Stage 4 DLK is indeed quite rare and I am unaware of any published series. I can relate my one case of Grade 4. The patient was -7 preop, had unclomplicated LASIK in his first eye (I always do one eye at a time so he never had surgery on the second eye and still hasn't). His DLK rapidly progressed from Grade 1 to Grade 4 about 4 years ago despite agreesive treament and a flap lift and wash out. Due to enzymatic digesting of his corneal stroma from the inflammation he became hyperopic to +7 but had good vision with this correction despite the typical mud crack folds in the superficial cornea. He gradually became less and less farsighted and the folds are now almost completely cleared and now at about 4 years he is +2 correctable to 20/25 and he wears contacts in both eyes. He is considering touching up his first eye with PRK and maybe doing PRK on his second eye.