Knudsen's two hit hypothesis is for
Knudson gave the hypothesis that there are two mutations needed for Retinoblastoma to manifest. Either both hits are on somatic cells or one is at the somatic cells and one is at germ cell. Respectively, it can be sporadic or a hereditary case Refer khurana 6/e p 303
Glaucoma
Retinoblastoma
Optic glioma
Meningioma
General anatomy