Cavernous hemangioma of the retina and optic disc is a rare lesion that was first defined as a distinct entity by Gass in 1971. It is usually easily recognized by its characteristic appearance of saccular "grape-like" lesions. On fluorescein angiography, plasma-erythrocyte separation is seen. Two patients with cavernous hemangioma of the optic nerve were examined over a period of 5 to 10 years. Although these tumors are usually considered to be static and not capable of growth, these two cases of cavernous hemangioma of the optic nerve showed documented growth. One case required vitrectomy for vitreous hemorrhage. Cavernous hemangioma of the optic disc can grow and can cause vitreous hemorrhage severe enough to require vitrectomy.