Fig. 2.

Density plots of interbatch and intrabatch signal intensity variance. The red lines show the difference in signal intensity from the arrays between specimens 1 and 2 (batch 1); the green lines show the difference in signal intensity from the arrays between specimens 3 and 4 (batch 2), and the black lines show the difference in signal intensity between the batches. The plots were normalized such that the area under each curve is 1. The Y-axis shows normalized density or frequency for each signal variance bin. Bin size ranged from 0.0127 to 0.0169. The peak of each curve indicates modal signal variance, which is similar for each of the three comparisons in each sample region. The peak values show minor differences in signal intensity variance between arrays or between batches, indicating no need to adjust for signal intensity levels between batches. Peak values ranged between: a macular arrays, 0.042 and 0.046; b surround arrays, 0.030 and 0.044; c nasal arrays, 0.032 and 0.047