[A new method to quantify subjective aniseikonia].

PURPOSE To design subjective aniseikonia measuring criteria in order to quantify its value and to use it to the clinical practice. MATERIAL AND METHODS In order to carry out the aniseikonia measurements, a sinoptophore (Clement Clark) was used and two tests (one per eye of each patient) were performed. A viewfinder capable of measuring the difference in size between subjective images in both eyes was used and a percentage scale of ratio between 0 and 30%, with an accuracy of 1% was developed. An observational descriptive study was performed on 358 patients, and a complete ophthalmological examination also performed. The patients were divided in 3 groups: emmetropic patients, ametropic patients with non-progressive spectacles, and ametropic patients with hydrophilic contact lenses. RESULTS Of the 358 patients studied, 22.7% were men and 67.3% women. The average age was 38.3 (SD 17.3) years. 40.2% of the patients were emmetropic and 59.8% had some type of ametropia. When analyzing the refractive defect measured as the spherical equivalent we found a higher prevalence of myopia than hyperopia. The level of aniseikonia in the group of emmetropic patients was 1.6% (SD 3.11), in patients with glasses was 1.3% (SD 2.81), and in patients with contact lenses was 1.1% (SD 2.96). Comparing the results of aniseikonia in anisometropic and emmetropic patients, no statistically significant differences were found. CONCLUSION A simple method to quantify subjective aniseikonia, useful in clinical diagnosis has been designed.