Static fundus perimetry using the scanning laser ophthalmoscope with an automated threshold strategy

The purpose of this study was to develop software that allows the performance of routine static threshold perimetry using the scanning laser ophthalmoscope (SLO) and the comparison of the results with conventional computerized cupola perimetry. The original software does not allow performance of static threshold perimetry within a reasonable examination time.

Static perimetry was performed in random order on 50 healthy eyes using our SLO staircase threshold perimetry technique and the Octopus 500 (program 38). We compared the relative sensitivities for each of 25 corresponding visual field locations.

Mean sensitivity in the SLO perimetry amounted to 32.7 dB (range 25-37 dB) while it was 28.7 dB in the Octopus. For all test locations the SLO showed higher dB values on average. The mean difference between both methods was 3.7 +/- 0.8 dB (range 1.4-5.8 dB) when the test locations at the blind spot were excluded (linear regression between the two methods: r = 0.843, P < 0.0001). The mean time interval between two stimulus presentations was 2.5 s with the SLO perimetry.

With the Heidelberg software, automated static threshold perimetry using the SLO is possible within reasonably short examination times. The mean time interval between two test point presentations is about one tenth of that necessary using the original Rodenstock software. There is a systematic difference between SLO and Octopus fields of about 4 dB which was not very much influenced by the stimulus locations.