Have glaucoma w/thinning optic nerve. dr says visual field normal & shading at very top of field could be eyelash or eyelid causing it. possible?

Could be: It is very important to have a regular eye exam by your ophthalmologist. If your doc told you that is was normal then its. Some time if the person has a droopy excessive eyelid (dermatochalsis) it may cause an upper visual field defect.

Yes: It's possible to have a lid artifact covering the top half of a visual field. Usually you can tape up lids that get in the way during the test.