Hello, Cataract surgery is one of the most commonest surgeries done world wide and most of the times it yields very good results. Very few incidences of loss of vision are noted either because of pre existing reasons or because of surgery induced problems. In your husbands case as from your history, he has painful loss of vision. It ca be because of post operative corneal edema which is because of damage to the innermost layer of cornea either preexisting or during surgery. This can be treated by medical treatment in the mild and early cases and later by surgery in the form of corneal replacement surgeries or keratoplasty. The second commonest cause may be because of glaucoma which can be managed by medical drugs or by surgery. The other causes are inflammation of the inner layers of the retina called as cystoid macular edema, which can be treated by medical management in most of the cases. He has to consult ophthalmologist at the earliest to find out the underlying cause and management accordingly. Thank you