Stage IIIB includes: (T3d, N0, M0); (T4b-c, N0, M0). T3d: Tumor size category 3 with ciliary body involvement and extraocular extension less than or equal to 5 mm in largest diameter. T4b: Tumor size category 4 with ciliary body involvement. T4c: Tumor size category 4 without ciliary body involvement but with extraocular extension less than or equal to 5 mm in largest diameter. N0: No regional lymph node metastasis. M0: No distant metastasis. (AJCC 8th ed.) [from NCI]