Unstable ocular dominance and reading ability.

An ocular anomaly, unstable ocular dominance, has been shown to be associated with poor reading performance in clinically selected subjects. A study is reported in which this anomaly was examined in a nonclinical sample. Two groups of children of similar reading performance and IQ but differing in chronological age were selected. The older children had a mean discrepancy between their reading and chronological age of 19 months. Unstable ocular dominance was more frequent in these poor readers. The hypothesis that this instability would lead to more errors and longer decision times for distinguishing left-right mirror-image figures was not supported. If unstable ocular dominance is to be established as anything other than a correlate of specific reading retardation, it is necessary to establish the processes through which it is operative. These have yet to be determined.