To report a case of nonarteritic anterior ischemic optic neuropathy (NA-AION) with an atypical visual field defect after intraocular surgery. Case summary

A 61-year-old male presented with a visual field defect in his right eye 1 day after uneventful cataract surgery with pars plana vitrectomy for epiretinal membrane. His best-corrected visual acuity (BCVA) in the right eye was 20/400 with a relative afferent pupillary defect. A color vision test revealed failure only in the right eye. A slit-lamp examination revealed no abnormality in the anterior part of the eyes. A fundoscopic examination also revealed no abnormality in the posterior part of the eyes, including the optic disc. The Humphrey visual field test revealed a nasal vertical defect in the right eye. Orbital and brain magnetic resonance imaging were normal. After 14 days from the initial symptom, fundus photography and optical coherence tomography revealed an optic disc swelling and splinter hemorrhage. Fluorescein angiography revealed a delayed filling on the temporal half of the optic disc and inferotemporal peripapillary choroid. A diagnosis of NA-AION was made. The patient was treated with oral steroids and aspirin. After 3 months, the BCVA was 20/125. The visual field defect was maintained and segmental atrophy developed on the superior and inferior sides of the right optic disc. Conclusions

AION may present as vertical hemianopsia. With the risk factors of ischemic optic neuropathy, the possibility of AION should be considered in the differential diagnoses of postoperative visual impairments or field defects after intraocular surgery.