Morphometry of the corneal endothelium in glassblowers compared to non-glassblowers

Acute exposure to high levels of IR radiation (IRR) can damage the endothelial cell layer of the human cornea, but the impact of chronic lower-dose exposure has not been assessed objectively. The corneal endothelium of 10 individuals who had occupational exposure to IRR as glassblowers (average 16 years) was examined by photo-slitlamp biomicroscopy, the endothelial mosaic assessed by morphometry, and compared to 10 non-glassblowers (controls). The analyses reveal the glassblowers to have higher than expected endothelial cell density (ECD, average 3371±304 cells/mm2 compared to a control value of 3072±198 cells/mm2), a higher variance in cell area, and a lower percentage of the most-prevalent cell type, i.e. the six-sided cells (average 52.0±12.2%, compared to controls of 64.1±6.6%). Analyses of the sizes of different cell types (four-, five-, six-sided, etc.) indicate that the cells in both groups are proportionately larger as the number of sides increases, but that this area–side relationship is different in the glassblowers, who had both smaller and larger cells compared to controls. Two other cases had even higher cell density values (>5000 cells/mm2) and <50% six-sided cells. Occupational exposure to a mixture of IRR, perhaps some UVR as well as thermal convection effects, can apparently result in morphological changes in the human corneal endothelium. These may be the result of IRR-stimulated cell division.