The ultimate goal is the development of visual tests that can be used by practicing eye care specialists to evaluate the "useful" vision in patients with bilateral central scotoma. Patients with central scotomata, as a general rule, have adequate vision for mobility under ideal conditions. The factors that limit their residual vision include contrast and illumination levels. The specific aims of this investigation are (1) to determine whether the reductions in contrast sensitivity correlate with the severity of visual problems that patients experience in everyday situations; (2) to determine whether contrast sensitivity correlates better with the patients' experience than other visual measures, such as the size of the patients' scotoma; and (3) to determine whether the measurement of vision at different illumination levels contributes to the evaluation of the patients' ability to function in their environment. The approach for evaluating the relative merits of different visual tests and illumination levels uses a multiple regression analysis. The patients' ability to function in "everyday" situations will be assessed by asking the patients to estimate (on a scale of 1 to 10) the degree of visual difficulty that they experience. A multiple regression (R2) value will be computed between the visual measures, such as contrast sensitivity, and the questionnaire responses.