Fundus perimetry with the micro perimeter 1 in normal individuals -: Comparison with conventional threshold perimetry

Purpose: To determine differential light threshold values obtained with the Micro Perimeter 1 (MP1) in healthy volunteers and to correlate them with conventional automated static threshold perimetry using the Octopus 101 Perimeter. Design: Prospective comparative observational study. Participants: Thirty healthy volunteers. Methods: In 30 eyes of 30 healthy volunteers, static threshold perimetry was performed with the MP1 Micro Perimeter (Nidek Inc., Italy) and the Octopus 101 (Haag-Streit AG, Switzerland) in the same eye in random order. Main Outcome Measures: Differential light threshold values obtained with the MP1 and their difference to differential light threshold values with the Octopus. Differential light sensitivity was compared for 21 matching points in a rectangular test grid using similar examination settings with Goldmann III stimuli, stimulus presentation time of 100 msec, and white background illumination (1.27 cd/M-2). Results: For the 21 matching locations, mean differential light thresholds with the MP1 and the Octopus were 15.5 +/- 0.8 decibels (dB) (range, 13.0-17.1) and 30.2 +/- 1.2 dB (range, 27.7-32.0), respectively. On the average, the Octopus showed higher threshold values for all test locations than the MP1. The mean difference between both examinations was 14.6 +/- 1.8 dB for all locations and 14.8 +/- 1.7 dB excluding the test locations at the blind spot. With a considerably high grade of variation according to the test point location, the difference between the 2 devices varied from 11.4 to 18.3 dB, showing a vertical asymmetry with a larger difference in the lower part of the visual field. Linear regression of the perimetric results for each test point location, excluding the area of the blind spot and the lower line of the test grid, showed significant correlation (r = 0.56; P = 0.036). Conclusions: The results show that the MP1 provides reproducible threshold values with a systematic difference compared with standard Octopus perimetry of approximately 15 dB. With a larger difference in the lower part of the visual field, differential light sensitivity values in microperimetry with the MP1 are comparable to the threshold values obtained with the Octopus 101 using a correction factor of 11.4 to 18.3 dB according to stimulus location. (c) 2005 by the American Academy of Ophthalmology.