To further understand the underlying mechanisms through which UVB-blocking contact lenses may ameliorate the symptoms of UVB-induced photokeratitis, immunohistochemical staining was performed to examine the status of four proinflammatory factors, including NF-κB (p65), COX-2, Fas, and Fas L (Figure 4D and E). Here, PTGS2 is linked to photokeratitis.