Fig. 2. It is impossible to determine whether a disc is damaged when it is in the early stages of damage. A. A disc with a rim/disc ratio of 0.4 in a patient who has actually gotten worsen. This can be seen by examining illustration B, which is a prior photograph of the optic nerve with a rim/disc ratio of 0.3. This, however, also represents actual deterioration from a previous state, as shown in C, which depicts the optic nerve in its healthier condition. (Spaeth GL (ed). Glaucoma. In Tasman W, Jaeger EA (eds). The Wills Eye Atlas of Clinical Ophthalmology. Philadelphia: Lippincott-Raven, 1996.)