[Study of early glaucomatous visual field defects with the automatic perimeter Topcon SBP-1000. Comparative study...

The automatic perimeter TOPCON SBP-1000 uses light emitting diodes (LED's) for stimulus generation and thus completely differs from the projection type perimeter OCTOPUS 201. In order to get some first idea about the capabilities of the TOPCON SBP-1000 22 eyes of 18 patients with early glaucomatous visual field defects were examined both with the glaucoma program/TOPCON SBP-1000 and program 31/OCTOPUS 201. Field defects were divided into three groups according to the total loss (program DELTA/OCTOPUS 201): group I with a total loss of 0 dB, group II with a total loss of 1-200 dB, group III with a total loss greater than 200 dB. Evaluation and comparison of visual field results is done after discussing the most important technical parameters and fundamental aspects of methods and strategies using the total percentage of "normal" test points, "small relative defects", "deep relative defects" and "absolute defects". We could show that specificity and sensitivity for the detection of earliest field defects are quite equal both in the TOPCON SBP-1000 and in the OCTOPUS 201. Concerning the detection of more pronounced visual field defects the TOPCON-perimeter has a somewhat smaller sensitivity as a result of the different definition of the category "normal"; at the same time there is a tendency for showing up more "absolute defects" instead of "deep relative defects". Technical parameters and strategies are discussed critically taking into consideration the practical experience obtained during this first routine testing.