Blurry vision with glasses- monocular diplopia-eye redness-gradual. Doc says allergy, steroid drops did not work. Had brain MRI -clear. What is it?

Number of causes. There are several causes of monocular diplopia, from lens to retinal disorders. It might be valuable for you to be referred to an ophthalmologist who can do a detailed examination of front-of-the-eye to back-of-the-eye potential issues.