Differences in the size of things seen in both eyes may be related to refractive errors, central plasma choroidal retinopathy, age-related macular degeneration and other diseases. 1. Refractive error: if the refractive errors of both eyes are mismatched and have a big difference, for example, if one eye is myopic and the other is hyperopic, and if they are corrected with concave and convex lenses respectively, then there will be a difference in the size of things seen in both eyes. 2. Central plasma choroidal retinopathy: It mainly occurs in the macular center of young and middle-aged people, and the common cause is the emotion fluctuation. The macula is the main part of receiving external visual signals, and the morphological, structural or functional abnormalities occurring in the macula will have an impact on the quality of vision. 3. Age-related macular degeneration: this is a kind of fundus disease whose incidence will increase with age, and it can cause the clinical manifestations of central vision loss and visual distortion, because the lesion involves the macula, so it can lead to different sizes of things in both eyes. It is recommended to consult an ophthalmologist to find out the cause of different sizes of images in both eyes and to treat the problem under the guidance of a doctor’s advice.