When is Blepharoplasty Medically Necessary?

From your description, it may be that
your drooping upper lids are causing problems with your vision and
this may be considered a medical condition that could be covered by
insurance. Your first step is to be evaluated by an ophthalmologist,
who will administer a visual field test. Even if the surgery is not
deemed medically necessary, I highly recommend your consulting with a
facial plastic surgeon because at minimum the drooping lids are
causing you fatigue and distress, and should be remedied. I hope this
helps.

Your description of your eyelids covering your eyes and blocking your vision is the typical case that gets covered by insurance. It will be necessary to prove your vision loss with in office testing (visual fields). See an oculoplastic surgeon who can evaluate your eyelids, do the testing and tailor a treatment plan individualized for your particular issues. 

Blepharoplasty is designed to correct upper and lower eyelid aging.  Visual field testing can determine if this procedure is medically necessary.  

Unless it's for health reasons, insurance doesn't usually cover eyelid surgery since it's considered cosmetic. However, for your situation, you may be able to get it covered because your vision is impaired.

Upper eyelid surgery may get considered medically necessary if it interferes with your vision.  This can be determined by having a test called a visual field exam, which most insurance companies will require to document the visual problem.  To be sure, contact your insurance company to determine what tier policy requires.