Different fixation targets affect retinal sensitivity obtained by microperimetry in normal individuals

Abstract

Purpose

To determine the differences in the retinal sensitivities obtained by microperimetry with a single cross or a circular fixation target in normal individuals.

Methods

Thirty-two eyes of 16 healthy volunteers (mean age 28.9±1.4 years, range 24–44 years) were studied. The retinal sensitivity of the central 0 degrees and of the mean central 2 degrees consisting of 8 points were determined independently using the two different fixation targets with Microperimeter 3. The Goldmann III stimulus with a luminance of 1.0 cd/m² was presented for 200 ms on a white background.

Results

The retinal sensitivity of the central 0 degrees was significantly better with the circular target than that with the cross target (P=0.003, right eyes; P=0.001, left eyes). The mean retinal sensitivity in the central 2 degrees was not significantly different between the cross and circular fixation targets. (P=0.07, right eyes; P=0.08, left eyes).

Conclusion

These results indicate that the circular fixation target is a better target to use to evaluate the central retinal sensitivity. The difference in the retinal sensitivity is most likely due to the cross fixation target overlapping the test stimulus target.

Keywords:

• microperimetry
• retinal sensitivity
• fixation targets
• stimuli

Acknowledgments

This work was supported by JSPS KAKENHI (Grant Number JP16K11280). The authors thank Professor Duco Hamasaki of the Bascom Palmer Eye Institute of the University of Miami for his critical discussion and editing the final manuscript.

The abstract of this paper was presented at the European Association for Vision and Eye Research (EVER) 2015 Congress as a poster presentation with interim findings. The poster’s abstract was published in “Poster Abstracts” in Abstract book EVER 2015: https://www.ever.be/~/media/Files/2015/EVER-2015-abstractbook/EVER2015abstract-bookweb.pdf?la=en.

Disclosure

The authors report no financial support or financial conflicts of interest in the design and conduct of study, collection of data, management, analysis and interpretation of data, preparation, review, and approval of the manuscript, and no conflicts of interest in this work.