Purpose: To compare microperimetry using the scanning laser ophthalmoscope (SLO, Rodenstock, Germany) and the recently introduced Micro Perimeter 1 (Nidek Technologies, Italy).
Design: Prospective comparative observational study.
Methods: Fundus perimetry with static threshold perimetry was performed using the SLO and the MP1 in 68 eyes of 40 consecutive patients with different retinal diseases for example, central serous chorioretinopathy, macular dystrophy, and age-related macular degeneration. With both instruments, an automated 4-2-1 staircase strategy with Goldmann III stimuli and a comparable number of stimuli were applied. The depth and size of the detected scotomata as well as the location and stability of fixation were compared between both instruments.
Results: There was good concordance of results, with 75% (51 of 68 eyes) showing an equal defect. Whereas the MP1 showed larger defects (depth and size) in 23.5% (16/68) of eyes studied than the SLO, the defects appeared larger with the SLO in 1 eye. Concerning fixation analysis, similar results were found for fixation stability with stable fixation in 47.1% (MP1: 32/68) and 48.5% (SLO: 33/68) and likewise for the location of fixation with foveal fixation in 54.4% (37/68) with the MP1 and the SLO. Whereas the average number of stimuli was similar for both instruments (MP1 56.8 +/-16.1, SLO 62.9 +/- 17.0), examination time was prolonged with the MP1 (MP1: 11m 35s +/- 3m 47s, SLO: 10m 29s +/- 3m 23s). Throughout all examinations, fundus visualization with the SLO was superior to the MP1.
Conclusions: For automated threshold microperimetry the MP1 provides results comparable to our SLO perimetry. Both instruments enable detection of sensitivity loss of the central visual field and an analysis of fixation behavior during microperimetry. Nevertheless, the MP1, with its automated real-time image alignment, facilitates examination. Additionally, the enlarged field allows testing in an area of 44 x 36 degrees instead of the 33 x 21 degree-area of the SLO. However, in comparison to our SLO-software, the current software of the MP1 requires improvements before exact measurements of defined retinal diseases are possible.