what is the number one rated hospital for cataract surgery?

Assuming you are looking for hospitals in the U.S., here is the information I found below.

According to the U.S. News, the Best Hospitals for 2011 in Ophthalmology can be found at this site: http://health.usnews.com/best-hospitals/rankings/ophthalmology (it is not listed by specific surgery, unfortunately).

Another source for the "100 Top Hospitals" can be found here: http://www.100tophospitals.com/top-national-hospitals/index.html#winners.

These are two great places to begin your research, and beyond the "best hospital", you would also want to make sure the surgeon you choose within the hospital is experienced with this specific surgery, and don't underestimate your personal rapport with this person... you need to feel comfortable asking questions, receiving answers and feel that you are an important patient to a caring and trusted doctor.