Comparison of mean retinal sensitivities at each time point in the three severity groups divided by perfusion density at 1 month: severe (0–17%), moderate (17–34%), or mild (34% or more). (A) Divided by time point. At all times, greater perfusion density was accompanied by higher retinal sensitivity. (B) No significant improvement was observed over time in the severe group divided by perfusion density but significant improvements were observed in the moderate and mild groups. (A,B) are rearrangements of the same data. The bars show the mean ± standard error of the mean (severe group: n = 35 at baseline, n = 36 at 6 and 12 months; moderate group: n = 42 at baseline, n = 45 at 6 and 12 months; mild group: n = 42 at baseline, n = 55 at 6 and 12 months). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, from two-way analysis of variance with Tukey’s multiple comparisons test.