ORIGINAL ARTICLE Implantation of a Miniature Glaucoma Device Under a Scleral Flap Elie Dahan, MD, MMed Ophth and Trevor R. Carmichael, MD, PhD Purpose: To test the safety and efficacy of the Ex-PRESS TM min- iature glaucoma device when it is implanted under a scleral flap in- stead of under the conjunctiva as it was originally suggested. Patients and Methods: Between November 2000 and February 2003, the Ex-PRESS TM implant was inserted in 24 eyes of 23 patients with severe open angle glaucoma. Sixteen eyes of the 24 (66%) had had previous failed filtering surgery. The remaining 8 eyes (33%) were high risk for failures cases. A 5 3 5 mm limbal-based, 50% depth, scleral flap was raised into clear cornea. The Ex-PRESS TM implant was inserted into the anterior chamber under the scleral flap at the limbus. The scleral flap was securely sutured back, as is done in trabeculectomy operations. Results: The intraocular pressure was significantly reduced from 27.2 6 7.1 mm Hg pre-operatively to 14.5 6 5.0 mm Hg at 12 months (n = 21) and 14.2 6 4.2 mm Hg at 24 months (n = 8). Postoperatively, only two patients needed anti-glaucoma medications to keep the IOP below 21 mm Hg. Conclusions: The Ex-PRESS TM device was found to be safe and effective with few complications when it is implanted under a scleral flap even in the high-risk patients studied. Key Words: glaucoma drain, open angle glaucoma, scleral flap (J Glaucoma 2005;14:98–102) T he Ex-PRESS TM glaucoma implant is a miniature stainless steel device that was designed with the intention of offering a fast and simple glaucoma operation. The manu- facturers (Optonol Ltd, Neve Ilan, Israel) originally suggested that the implant be inserted at the limbus directly under a conjunctival flap either alone or in combination with cataract surgery. 1 This technique is relatively simple and can be performed in less than 5 minutes either on its own or in combination with cataract operations. 1 Due to the sustained hypotony observed with the original technique, placing the ExPRESS TM directly under the conjunctiva has been largely abandoned. The structure and design of the device have been reported in detail elsewhere. 2 The device is biocompatible 2 and has been reported to be reasonably safe and effective, at least initially, in a series of 98 glaucoma patients 1 or in combination with phacoemulsi- fication surgery. 3 Nevertheless, in some of our earlier cases, we found that it was difficult to prevent overfiltration while using the recommended technique. This was linked to the fact that in complicated cases the conjunctiva may offer little resistance to the aqueous that flows out of the device during the early postoperative period. In an attempt to eliminate the problems we had experi- enced, we investigated an alternative implantation technique— implanting the device under a scleral flap. The rationale, as with a guarded filtration procedure, was that the scleral flap would offer resistance to aqueous flow in the early postoperative stages as well as protecting against late conjunctival erosion. The additional surgery was routine and we hoped that the potential advantages would offset the pro- longed operating time that might appear to detract from the original concept of the implant. MATERIALS AND METHODS A non-randomized prospective pilot study was de- signed to test the safety and efficacy of the modification to the implantation technique of the Ex-PRESS TM implant device. Patients eligible for the study were older than 18 years presenting with primary open angle glaucoma, pseudoexfolia- tion syndrome glaucoma, and pigment dispersion glaucoma with failure of medical and surgical treatment (previous failed filtering surgery). Previous filtering or cataract surgery had to have taken place longer than 3 months before admission to the study. Surgery was performed at 2 centers in Johannesburg: the Oxford Eye Center and the Johannesburg Hospital. Patients were excluded if they had angle closure glau- coma, normal tension glaucoma, secondary glaucoma, neo- vascular glaucoma, uveitis, or cataract. They were excluded if they had previous ocular surgery other than filtering surgery or uncomplicated cataract surgery. The study protocol was approved by the Ethics Commit- tee of the University of the Witwatersrand, Johannesburg and was done with the permission of the manufacturer. All the pa- tients gave written informed consent before surgery. The recommended technique based on the experience in these high-risk patients is presented in detail. Received for publication May 21, 2004; accepted August 24, 2004. From the Department of Ophthalmology, University of the Witwatersrand, Johannesburg, South Africa. The authors state that they have no proprietary or financial interests in the products mentioned in this article. Reprints: Elie Dahan, P.O. Box 466, Parklands Johannesburg 2121, South Africa (e-mail: dahaneli@mweb.co.za). Copyright Ó 2005 by Lippincott Williams & Wilkins 98 J Glaucoma  Volume 14, Number 2, April 2005