[Ahmed versus Baerveldt shunts: which one is better?].

rainage devices are an efficient surgical treatment for esistant glaucoma or when previous filtrating surgery fails. here are 2 types of these devices: those comprising valves, n which the device includes a restriction at the outlet of he aqueous, and devices without valves in which the tube onnects with a dish without any type of restriction. Of the ormer, the best known is the Ahmed implant, while the est-known valveless device is the Molteno or the Baerveldt. any studies have compared these devices to analyze their idor long-term efficiency as well as their complications.1,2 any of said publications comprise retrospective studies ased on the personal experience of a surgeon, which means hat sometimes the number of cases is small. In 2008, the merican Ophthalmology Academy published an article n Ophthalmology analyzing all previous papers on these rainage devices and concluded that at this point in time here are no comparative studies having sufficient quality o affirm that one drainage device is more effective than nother, with the exception of the data that confirm that he dish surface plays an important role in reducing intraoclar pressure (IOP).3 Shortly before said article, 2 phase II perspective and randomized clinical trials had begun o compare the Ahmed device with the Baerveldt device. ne of said trials is the Ahmed Baerveldt Comparison Study ABC) (http://www.clinicaltrials.gov/ct2/show/NCT00376363) nd the other is the Ahmed Versus Baerveldt Study (AVB) http://www.clinicaltrials.gov/ct2/show/NCT00940823). The