[Glaucomatous visual fields: observation of development with the Octopus automatic perimeter (author's transl)].

The analytical program Delta was used to determine long-term fluctuations and accuracy of measurement of the program 31 of the Octopus when used with glaucoma patients. Program 31 examines the 30 degree field. The test locations are arranged in a square grid with 6 degree resolution. The program Delta determines and compares 1) the disturbed area in %; 2) the total loss, the total sensitivity being around 2000 dB; 3) the total loss in dB per mean number of disturbed points. 32 eyes of 22 patients with established glaucomatous field defects were examined twice within 2 to 6 days and 2 months later, twice again within this number of days. The size of the disturbed area served for classification of our sample into 3 groups: 1st group: disturbed area 1-33%; 2nd group: disturbed area 34-66%; 3rd group: disturbed area 67-100%. Long-term fluctuations and accuracy of measurement were determined as follows: 1) Disturbed area between 0.7 +/- 8% in group 3 and 1.7 +/- 13% in group 2. 2) The total loss increases proportionately to the disturbed area and was 4.9 +/- 29.2 dB in group 1 and 31.8 +/- 82.4 dB in group 3. 3) The total loss per mean number of disturbed points was 0.5 +/- 2 dB in group 1 and 0.3 +/- 1.2 dB in group 2. This means that, if the learning effect is over, changes of more than 2 dB, especially if several adjacent points are affected, are a significant loss, the learning effect, as determined in an earlier study, may go up as high as 2dB per point.