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Editors Selection IGR 12-2
Surgical Treatment: Drainage devices 2
Comment by Malik Kahook on:
55391 Prospective Randomized Study Comparing Ex-PRESS to Trabeculectomy: 1-Year Results, Wagschal LD; Trope GE; Jinapriya D et al., Journal of Glaucoma, 2015; 24: 624-629
The ExPRESS Glaucoma Filtration Devices (Alcon, Fort Worth TX) has been available for use across the globe for over a decade. Multiple studies have been published, both retrospective and prospective, comparing the device's efficacy compared to standard guarded filtration surgery. More recently, Wagschal and colleagues published this report in which they compared the efficacy and safety of the Ex-PRESS device compared to standard trabeculectomy. This prospective randomized trial defined complete success as an intraocular pressure (IOP) between five and 18 mmHg and a 20% reduction from baseline without use of IOP lowering medications. A total of 64 subjects were enrolled (33 Ex-PRESS and 31 trabeculectomy). The study results showed that IOP was similar between groups at baseline and last follow up with complete success reached in 57% of trabeculectomy patients versus 70% in Ex-PRESS patients (P = 0.28). Other endpoints including surgical time, number of glaucoma medications, visual acuity (VA), central corneal thickness and endothelial cell counts were also reported to be similar.
One often noted benefit to using the Ex-PRESS is a perception of lower complications compared to standard trabeculectomy. A closer look at the data presented reveals an unusually high number of early transient hypotony in both groups (39% in both groups) raising questions regarding the technique for suturing the scleral flap at the time of surgery. This is not discussed further in their report. Sixteen percent in the trabeculectomy group versus none in the Ex-PRESS group had a hyphema (P = 0.02) which is noteworthy since a decrease in tissue manipulation is an often noted benefit to using the device. Also, a closer look at VA reveals that vision in the Ex-PRESS group returned to baseline by one month, whereas the VA in the trabeculectomy group remained significantly depressed at last follow-up. Also 30% in the trabeculectomy group, compared to only 3% in the Ex-PRESS group, experienced a loss of over two Snellen lines on VA testing. It appears from the authors' own data that use of the Ex-PRESS device does lead to enhanced speed of VA recovery and a decrease in loss of VA from baseline compared to standard trabeculectomy. This makes the conclusion that there was no difference in VA between groups, due to a focus on results between groups rather than comparing to baseline, a bit perplexing.
Monocular patients in particular would benefit a great deal from quicker visual recovery and a return to baseline VA postoperatively
Monocular patients in particular would benefit a great deal from quicker visual recovery and a return to baseline VA postoperatively. The final conclusion by the authors states 'these results suggest clinical equivalency between Ex-PRESS and trabeculectomy but at an increased cost.' This final conclusion is not supported by the authors' own data and downplays the benefit of quicker visual recovery, return of VA to baseline and a significant reduction in some complications.
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