Why is my right eye smaller than my left eye? (photo)

You have a very slight difference between the 2 sides.  The photo is not great since it is so far away, but it looks mostly like you have a lower brow on the right.  This will make it appear that you have more skin on the upper lid on this side, so you see less of a platform.  Try a little Botox to the outer brow to elevate the corner and see it that improves the symmetry.   

Thank you for sharing your question and posting your photo. Subtle sdymmetry is natural and probably not related to your other medical condition. The benefits of corrective surgery do not outweigh the risks in your case. See an Oculoplastic Surgeon for in office evaluation. Good luck,

It is quite normal to have two uneven eyes as is apparent from your photo.  Be reassured that you are okay

There is a dictum that "no two sides of the body are exactly the same and they can never be made exactly the same" with or without surgery.So, for example, new shoes don't fit exactly the same on your left and right feet.  Many women's breasts have a slightly different size and shape. Your facial profiles, left and right, are slightly different; which is why some people like to have their photo taken from one side better than the other (their "good side").We are all born with some degree of asymmetry and this may change as we age.  People will notice more asymmetry in their face when they look at themselves in a photograph because it is reversed from the way they see themselves everyday in the mirror.Hope this helps.