UV Absorbance of the Human Cornea in the 240- to 400-nm Range

To determine the UV absorbance of the corneal layers (epithelium, Bowman layer, stroma) in the 240- to 400-nm range. Consecutive slices (100 microm) of human cadaveric corneas were cut, and the UV absorbance of each sample was determined in a scanning spectrophotometer. In some cases the epithelium was scraped off and its absorbance measured separately. The investigation of the UV-B absorption of consecutive corneal slices revealed evidence that UV-B absorption is 1.8 times higher in the anterior 100 microm of the human cornea than in the posterior layers. The UV absorbance of the posterior layers was uniform, showing no further structural dependence. The epithelium and Bowman layer are both effective absorbers of UV-B radiation. These results suggest that the anterior corneal layers are particularly important in preventing damage by UV-B radiation.