Figure 2 of Park, Mol Vis 2011; 17:3468-3480.

Figure 2. Anterior segment photographs of representative pterygium cases. Upper panels (A-C) demonstrate cases 6, 10, and 16. The surface vascularity of these pterygia was scored as +++. These cases revealed strong cyclooxygenase (COX-2) expression both in the epithelial and stromal layers. Lower panels (D-F) demonstrate cases 11, 13, and 15. These pterygia look slightly atrophic, and the vascularity was scored as ++. Relatively fewer COX-2-expressing stromal cells were found in these cases compared to cases of the upper panel. The surface vascularity of pterygium was scored as score +, minimal visible vessel (equal to conjunctiva); score ++, moderate vascularity (more dense than conjunctiva); and score +++, severe vascularity with vessel congestion.