Normal values for fundus perimetry with the microperimeter MP1

Abstract

Purpose: To identify age-stratified normal light sensitivity values for microperimetry (fundus perimetry) and to evaluate the short-term repeatability of the MP1 microperimeter in normal volunteers.

Design: Multicenter, prospective, observational study.

Participants: One hundred ninety subjects.

Methods: One hundred ninety eyes of 190 healthy volunteers (age range, 20-75 years) underwent automatic, full-threshold microperimetry of the central field (20 x 20 degrees, 77 stimulated points) with the MP1 microperimeter (Nidek Technologies, Gamagori, Japan). Fixation was documented simultaneously. A subgroup of 10 subjects was retested after 1 hour and 1 week to determine the repeatability of this technique.

Main outcome measures: By linear regression analyses, light sensitivity values were obtained from 4 fundus areas and were analyzed for differences related to region, age, and, in a subset of subjects, repeat testing over time and right and left eye variability. Short-term repeatability for each area was evaluated by calculating intraclass correlation coefficients.

Results: Linear regression analysis showed a significantly greater (P<0.0001) mean macular sensitivity of 19.6+/-0.5 dB in the 20 to 29 years of age group compared with 18.6+/-1.5 dB in the oldest age group of 70 to 75 years. These results were confirmed by the fifth percentile of light sensitivity threshold distribution. Normal and 95% confidence interval age-stratified values were calculated. When results for all 190 subjects were analyzed by region, the superior retinal sector showed significantly lower mean sensitivity values than other sectors (P<0.01, Bonferroni test). In a subset of 10 subjects, repeatability of the test performed at 3 separate visits showed consistent values over time in all areas (P<0.01, intraclass correlation coefficients).

Conclusions: Automatic fundus perimetry with the MP1 microperimeter allows for an accurate, repeatable, topographically specific examination of the retinal threshold in selected retinal areas. These findings are the first extensive database of age-related, normal MP1 microperimetry results available to clinicians.