Two adaptive perimetric strategies for the search and the analysis of scotomata have been developed and tested over the normal and pathologically disturbed blind spot area. Adaptive procedures automatically concentrate their search effort upon areas of pathological disturbance and avoid time loss used for declaring normal areas as such. Provided a first scan of low spatial resolution, detects only one edge of the blind spot, spatial resolution increases and analyses the blind spot, returning to low resolution as soon as the border of the blind spot is crossed and normal sensitivity is again attained. Two adaptive strategies are described. One reduces examination duration to 1/2, the other to about I/3 when compared to a similar non adaptive high resolution strategy. Only in the latter this time reduction has to be paid by some loss of information. The accuracy of the threshold determination method described is limited whereas spatial precision is high. Hence a more accurate threshold determination technique has to be added if the postulate of great threshold accuracy is to be fulfilled.

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Flexible computer programs have been developed which are capable of distinguishing between normal and defective areas in the visual field, in that the computer logic only grossly probes normal areas and concentrates on the abnormal areas. As soon as a defect is discovered, it is analyzed with greater accuracy. In this way, no time is wasted analyzing and confirming normal conditions. At the same time, the system is highly effective in respect of pathologically defective areas of the visual field. The principle is described and illustrated with some clinical examples (paracentral scotomata).

The automatic Octopus perimeter has a large software development potential. An important property of the Octopus programs developed to date is their ability to distinguish between pathological and normal behaviour. At the moment, program development is concentrating upon programs in which criteria of normality are used as feed-back parameters during the examination itself, and thus guide the visual field analysis. This property permits the algorithm to undertake a precise spatial analysis of disturbed visual field areas, without wasting time on a detailed analysis of normal areas. The efficiency of a visual field examination program is thereby substantially increased (SAPRO* program). Using the F-program series, individual (as opposed to fixed) stimuli configurations can be realised, which may represent a better fit to a particular problem. The principles of two other programs, SARGON and DELTA, have been described before (Fankhauser and Jenni 1981).