<qa>  What is the growth factor that is important for the formation of new blood vessels?This study will test the ability of the experimental drug EYE001 to reduce retinal thickening and improve vision in patients with Von Hippel-Lindau syndrome VHL. Angiomas blood vessel tumors commonly develop in the back of the eye on the retina and the optic nerve in patients with VHL. Although the tumors are not cancerous, they may cause significant vision loss. Current treatments, including laser therapy, cryotherapy, and vitrectomy, may not be successful or possible for all patients. EYE001 decreases production of VEGF, a growth factor that is important for the formation of new blood vessels and that is elevated in VHL. Preliminary findings from studies of other retinal diseases suggest that EYE001 can reduce retinal thickening and improve vision. 