Fixation characteristics of patients with macular degeneration recorded with the MP-1 microperimeter

Purpose: The authors examined the fixation stability patterns of people with age-related macular degeneration (AMD) using the MP-1 microperimeter and describe a method to bypass some calibration artifacts that can influence the fixation results. Method: The preferred retinal locus (PRL) and fixation patterns of 37 eyes with AMD and the fovea's location relative to the middle of the optic disc of 10 experienced controls were measured. For the patients, fixation characteristics such as the former fovea's location, PRL distance, and fixation stability were analyzed. Results: For the controls, the mean foveal distance temporal to the middle of the optic disc was 15.5 deg +/- 0.86 deg horizontally and -1.33 deg +/- 0.71 deg vertically. Thirty-one out of 37 PRLs occurred in the upper and right quadrants of the retina. There were significant positive correlations between fixation stability and PRL distance from the former fovea. Time since diagnosis and acuity also showed positive correlations with fixation stability and PRL distance from the fovea. Conclusions: The authors recommend that fixation stability recorded with the MP-1 be analyzed based on the raw data. Most of the fixation parameters obtained agree with those reported in the literature, if proper calibration is used.