Fig. 4From: Toxicity of Povidone-iodine to the ocular surface of rabbits(above) Comparison of the severity of squamous metaplasia according to Nelson grading system among the four groups. Significant differences were noted between the control and 10-min PI group, the 1-min and 3-min PI group and the 1-min and 10-min PI group on day 3, and between the control and 3-min PI group, the control and 10-min PI group, the 1-min and 3-min PI group and the 1-min and 10-min PI group on day 7. Data show means ± SDs (the error bars). Day 0 indicates the day immediately after povidone-iodine instillation. * p < 0.05 (Steel–Dwass test for the differences among the three PI groups). (below) Representative images from conjunctival impression cytology of each group performed on day 7. a In the control group, the conjunctival impression cytological grade is 0. The epithelial cells are small and rounded. The nuclei are large, and stained with hematoxylin, at a nucleocytoplasmic ratio of 1:2. The abundant goblet cells are plump and oval with an intensely PAS-positive cytoplasm (400X). b In the 1-min PI group, the cytology grade is 0–1. The epithelial cells are slightly larger than control cells and more polygonal in shape. Goblet cells are abundant. c In the 3-min PI groups, the cytology grade is 2–3. The epithelial cells are slightly larger and more polygonal in shape. The nuclei are smaller, and have a nucleocytoplasmic ratio of between 1:2 and 1:3. Goblet cells numbers are markedly decreased. d In the 10-min PI group, the epithelial cells are larger and more polygonal. The nuclei are smaller and have a nucleocytoplasmic ratio of between 1:4 and 1:5. Goblet cells are scanty. Bar: 100 μmBack to article page