[Graphic analysis of topographic trends in perimetry follow-up of glaucoma]

GATT is a new, graphic method of showing the development of visual fields in glaucoma and other diseases. The grayscale maps of a series of two or four fields are superimposed with a simple logic, producing the following pattern: all stable areas are displayed in the usual way, thus giving defects a typical appearance. Changed areas appear as stripes, alternately showing the grayscale of the two fields. The orientation of the stripes is vertical in zones of improvement and horizontal in areas of deterioration. The level of contrast indicates the amount of change. The authors examined the development of the visual fields in 30 glaucomatous eyes. With the help of GATT it was established that areas of change were close to existing defects. Second, most of the changes were at the periphery. GATT is not only proving to be a method for perimetric follow-up in glaucoma cases that furnishes much useful information, but is also raising hopes of new findings concerning the course of glaucoma.