More than a hundred years ago, sub-Tenon’s anesthesia was used by Turnbull to perform enucleation. Nevertheless, retrobulbar injection has become the preferred technique of local anesthesia for ocular surgery.

Though it is easy to learn and easy to perform, it has numerous unavoidable complications. The report of the Joint Working Party on Anesthesia in Ophthalmic Surgery by the Royal College of Ophthalmologist (March 1993) has shown that life threatening administered and serious complications occurred in 1:360 cases.

Julian D Stevens introduced a curved sub Tenon Cannula in 1993 for placement of local anesthesia in the sub-Tenon’s. This has popularized the technique of sub-Tenon’s anaesthesthesia in recent years. I have designed a modified sub-Tenon’s cannula for the placement of anesthetic solution into sub-Tenon’s space