Effects on Aniseikonia of Differences in Distance Measurement

Abstract

Purpose: The purpose of this study was to examine whether aniseikonia is influenced by differences in distance measurement.

Method: Subjects comprised university students with the same refractive power in both eyes with voluntarily participated in this study. Artificial aniseikonia was produced using afocal size lenses of 0%, 2%, and 4%, added in random order before the left eye. The subjects were then asked to observe the new aniseikonia test (NAT) targets located at 50cm and 5m distance. Aniseikonia was measured by the complete up and down method.

Results: The main effect of difference in distance measurement was statistically significant (p < 0.01). Aniseikonia in the distance was perceived on average to be about 1.5 times larger than that in the near.

Conclusions: When treating the complaint of headache or asthenopia in the distance, such as in driving, we should not depend only on measurement of aniseikonia in the near.