Fluctuations of light absorption of healthy papillae repeatedly photographed over a long period of time.

In order to distinguish normal, age-related changes of the papilla from changes due to glaucoma, we investigated 7 normal papillae that had been photographed several times over a period of 11 years. By means of digital-image processing techniques, the red- and green-filtered, digitized pictures were compared directly using a subtraction method. The results seem to indicate that normal papillae do not blanch over a long period of time. The difficulties of comparison are discussed.