Chung and colleagues [18] retrospectively analysed the effect of macular ischaemia on the outcome of treatment of DME with Avastin [TM]. They collected data on 59 eyes of 53 consecutive patients and analysed their preoperative imaging tests (fluorescein angiograms) for signs of ischaemia. They then divided the patients into two groups, those with and without signs of ischaemia, in order to assess their outcomes. 3 months after treatment, the group with ischaemia showed a reduction in visual acuity from approximately 20/63 to 20/80, whereas the group without ischaemia showed an improvement in visual acuity from 20/100 to 20/80. Nine of 18 eyes (50%) in the ischaemic group, but only 9 of 41 eyes (21%) in the non-ischaemic group, experienced visual losses of >or=1 line on the ETDRS chart (P = 0.031, Pearson chi-square test). Four eyes (22%) in the ischaemic group, but only 2 eyes (5%) in the non-ischaemic group, lost >or=3 lines (P = 0.042, Pearson chi-square test). Whilst these data show a poorer outcome for patients with macular ischaemia treated with Avastin [TM], compared to those without, they do not show how treatment with Avastin [TM] compares to what would have happened to these patients' vision without any treatment at all. As already discussed the natural history of ischaemic DME is of a decline in visual acuity and there is currently no established treatment option. The investigators would not expect the patients with ischaemic DME to do as well as those without ischaemia as they tend to have much more severe disease than those without ischaemia. In this particular group it appears that the baseline acuity was much poorer in the non-ischaemic group, which gave them more scope for improvement in visual acuity with treatment than the non-ischaemic group which had, on average, better visual acuity, and probably much less oedema, to begin with.