It's really cool that your dad is having success with his vision from iodine. It's good also for his MD, because the MD may learn a thing or two and pass it on. This may impact many more people because of your efforts. The ciliary body of the eye is the middle layer of three in the eyeball and is itself a storage location for iodine, although very few are aware of this. I believe that many eye problems in folks who are iodine-deficient can be remedied, at least in part, by enabling the body to put the Iodine back in there. I'm one example of that -- I can read the finest of printed materials now, whereas previously I needed reading glasses for several years.
Of course one should NEVER put Lugol's solution in the eyes, or any other material that is not specifically formulated to be put in the eyes. Iodine is naturallly present in many foods, and it is the stomach that seems to be the natural route.