Critiquing the clinical trials

摘要

Dr Higginbotham: Di Singh, are the differences in the study designs evaluating optic nerve changes across AGIS, CIGTS, EMGT and OHTS, coloring our view of what might be the true progressive rate of glaucoma?Dr Singh: I think a clear contrast would be between OHTS and EMGT. In OHTS, if you look at the patients that progressed based on optic nerve or field criteria, about half the patients had progressed on one or the other (endpoint reached with 55% optic nerve versus 35% visual field, and 10% combined) Whereas, in EMGT over 86% progressed and reached an endpoint by visual fields alone and 1% using optic nerve criteria. The EMGT didn't use stereo fundus photos to examine the optic nerve. So, the old adage, if you have a hammer the whole world looks like a nail. The Swedes know and do perimetry. I think that did impact the EMGT study to a significant extent. I don't think it overall changed what they would have found, but it perhaps did impact what the rates of progression were.