recurrent keratoconus after penetrating keratoplasty

purpose: to report a case of recurrent keratoconus after penetrating keratoplasty (pk). patient and findings: a 31-year-old male patient who had undergone pk in his right eye for keratoconus 10 years ago presented with gradually decreased vision in the right eye. clinical, topographic, and histopathologic features of the cornea including irregular myopic astigmatism, central and paracentral corneal thinning, and foci of break and fragmentation in bowman's layer were in keeping with the diagnosis of keratoconus. conclusion: slow recurrence of keratoconus characteristics in the corneal graft after pk may result from graft repopulation by recipient’s keratocytes, graft aging or both and may occur along with the process of cellular invasion from the recipient and renewal of resident cells.