Photodamage of the conjunctiva in patients with porphyria cutanea tarda.

Ninety two patients with porphyria cutanea tarda (PCT) were examined ophthalmically in a paired case control study. The incidence of pinguecula and of pterygium was 8 and 2 times higher respectively, in PCT patients than in the control group. The photodamage to the conjunctiva is considered to be a result of the photoactivity of uroporphyrin in the tissues.