Thanks for the great question. Orbital and globe (eyeball) anatomy is extremely complex 3-dimensionally, and there are many factors that can be contributing to one eye appearing larger/smaller than the other. Significant asymmetry of the eyeballs themselves is not terribly common, it's much more likely that there is a bony asymmetry or overall orbital volume difference that is causing relative malposition of one of your eyes making it appear smaller than the other, i.e. it's sitting farther back than the other, lower than the other, etc. However, without photographs to view, it's impossible to narrow down what may be the cause of your concern and following the best course of action. Even with pictures though, you should consult with a board certified plastic surgeon or occuloplastic surgeon for a thorough exam, history and assessment of the cause of the eyeball asymmetry. Depending on the findings, your doctor can then describe what is most likely the cause of your concern and what are the various surgical/nonsurgical options for correction. Best of luck!