Sub-tenon Versus Sub-conjunctiva Anaesthesia for Intraocular Surgery

Abstract

Objective: To compare the pain relief achieved using sub-Tenon anesthesia with that of sub-conjunctival anesthesia technique in intraocular surgery at the Guinness Eye Centre Onitsha Nigeria. Materials and Methods: Consecutive adult patients who had intraocular surgery under local anesthesia were randomized into having sub-Tenon (3 mL) or sub-conjunctival (0.5 mL) injections using xylocaine ± adrenaline. The manual suture-less surgery technique was used for cataract surgery alone and cataract surgery with pterygium excision; the extra-capsular cataract extraction technique was adopted for combined trabeculectomy and cataract surgery. Surgery duration was recorded. Patient’s pain perception graded as none, mild, moderate or severe. Results: 100 patients made up 51 (51.0%) males and 49 (49.0%) females, age range was 31–88 years, median – 68 years, participated. Sub-Tenon anesthetic technique was used in 52 (52.0%) and sub-conjunctival in 48 (48.0%) participants. Seventy-eight (78.0%) patients had cataract surgery; 10 (10.0%) had trabeculectomy; 7 (7.0%) had combined trabeculectomy and cataract surgery and 5 (5.0%) had pterygium excision with cataract surgery. The mean surgery duration in the sub-Tenon anesthesia group was 31.8 ± 8.5 minutes and 30.2 ± 9.8 minutes in the sub-conjunctival group (P > 0.05). Fifty (96.2%) patients in the sub-Tenon group and 38 (79.2%) in the sub-conjunctival group experienced mild or no pains; 2 (4.2%) patients in the sub-Tenon group and 10 (20.8%) in the sub-conjunctival group experienced moderate to severe pains (P < 0.05). Conclusions: Both sub-conjunctival and sub-Tenon anesthetic achieved effective analgesia in intraocular surgery. But sub-Tenon anesthesia is significantly associated with lower incidence of severe pains.