Purpose: To evaluate the effect of interpupillary distance (IPD) on stereoacuity using 2 kinds of stereoacuity tests in a normal population. Methods: The distance stereoacuities of 33 healthy volunteers with no evidence of ocular diseases were measured with the Frisby Davis distance (FD2) stereotest and a 3-dimensional monitor-based distance stereotest (distance 3-D stereotest). These 2 kinds of stereotests were repeated using horizontal periscopes to increase the IPD 2- and 3-fold in order to investigate the effect of IPD increase on stereoacuity. Results: The mean age of the participants was 28.5 years (range 20-41 years). The mean logarithms of the individual minimum angle of stereodiscrimination (logMAS) were 1.04 ± 0.23 (range 0.70-1.48 logMAS) with the FD2 stereotest and 1.52 ± 0.19 (range 1.00-1.85 logMAS) with the distance 3-D stereotest. As the IPD increased 2- and 3-fold, the logMAS measured with the FD2 stereotest improved from 1.04 to 0.98 and 0.91 (P = 0.061 and P = 0.003), respectively, and those measured with the distance 3-D stereotest worsened from 1.52 to 1.73 and 1.85 (P < 0.001 and P < 0.001), respectively. Conclusions: Changes in IPD measured with the FD2 stereotest exhibited opposite effects to those measured with the distance 3-D stereotest. This reflects what is known to happen in the real world, i.e., that stereoacuity improves as IPD increases.
Bibliographical noteFunding Information:
Acknowledgments This research was supported by the Basic Science Research Program of the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology of South Korea (Grant Number 2010-0007817).
- 3-dimensional stereotest
- Frisby Davis distance stereotest
- Interpupillary distance
ASJC Scopus subject areas