Aneurysmal volume expansion after endovascular treatment is caused by intra-aneurysmal thrombosis in the early postembolization period. Although postembolization mass effect on cranial nerves and other adjacent structures has been previously reported, we are unaware of reports involving the anterior visual pathway. A 66-year-old woman with a 2-week history of blurred vision without headache was found to have a large, unruptured anterior communicating artery aneurysm. One month after endovascular treatment of the aneurysm with coiling and flow diversion, the patient developed decreased vision in her right eye and a left homonymous hemianopia. Magnetic resonance imaging demonstrated compression of the right optic nerve, chiasm, and edema of the right optic tract. The patient was treated with a course of high dose corticosteroids, and over the course of several weeks, her vision improved and the optic tract edema resolved. We alert clinicians to this rare but potentially reversible visual complication of endovascular treatment of intracranial aneurysms.