Antiobiotics during surgery

Why are antiobiotics given during cataract surgery?  I took antiobiotic drops before and after my two cataract surgeries for each eye, but for the second surgery I was billed almost $300 extra for antibiotics during surgery.  I did not have any pre-existing eye condition.

[John C Hagan III, MD, FACS, FAAO]

The most feared complication of cataract surgery is infection (endophthalmitis). To prevent it antibiotic drops are used during the preparation for surgery when the eye pupil is dilated. Some physicians inject antibiotics into the eye at the end of the case or under the conjunctiva or add it to the infusion line to the phacoemulsifier.

Also lest anyone have any misconception that cataract surgery is an expensive surgery: in the early 1980's Medicare paid the surgeon over $1800 for the surgery and 3 months of care. In 2007 Medicare pays $675 and falling fast. For reference that average cost of a tooth crown is over $1000. I am not exagerating by saying that if it falls any further the surgeon will lose money doing cataract surgery over just staying in the office. This greatly concerns me as it is making cataract surgery much less attractive to young surgeons already strapped with over $200,000 of debt by the time they finish their residency.

JCH III MD