A common lens nuclear area in Scheimpflug photographs

Scheimpflug photography has been proven to be a useful method for documentation of opacification of the lens nucleus. In the present study, a common lens nuclear area (CNA) is established for photometry of nuclear cataract on Scheimpflug photographs. Using the established method, one measurement for one photograph, and one photograph for each subject is enough for the photometry of nuclear density. Further, this method allows detection of a 10% change in nuclear density between two occasions with a group of at least 7 subjects, and for independent groups with at least 95 subjects in each group (alpha = 0.05, beta = 0.10). It is anticipated that the CNA will provide a useful tool for quantitative determination of nuclear cataract.