Stages There are 4 stages of disease, with stage 4 being the rarest and most severe. * Stage 1 Cells infiltrate the periphery of the flap, without involving central cornea. * Stage 2 Peripheral cells migrate to the center of the cornea, and impair vision; presentation is usually 2 to 3 days after surgery. * Stage 3 Cells at the central cornea form clumps of dense cell aggregates. * Stage 4 Otherwise known as central toxic keratopathy, stage 4 characteristically has no inflammatory cells at the anterior chamber or cornea, but there is central stromal necrosis, and the cornea becomes opacified; onset is usually 3 to 9 days after refractive surgery.
Diffuse lamellar keratitis
Nummular keratitis
Interstitial keratitis
Peripheral ulcerative keratitis
Neurotrophic keratitis
Fungal keratitis
Lattice corneal dystrophy
Herpes simplex keratitis