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Editors Selection IGR 8-3
Surgery: Ex-PRESS versus TE
Comment by Tarek Shaarawy on:
16901 Comparison of trabeculectomy with Ex-PRESS miniature glaucoma device implanted under scleral flap, Maris PJ Jr; Ishida K; Netland PA, Journal of Glaucoma, 2007; 16: 14-19
In this retrospective comparative study by Maris et al. (344) 50 eyes with Ex-PRESS implant placed under a scleral flap, were compared with 50 matched control eyes treated with trabeculectomy.
Despite the trial having a non-randomized retrospective design, with its potential sources of bias, and despite the relatively short follow-up (approximately 11 months), it remains quite interesting being the first comparison, of any study design, between trabeculectomy and Ex-PRESS.
The authors report similar IOP reduction both at 6 and 15 months.
Similarly there was no significant difference in success between the two groups. Success was defined as intraocular pressure (IOP) ≥ 5 mmHg and ≤ 21 mmHg, with or without glaucoma medications, without further glaucoma surgery or removal of implant. Such a success criterion poses a certain disadvantage, as IOP is considered irrespective of having been achieved through the surgery alone or together with postoperative topical anti-glaucoma therapy. Meaning that deducing the so-called complete success (i.e., patients achieving IOPs below certain levels without postoperative medications) is impossible, as it is not reported. On the other hand, early postoperative hypotony and choroidal effusion were significantly more frequent after trabeculectomy. It is worthy of note, though, that these complications did not result in differences in the final visual outcomes, IOP reduction, or success rates between the two groups.
The authors suggest that the small lumen (50μm) of the Ex-PRESS provides additional resistance compared to the much larger Kelly punch, which provides a 750 μm opening, which might lead us to reflect on if such sizes are really an overkillThe authors suggest that the small lumen (50 μm) of the Ex-PRESS provides additional resistance compared to the much larger Kelly punch, which provides a 750 μm opening, which might lead us to reflect on if such sizes are really an overkill.
The authors report one case of late-onset endophthalmitis in the Ex-PRESS group. Although this might well be unrelated to the implant, it is not clear, as the authors suggest, whether or not patients are at increased risk of endophthalmitis.
The authors should be congratulated for this first step toward understanding the potential place of Ex-PRESS in our surgical armamentarium.
What remains to be seen is complete success rates over longer follow-up periods in a prospective manner, as well as whether potential benefits from the use of such implants (potentially less hypotony related complications, and dispensing with iridectomy) would translate into real added value to our patients.
In particular and very relevant to such a study, cost effectiveness analysis (the amount of money spent per clinical outcome) and cost-utility analysis (to objectively measure the benefit derived from an intervention for the costs expended) should be attempted.
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