10 minutes later. I was told to get in touch if I had any major problems. There was no follow up test the next day. A watery eye for a few days and eye drops 4 times a day for 2 weeks, then 3 times a day for a week and then twice a week. An examination one month after surgery. However, is the doctor suggesting that you have both cataracts done at the same time? (which I would advise against) That may be a possible reason to stay overnight.