Comparing the MPE to the effective irradiances, , used in this study found that the margin for safety between the and MPE ranges from a ratio of 6.2 to (last column in Table 3). The data trends in Fig. 2 indicate that the damage threshold may have a weak dependence on beam diameter much larger than the 0.35-cm limiting aperture used in the ANSI.1 For the 0.25-s exposures, the 1.9-cm beam had a statistically significant higher threshold () than the larger beam diameters, indicating that the threshold is dependent on beam diameter, at least for (Fig. 2). The 2.4-, 4.7-, and 9.5-cm beam diameters converged toward a peak radiant exposure threshold level of as indicated by their significantly overlapping 95% confidence intervals. This suggests that for 0.25-s exposures at 1070 nm, the peak radiant exposure threshold converges to , settling to a safety margin (ratio of ) of , for . The 0.1-s did not have overlapping 95% confidence intervals for peak radiant exposure thresholds of 52.2 and for the 1.1- and 4.7-cm beam diameters, respectively. If the evidence for convergence to in the 0.25-s data is considered, it is likely that the threshold for the 4.7-cm case represents a value for convergence between threshold and increasing beam diameters for 0.1-s exposures, giving a safety margin of between threshold and MPE for very large beam diameters. The 10-s exposure data, however, were 432.24, 189.4, and for the 0.6-, 1.1-, and 1.9-cm beam diameters, respectively, and exhibit no overlap in 95% confidence intervals, suggesting that convergence of the threshold with respect to beam diameter was not achieved. The larger spread in damage thresholds for the 10-s data also suggest that damage threshold is more dependent on beam diameter for very long exposures compared to exposures . The 0.01-s exposure thresholds for the 0.6- and 1.1-cm diameters have overlapping confidence intervals, but the larger 2.4-cm beam diameter had a peak-radiant exposure damage threshold 33% less than the smaller beams, suggesting some dependency on beam diameter even for this very short exposure. These trends in beam diameter dependency for MVL threshold data are suspected to be caused by different damage mechanisms for very short exposures () compared to the longer exposure durations.