What do glaucomatous visual fields really look like in fine-grid computerized profile perimetry?

ABSTRACT

Analysis of the visual fields of 20 glaucoma patients by Octopus automatic perimeter, using 229 F2 programs consisting of 30 degrees long profiles with 1 degree resolution and double measurements of the light sensitivity threshold, revealed that (1) there is a positive correlation between mean loss and mean short-term fluctuations; (2) short-term fluctuations tend to be larger with increasing loss of sensitivity; (3) however, small short-term fluctuations were also seen in areas of greatly reduced sensitivity; (4) analysis of the F2 programs showed 12 different abnormal patterns; (5) the most frequently found, 'increased scatter with normal sensitivity', appears to be the earliest perimetric sign of glaucoma, and (6) progression of the glaucomatous damage produces a 'grey area of increased scatter', usually accompanied by reduced sensitivity with a poorly defined lower and upper threshold. It is shown that a relative scotoma does not consist of a sharply bordered area with definite loss of sensitivity, but instead of a region of increased scatter with poorly definable borders. It is indicated that these sensitivity disturbances cannot be detected without extensive threshold perimetry. These findings can, furthermore, explain why quite large differences occur from one visual field examination to the next without the involvement of actual pathological changes. For combined display of several F2 programs a new mode of graphical representation is introduced.