Cefazolin-Lidocaine Combination Solution to Reduce Antibiotic Pain

In retinal surgery, endophthalmitis is a sight-threatening eye infection that could complicate patient vision after the operation. At Toronto Western Hospital, for retinal surgery (operating at the back of the eye) it is common practice to administer an antibiotic (cefazolin) at the end of surgery, to reduce the risk of post-operative endophthalmitis. The antibiotic is administered by injection underneath the part of the eye called the conjunctiva. However, this antibiotic injection is often associated with high levels of post-operative pain. Previous studies have observed a reduction of this pain by injecting an anesthetic (lidocaine) in the subconjunctival space before the antibiotic. This study will seek to examine whether mixing 2% lidocaine with cefazolin before its injection will reduce post-operative pain in the retinal surgery setting.