• An unfavorable outcome is defined as recurrence of neovascularization arising from the retinal vessels and requiring re-treatment (in either eye) before the infant reached 54 weeks PMA (window of 50 to 70 weeks). [ Time Frame: 54 weeks postmenstrual age (window of 50 to 70 weeks) ] [ Designated as safety issue: No ]
  

• Determination of visual acuity, visual field, refraction, motility examination or any other ocular parameter related to severe ROP [ Time Frame: Five years of age ] [ Designated as safety issue: Yes ]
  

This phase 2 study will assess the anti-neovascularization activity of intravitreal bevacizumab, as determined by regression of neovascular vessels of retinopathy of prematurity (ROP), in neonates with acute stage 3 ROP in zone I or posterior zone II with plus disease. This study will enroll confirmed cases of vision threatening ROP (between ETROP and CRYO-ROP) which have definite plus disease. This will be done because of the controversy regarding determining plus disease and the increasing concern that many infants are being treated whose ROP would spontaneously regress. Bevacizumab will be administered intravitreally using 0.625 mg (0.025 ml) injections into each eye. There is no intent to give additional doses unless there is a recurrence of vision threatening stage 3 ROP with plus disease since the disease is self limited by completion of vascularization. Clinical response and any evidence of ocular toxicities will be documented by RetCam retinal images taken pre-injection, one week and one month post injection, and at 6 months of age (54 weeks postmenstrual age)(window of 50 to 70 weeks PMA)(primary outcome) and at 12 months of age (80 weeks postmenstrual age)(window of 75 to 100 weeks PMA)(structural documentation). RetCam fluorescein angiograms will be taken when possible to document structural outcomes in greater detail. Any evidence of systemic toxicities will be documented by appropriate clinical and laboratory tests.