COMPARING SUPRATHRESHHOLD AND THRESHHOLD SPLITTING PERIMETRY USING THE TUBINGER AUTOMATIC PERIMETER CC

Background: We compared the standard suprathreshhold strategy to the s o-called threshhold splitting strategy with 5 and 2 dB steps. The aim of the study was to establish whether the threshhold splitting strateg y had advantages over the suprathreshhold strategy that has been used to date. Method: We examined the 30 degrees visual field in 49 volunte ers using suprathreshhold perimetry and on the same day threshhold spl itting perimetry on the Tubinger Automatic Perimeter CC. A total of 19 1 test points were examined in suprathreshhold strategy. Using the thr eshhold splitting strategy, 67 test points were examined, with a test- point design similar to other perimeters with the threshhold splitting strategy. The criteria for inclusion in the study were central tight sensitivity differences greater than 25 dB, fixation better than 80 % and an illumination class density < 2. Results/Discussion: The average duration of the examination using the suprathreshhold strategy was 2- 3 min quicker than the threshhold splitting strategy in normal visual fields or small scotomas, but it took up to 15 min longer if large sco tomas were present. Interpretation of the scotoma configuration showed subjective differences: the smaller the scotoma, the greater the diff erences because of the fact that threshhold splitting perimetry utiliz es test points that are farther apart than those used in suprathreshho ld perimetry.