Corneal lipofuscinosis--clinicopathologic study of 10 patients

Abstract

Lipofuscin pigments are considered indigestible residues of lysosomal activity associated with aging. We present the clinical and histopathological features of ten patients with corneal lipofuscinosis. Ten patients (five female, five male, mean age 62 years, range 53 to 77 years) underwent penetrating keratoplasty for vascularized corneal scars. The clinical diagnoses were herpes simplex keratitis (5), zoster keratitis (1), phlyctenular keratitis (1), immunologic graft rejection (2) and corneal injury (1). The mean duration of disease was 6.5 years (range 3 to 11 years). On slit lamp examination both linear and diffuse deposits of yellow pigment were noted in the corneal stroma. All corneal buttons were processed for histopathologic and electron microscopic studies. The areas of yellowish pigmentation in the corneal stroma corresponded histopathologically to clusters of macrophages, keratocytes and occasional giant cells containing PAS-positive granules. The granules measured 1 to 3 micrometers and were also present extracellularly. Results of Gram stain were negative, but the material showed vivid autofluorescence. Corneal lipofuscin can be detected at the slit lamp as focal or diffuse yellowish deposits in both the superficial and deep corneal stroma of patients with long-standing keratitis. This is in contrast to corneal iron deposits, which appear as yellowish pigment in the corneal epithelium. The identification of corneal lipofuscin is possible using histochemical and autofluorescent studies. Further studies should address whether corneal lipofuscin predisposes to suture loosening.