Ophthalmomyiasis interna with invasion of the optic nerve

Purpose: To report a case of ophthalmomyiasis interna with optic nerve invasion that was treated with oral ivermectin and prednisone. Methods: Case report with retrospective review of medical records and multimodal imaging studies. Results: A Christmas tree farmer in his sixties presented with expanding multicolored, spiraling photopsias in the left eye. The visual acuity measured 20/50, and examination and imaging findings showed subretinal tracks consistent with ophthalmomyiasis interna. After several weeks of spontaneous improvement, the visual acuity decreased to 20/150 and fundus examination showed new optic disc edema that was treated with ivermectin and prednisone. Despite the development of optic disc pallor, the visual acuity improved to 20/25. Conclusion: Subretinal fly larvae can occasionally exit the eye by invading the optic nerve. Treatment of optic nerve involvement with ivermectin and prednisone can result in an excellent visual outcome.