AIM: To analyze the impacts of the shape of uveal melanoma on retinal structure. METHODS: Histopathological sections and clinical data from patients with uveal melanoma were retrospectively observed and analyzed, and key indicators including the tumor’s shape, size, height-to-base ratio, retinal thinning and retinal invasion were analyzed. RESULTS: The study included 102 patients (102 eyes) with a mean age of 45.6±12.4y, with 76 (75%) uveal melanomas showing the spindle cell type, 6 (6%) showing the epitheloid cell type, 16 (16%) showing the mixed cell type and 4 (4%) showing predominantly other cell types. Differentiated by tumor locations: 3 cases of ciliary body melanoma (2.9%), 28 cases of ciliary body and choroid melanoma (27.5%), 71 cases of choroid melanoma (69.6%). Retinal thinning was detected in 43 (43%) eyes and retinal invasion by the tumor cells in 86 (84%) eyes. Maximal tumor height ranged between 1.2 and 15.6 (mean: 8.3±3.6) mm, and mean maximal tumor base diameter was 17.3±6.5 (range: 4.8-31.2) mm. Mean R-value as ratio of tumor peak height to maximal tumor base diameter was 0.53±0.32. Mean R-value was significantly higher in the group with retinal thinning (n=43) than in the group without retinal thinning (n=59; 0.69±0.31 vs 0.42±0.27; P<0.01). R-value was slightly, however statistically not significantly (P=0.09) higher in the group with retinal tumor invasion (n=86) than without retinal tumor invasion (n=16) (0.56±0.33 vs 0.41±0.25). CONCLUSION: A high R-value indicating a prominent tumor is associated with tissue thinning in the adjacent retina, and marginally significantly with intra-retinal tumor cell invasion. Shape of uveal melanomas’s corss section is of importance for the secondary involvement of the adjacent retina.