Eye Surgery and Blurred Vision? Options?

My Dad had surgery to his left eye 6 mos ago to remove scar tissue from a procedure done several years back. Before the surgery he had 20/20 vision, but since he's had continued blurred vision in that eye. He had a MRI on the optic nerve but it was clear. Is it normal to have blurred vision this long after surgery and is there anything he can do to correct it. Thank you.