A new diffuse loss index for estimating general glaucomatous visual field depression.

Experience with a number of visual fields has shown that the algorithm used earlier for estimating general depression in glaucomatous visual fields was too conservative. A new, more sophisticated algorithm for calculating diffuse loss has been devised and the results obtained in the evaluation of 20 glaucomatous visual fields were compared with those obtained manually. The new algorithm is less restrictive, yet produces values for diffuse loss which agree well with the empirical estimates (R = 0.97, N = 14). The new diffuse loss index is also compared with the mean defect index (R = 0.77, N = 159), the 18th Bebie curve ranked value (R = 0.87, N = 159), and the previous diffuse loss index (R = 0.98, N = 105). A general discussion of various aspects of diffuse loss is included.