We report a patient who developed a subperiosteal orbital abscess due to acute aggravation of chronic sinusitis, that resulted in vision loss. A 30-year-old female patient who presented with right eyelid swelling and pain was diagnosed as having right orbital cellulitis. CT revealed a right subperiosteal orbital abscess. The visual acuity on the right side was below the light perception level, and the patient also had marked exophthalmos and corneal opacity. Based on the CT and MRI findings, we diagnosed the patient as having rhinogenic orbital complications. We performed endoscopic sinus surgery with external incision for the purpose of drainage of the subperiosteal orbital abscess and creation of a pathway for drainage. After postoperative antibiotic and steroid therapy, the eyelid swelling and pain improved, but the visual impairment persisted. Therefore, optic nerve decompression was performed and a second course of steroid pulse therapy was administered, however, the visual impairment still persisted. Acute aggravation of chronic sinusitis can manifest as various symptoms due to the spread of inflammation to the surrounding tissues. In some patients, irreversible optic nerve damage can occur within a short time, and markedly impair the quality of life of the patient. The interval from onset to surgery, the preoperative visual acuity, the optic disc findings, and the extent of visual field defects are all prognostic factors for the visual acuity. Accurate and rapid diagnosis and treatment are required to avoid permanent visual impairment.