My son developed fairly severe vision problems several weeks ago and has since seen an optometrist, ophthalmologist, and pediatric ophthalmologist. Standard exams have revealed nothing definitive and he is currently (tentatively) scheduled for ERG and IVFA exams. Since his last appointment, his vision has returned to normal and the doctor said that if that happened, the tests could be cancelled. His current glucose level (as per pump records) averages 210 mg/dl [11.6 mmol/L] and his most recent A1c was 9 (7 last spring). He currently lives with his mother and started a vegan (no animals, eggs, dairy) diet about two or three months ago. Do you have any comments? What questions should we ask at his follow-up appointment?

It is not clear from your description what sort of “severe vision problem” your son developed. Was it burry? Did he have visual field defects or total vision loss? Were your son’s pupils reactive? What was the onset, quality and duration of symptoms? The problem may or may not have anything to do with diabetes whatsoever. The tests recommended (ERG and FA) suggest that they were trying to rule out inherited diseases (e.g., retinitis pigmentosa or Leber’s Hereditary Optic Neuropathy, to name two of many possibilities). The vegan diet may be a red herring, but makes me think of Leber’s. The fact that the vision has returned to “normal” (has it really?) is curious. It could be blood sugar affecting refractive error, but you certainly don’t need an ERG or FA to diagnose that, though they may be helpful.

PC