Figure 5. Low physiologic oxygen conditions are associated with the greater size and circularity of choroidal melanocyte nuclei. A: Circularity of the nuclei was determined in choroidal melanocytes exposed at 21% or 3% O₂ (n = 3) by analyzing a minimum of 500 nuclei per condition with ImageJ and the following formula: 4π × [Area] / [Perimeter]². The circularity ranged from 0 (infinitely elongated polygon) to 1 (perfect circle). B: The area of the nucleus (µm²) was measured in choroidal melanocytes grown under hyperoxia and low physiologic oxygen conditions by analyzing a minimum of 500 nuclei per condition with ImageJ. Data are presented as a cumulative percentage using parts of whole vertical slice graphs. Representative fields of DAPI-stained nuclei of choroidal melanocytes exposed to 21% or 3% O₂ are shown on the right-hand side of the panels.