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Bengtsson et al. present data from the EMGTS study investigating the relationship between the presence of optic disc hemorrhages and glaucoma progression and the effect IOP reduction on these variables. The investigators have rigorously investigated the effects of confounding factors such as BP and ammetropia that would complicate such a study. It would be helpful to have included more details on the methods used. For example, a description of the criteria used to define glaucoma related RNFL/Optic disc hemorrhages. Though not stated explicitly, it is assumed that the analysis was based on monoscopic rather than stereoscopic images: it is possible that this might result in an underestimate of any changes in the shape of the neuroretinal rim.
The principal findings are that optic disc hemorrhages are associated with a reduced time to progression � this far the study accords with clinician perceptions and previous studies. More contentious is the observation that the reduction in IOP does not appear to affect the frequency of disc hemorrhages. A more conservative conclusion would be that that a greater degree of IOP reduction might be required to reduce the risk of disc haemorrhages; this would be consistent with the observation that the rate of progression is inversely related to the degree of IOP reduction.
The discussion section addresses the issue that the presence of disc hemorrhages in treated glaucoma patients is often used to set targets for further IOP reduction. The conclusions are reasonable with respect to the IOP reductions seen EMGTS, but cannot, on the data presented be extrapolated to clinical practice in which greater reductions in IOP may be anticipated, for example following filtration surgery.
The study adds significantly to the debate concerning optic disc changes in glaucoma and their relationship to nerve fiber layer hemorrhages. However, further work is required � in patients with a great range of IOP reduction to clarify the effect of glaucoma treatment on subsequent disc hemorrhage rates.