Measurement of spectacle-induced aniseikonia in axial anisometropia using the New Aniseikonia Test

Aim To determine whether spectacle correction in axial anisometropes can cause significant aniseikonia. Patients and methods A cross-sectional study was conducted on eight patients who had axial anisometropia with a spherical equivalent difference between both eyes equal or more than 4 D. Aniseikonia was measured using the New Aniseikonia Test 'Awaya.' Aniseikonia of 3% or more was considered clinically significant. Spearman correlation between the amount of aniseikonia and anisometropia was calculated. Results The mean +/- SD age of the patients was 13 +/- 4.64 years (range, 7-24 years). Anisometropia ranging from -14.5 to +5.25 DS with a mean +/- SD of -6.70 +/- 5.18. The overall mean +/- SD of aniseikonia was -1.45 +/- 0.52. Five patients had no aniseikonia, three patients had -1% aniseikonia, and three patients had -2% aniseikonia. Spearman correlation showed an insignificant positive correlation between the amount of anisometropia and aniseikonia (r=0.05, P=0.86). Conclusion Among our cases, spectacle correction in axial anisometropia did not lead to significant aniseikonia using the New Aniseikonia Test. Aniseikonia should be assessed in patients with anisometropia as 1% of aniseikonia per diopter of anisometropia does not apply in every case.