What could be causing my eyelids to itch then swell for a year after eyelid surgery? I did not have eye allergies prior (Photo)

I had upper lid eye surgery for droopy eye lids (caused 25% vision loss). This was a year ago. 3 days post op my eyelids swelled so much I was totally blind. I was put on prednisone and antibiotics, cold compresses and it resolved after a few days. A few months later, my eye lids got itchy and swelled up almost as badly. And this repeated itself over and over. My primary doctor prescribed antihistamine eye drops and has told me to see a ophthalmologist. Connected to my surgery?