Experimental Design and Batch Structure: This data set consists arrays processed in 13 groups over a five month period (July 2006 to Dec 2006). Most groups consisted of 12 samples. All arrays in this data set were processed using a single protocol by a single operator, Feng Yiao. Processing was supervised directly by Dr. Lu Lu. All samples were scanned on a single Illumina Beadstation housed in the Hamilton Eye Institute between July 28 and Dec 21, 2006. Details on sample assignment to slides and batches is provide in the table below.