Small incision trabeculectomy avoiding Tenon's capsule. A new procedure for glaucoma surgery.

BACKGROUND AND PURPOSE

Wound healing at the level of Tenon's capsule is a common cause of trabeculectomy failure. The purpose of this study is to present a new technique for glaucoma filtering surgery in which an injury to Tenon's capsule is minimized.

METHODS

A 2.5-mm conjunctival peritomy was performed without cutting Tenon's capsule. A partial-thickness incision was made at the limbus and a scleral pocket was dissected 2 to 3 mm posteriorly. The subconjunctival space was entered with a cystotome passed through the scleral pocket, and balanced salt solution (BSS, Alcon Laboratories, Ft. Worth, TX) was injected, forming a subconjunctival bleb. In patients considered high risk, 5-fluorouracil (5 mg) was mixed with the BSS injected. The anterior chamber was entered at the initial limbal incision. A 1.5- by 1-mm fragment of the floor of the pocket was excised, followed by a peripheral iridectomy. The scleral wound, as well as the conjunctiva, was closed with separate 10-0 nylon sutures. This procedure was performed in 30 glaucomatous eyes. Seven high-risk eyes received four to seven postoperative injections of 5 mg of 5-fluorouracil.

RESULTS

Preoperative intraocular pressure (IOP) was 34.5 +/- 8.1 mmHg. Postoperative IOP was 13.2 +/- 4.1 at 6 months (P < 0.01), and 90% of the eyes had IOP less than or equal to 18 mmHg without medication. Mean follow-up was 7.6 months (range, 6-14 months). Blebs were low-lying and diffuse. No serious complications were encountered.

CONCLUSIONS

This new technique is a safe procedure that effectively reduces IOP. It is done through a small incision without sophisticated instruments. More cases and a prospective trial are needed to ascertain its potential advantages over those of conventional trabeculectomy.