Adequate anesthesia is a cornerstone of cataract surgery. Several techniques have been used, including retrobulbar anesthesia, peribulbar anesthesia, sub-Tenon's anesthesia, intracameral anesthesia, and topical anesthesia.1 The first 3 techniques have the advantage of achieving akinesia over the other 2 techniques.1 Of the 3 techniques, sub-Tenon's anesthesia is gaining popularity because of the ease of administration and the reduced incidence of globe perforation.2 However, a disadvantage of the technique is subconjunctival hemorrhage during the conjunctival incision. This is often alarming to patients and causes dissatisfaction with the surgery. Several methods may be used to reduce this complication: the use of phenylephrine to constrict the blood vessels and the avoidance of blood vessels by carrying out the conjunctival incision under the microscope. However, neither method is foolproof. The constricted blood vessels may still bleed when cut, and microscopic visualization may not avoid vessels that are too small to visualize.
We propose an easy technique to reduce subconjunctival hemorrhage during sub-Tenon's anesthesia. The only additional instrument required is a handheld cautery. After the eye is anesthetized with topical anesthesia such as benoxinate, the patient is instructed to look upward and temporally; the area to be incised is identified (Figure 1). The cautery is gently applied to the conjunctiva radially for about 10.0 mm. At this cauterized area, the conjunctiva is lifted and incised with a pair of Westcott scissors. The sub-Tenon, which is avascular, is identified and also incised. Westcott scissors are introduced between the globe and the sub-Tenon to create a space. Into this space, a combined solution of lignocaine 1% and bupivacaine 0.5% (Marcaine) of approximately 3 mL is injected.
We have used this technique in 80 patients during cataract surgery; no subconjunctival hemorrhage was reported. The conjunctival wound appears well healed at the 2-week postoperative review. We propose this simple technique of light conjunctival cautery as part of the sub-Tenon's anesthesia to reduce subconjunctival hemorrhage.
Ronald S.H. Chung BSc(Hons), MBBS
Chung Nen Chua MRCP, FRCOphth
1. Crandall AS. Anesthesia modalities for cataract surgery. Curr Opin Ophthalmol 2001; 12:9-11
2. Guise PA. Sub-Tenon anesthesia: a prospective study of 6,000 blocks. Anesthesiology 2003; 98:964-968