Background: Orbital cellulitis is an infection of the ocular adnexal and orbital tissues behind the orbital septum. The complications are poor prognosis. This paper is to describe some severe rare complications of orbital cellulitis. Case presentation: A case of 32-year-old female presented with acute severe progressive orbital cellulitis on the right eye after a black fly (Simuliidae spp.) bite. Orbital imaging with computed tomography and magnetic resonance imaging showed eyelid abscess with orbital abscess formation and superior ophthalmic vein thrombosis. She was promptly treated with intravenous vancomycin, piperacillin and had surgical procedures to release orbital pressure including lateral canthotomy, lateral cantholysis, and eyelid with orbital abscess drainage. Pus collection culture was positive for Staphylococcus aureus. Even though she responded well to antibiotics treatment, progression involved severe orbital inflammation with marked increased orbital pressure, and her visual acuity was such that she had no light perception. Combined central retinal vein, central retinal artery and cilioretinal artery occlusion were identified. Fundus examination showed retinal whitening at the posterior pole and a few scattered flame-shaped retinal hemorrhages. The cilioretinal artery presented with perivascular retinal whitening. A fundus fluorescein angiogram revealed cilioretinal and retinal artery filling delay and also delayed arteriovenous transit time. She also developed an ischemic macular hole after a week of treatment. We demonstrate an optical coherence tomography image showing the intact posterior hyaloid membrane that represents no traction on the macula to support the ischemic cause. Conclusion: Multiple retinal vascular occlusion and ischemic macular hole could be an early complication of severe orbital cellulitis from increased orbital pressure; therefore, close monitoring of visual acuity with IOP, and prompt treatment when indicated might reduce the risk of consequent blindness.