In a population of 188 nondiabetic patients with early cataracts or nuclear brunescence, we assessed the degree to which contrast sensitivity function (CSF) provided more information about a patient's visual disability than high contrast visual acuity measurements. Data collected included LOCS II cataract classification, Bailey-Lovie visual acuity (LogMAR score), Lotmar interferometric visual acuity (LI VA), and distance contrast sensitivity function (CSF) using the Vistech 6500. Generalized least squares regression models in which CS was the dependent variable and either LogMAR score or LI VA was among the independent variables were used to ascertain whether CSF provided additional information about visual disability to that provided by LogMAR score or LI VA. Contrast sensitivity function was decreased only by nuclear opalescence at high frequencies (12 to 18 cpd); for all other cataract types and nuclear color, CSF testing provided no more information about cataract-related visual loss than LI VA or LogMAR score. Measurement of CSF using the Vistech 6500 system in patients with early cataracts provides information on visual dysfunction beyond that provided by LogMAR score or LI VA only in patients with nuclear opalescence, and that may not be clinically significant.