Hi, it looks like one of your upper eyelids does not have a visible crease and the other side has a slightly obscured crease. This is due to your eyelid anatomy having natural fullness and a lower crease position. I would recommend having an upper blepharoplasty with lid crease reestablishment....
You are right that Canthopexy is not used for scleral show. However, the other mentioned procedures can be appropriate for it depending on the cause. You need to see a plastic or ophthalmic plastic surgeon who is an expert in this.
Blepharoplasty is used for eyelids that have too much skin. This is not what you have. Canthopexy is used in conjunction with a blepharoplasty when your lids are also lax. This would not apply to you if you do not need a blepharoplasty. What you have is loss of volume across the orbital rim....