The present invention provides a reading test to measure vision loss. In one embodiment, the vision loss is due to disease progression. The tests are useful in evaluating the effects of intervention in vision deterioration. The tests are non-invasive, simple, quick, sensitive, reproducible, and easy to administer. The tests measure the subject's reading speed and accuracy under defined conditions of illumination and contrast. The results of these tests may be used to determine if treatment of a disease should be initiated, terminated, altered, or remain unchanged.
