The final surgical procedure provided you have all the pertinent information - is completely up to you. Improvement of the left eye alone - is prob preferable since you do not have issues with the right eye
If anything you only have mild ptosis, I don't think it would be considered medical. Your eyelid margin needs to be less than 2mm from the midpoint of your pupil to be considered medical.Having said that, you would probably benefit from ptosis correction if you were to have an upper blepharoplasty.
Your photographs are rather limited, but it does appear that you may have ptosis on your upper eyelids, which is a weakness of the eyelid muscle. Ptosis repair is usually performed by a ocular plastic surgeon. A cosmetic blepharoplasty procedure will not help with this issue.
