Surgery and intrastromal injection. (a) The corneal flap is held tense with the aid of toothed forceps, and the filamentous white collagen fiber could be seen clearly. (b) Corneal scissors were used to trim the edge to make the edge of wound smooth. (c) The needle was advanced towards the lesion center in parallel with the stroma. (d) Liquid was slowly pushed into the stroma until the inflated stroma exceeded the edge of the lesion by more than 0.5 mm.