To report a case of bilateral diabetic papillopathy related to rapid hemoglobin A1c (HbA1c) decrease in a type I diabetic patient.

A 39-year-old female who was diagnosed with type I diabetes mellitus for the first time at this hospital was presented to our clinic for evaluation of diabetic retinopathy. There were no subjective symptoms, including blurred vision or visual defect. Her best corrected visual acuity in both eyes was 1.0, but her fundus resembled mild nonproliferative diabetic retinopathy. When diagnosed with type I diabetes mellitus, her HbA1c was 15.3%. She used insulin to control her blood glucose and her HbA1c reached 7.3% two months after controlling the blood glucose. Three months after her diabetic diagnosis, there were no differences in subjective symptoms and best corrected visual acuity. Fundus examination showed optic disc swelling in both eyes. To evaluate for the etiology of optic disc swelling, we did the examinations of the optic disc, fundus, and brain magnetic resonance imaging. No specific signs were observed. We diagnosed diabetic papillopathy and observed the patient without any treatments. Her optic disc swelling showed gradual improvement.

This case shows that the rapid HbA1c decrease in type I diabetes mellitus is related to the occurrence of bilateral diabetic papillopathy. This supports previous studies that estimated that the rapid HbA1c decrease in type I diabetes mellitus in response to insulin treatment is one of the risk factors for bilateral diabetic papillopathy.