[Different significance in normal subjects and in glaucoma patients tested with Optopol PTS-910, in the galucoma...

to quantify the inter-test variability (dB) for the Optopol PTS automated perimeter, Glaucoma Fast threshold program.

A prospective study was performed on 166 glaucomatous patients and a control group of 30 normal subjects, tested by complete ophthalmological exam and automated perimetry (Optopol PTS-910). The visual field was tested weekly for 4 consecutive weeks. The visual field defects were classified according to the Aulhorn-Karmeyer descriptive scale.

For the control group, the medium inter-test variability was of 1.57 +/- 0.24 dB, lower next to fixation and increasing towards the 50 degree isopter. The medium inter-test variability increases along with the perimetric stage :1.57 +/- 0.66 dB for pre-perimetric glaucoma, 2.13 + 1.04 dB for non-specific defects group, 3.23 + 1.01 dB for the stage 1, 3.52 + 2.61 dB, for the stage 2, 3.65 + 1.19dB for the stage 3 and 5.82 +/- 1.67dB for the stage 4. For the cases of preperimetric glaucoma and non-specific defects, a similar profile of variability to the normal subjects can be observed. For the stages 2-4, the profile of the areas with maxim inter-test variability moves towards the relative scotoma and the surrounding area.

A better description of the inter-test variability and the evolution of this intricate parameter of the retinal light sensitivity is useful for the differential diagnostic between the real change and the "background noise" in early detection of the functional progression in glaucoma.