In cases where macropsia affects one eye resulting in differences in the way the two eyes perceive the size or shape of images, the condition is known as aniseikonia. Aniseikonia is known to be associated with certain retinal conditions. Epiretinal membrane has been found to cause metamorphopsia and aniseikonia. Vitreomacular traction caused by the excessive adhesion of vitreous fluid to the retina is related to aniseikonia due to the separation and compression of photoreceptor cells. Macular edema and surgical re-attachment for macula-of rhegmatogenous retinal detachment can also cause an increased separation of macular photoreceptor cells resulting in dysmetropsia. Retinoschisis is another eye disease that has been shown to cause aniseikonia.
There is evidence that a lesion appearing in the posterior area of the ventral occippitotemporal visual pathway can cause macropsia. This lesion can be due to an ischemic cell death after an acute posterior cerebral infarction.