Uncontrolled variables often limit meaningful assessment of visual sensitivity. Previously, we developed a procedure and apparatus for in vivo assessment of light absorption by the human lens. In the current study, we modified a widely used automated perimeter to include our procedure for obtaining an index of lens density. Nineteen individuals were tested on both the original apparatus and the modified perimeter. Results were comparable with a correlation of r = 0.92 (P less than 0.01). We conclude that employing the procedure on an automated perimeter is a practical method for obtaining an accurate lens density index.