Aniseikonia and visual functions with optical correction and after refractive surgery in axial anisometropia

Abstract PURPOSE To evaluate differences in the subjective aniseikonia and stereoacuity in patients with axial anisometropia after full correction of the refractive error with spectacles. contact lenses, and refractive surgery.METHODS A prospective study was performed in Cairo University Hospitals on 20 patients with axial anisometropia caused by unilateral myopia > 5 D with > 4 D inter-ocular difference in spherical equivalent who were suitable candidates for excimer laser ablation (LASIK) or implantable collamer lens implantation (ICL) were included. All patients had measurement of corrected distance visual acuity (CDVA), fusion, and stereoacuity testing, and measurement of aniseikonia with spectacles, contact lenses, and after surgery.RESULTS Mean age at time of surgery was 25.7 ± 3.1 years. There were no statistically significant differences in the CDVA or stereoacuity with spectacles, contact lenses, or after refractive surgery. Microkonia < 5%) was perceived with spectacles in 8 patients (40%) and remained unchanged in 7 of these 8 patients with contact lenses. Following LASIK (n = 11), there was macrokonia < 2% in 4 patients (36%), persistent microkonia of 3% in 1 patient (9%), and no change in image size in 6 (55%) patients. Following ICL implantation (n = 9), there was perceived macrokonia of 2% in 4 patients (44%), disappearance of microkonia in 1 patient (11%) and no change in 4 patients (44%).CONCLUSIONS Differences in CDVA, stereoacuity, and aniseikonia after correction of anisometropia by glasses, contact lens and surgery are both clinically and statistically significant. Retinal or neural adaptation might have a role in correction for differences in image size.