<unk>  is a rare condition with an estimated incidence of 3 per million annually. Studies have reported that most patients with<unk>  are older than 60 years of age (32%). Among them, men have a higher occurrence rate in men (60%). Most patients live in rural areas (66%) and are in the lower socioeconomic groups. The age of those with<unk>  ranges from 5 to 89 years, with a mean age of 45.5 years. The mortality rate after<unk>  diagnosis in an investigation of 34 patients with and without immunosuppressive medication is 53% and 5%, respectively.' Another single-centre study involving 46 patients with RA reported a mortality rate of 15%.' Reports have also shown a possibility of<unk>  occurrence after any ocular surgery. In a retrospective study of 771 eyes, 1.4% of participants reported developing late-onset<unk>  at an average of 3–6 months after surgery.
Peripheral ulcerative keratitis
Interstitial keratitis
Nummular keratitis
Neurotrophic keratitis
Lattice corneal dystrophy
Diffuse lamellar keratitis
Granular corneal dystrophy
Subepithelial mucinous corneal dystrophy