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L. W. Herndon, Jr., L. Marzette; A Comparison of the Ex-press Device With Standard Trabeculectomy. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4186. doi: https://doi.org/.
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The Ex-press device (Optonol Ltd) is a non-valved glaucoma shunt designed to lower intraocular pressure (IOP). This study was a comparison of the success and complication rates of glaucoma patients who had Ex-press device implantation versus those who had conventional trabeculectomy.
The study was retrospective in design and compared the records of 76 subjects who had Ex-press implants to 77 who had conventional trabeculectomies. All surgeries were performed by one of the authors (LWH). Some of these procedures were combined with phacoemulsification when a visually-significant cataract was present.Postoperativly, patients were scheduled for follow up visits on day one, week one, month one, and three to six months. At each of these visits, data such as IOP and visual acuity were recorded. The presence of postoperative complications was also assessed.Success was defined as an IOP of 6 to 21 in patients who did not require further glaucoma surgery in the eye of note. The maximum follow up period was 15 months. In attempt to stratify patients who had successful outcomes, four levels of success were created: (A) IOP <=21; (B) IOP <=18; (C) IOP <=15; (D) IOP <=12. Secondary outcomes included evaluating the number of preoperative to postoperative glaucoma medications required.
The study showed similar success rates for Ex-press and trabeculectomy groups 79% to 67%. The data do indicate that the Ex-press group did have a greater reduction in preoperative to postoperative medications compared to the trabeculectomy group (90% vs. 81%; p-value 0.019).Postoperatively, the Ex-press group did have an overall greater reduction in IOP (from the preoperative period to the most recent visit) when compared to the control group: 50.9 vs. 44.6 %. However, this value did not reach statistical significance with a p-value of 0.356. Eight (12%) Ex-press subjects failed because of hypotony compared to 14 (21%) trabeculectomy controls.
The present study demonstrates that Ex-press device implantation has similar efficacy to trabeculectomy in lowering the IOP of glaucoma patients. Patients with Ex-press devices also had a greater reduction in the number medications required from the preoperative to the postoperative period.Furthermore, the data suggest that the Ex-press device results in an overall greater percentage reduction in IOP than with trabeculectomy, though this did not reach statistical significance.The Ex-press device is a viable alternative to the conventional trabeculectomy.
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