Table 1. Immunohistochemical analysis of CYP1A1 protein expression in pterygium (n=150) and control^a (n=50) tissues, p<0.0001.

CYP1A1 result	Pterygia, n (%)	Controls, n (%)
Negative	102 (67.0)	48 (96.0)
Positive	48 (33.0)	2 (4.0)

^aFrom superior conjunctiva of 20 patients and medial conjunctiva of 30 patients without pterygium or pinguecula.