The in vitro assay results showed that patients with severe OM had higher γ-H2AX-specific relative fluorescence at various irradiation doses in the damage kinetics assay, with significantly higher γ-H2AX expression at 8 Gy (p = 0.039), and also at 24 hours after irradiation at a dose of 2 Gy in the repair kinetics assay, compared to the patients with mild OM (p = 0.008). This evidence concerns the gene H2AX and ocular melanoma.