How Concerned Should I Be About Sudden Episodes Of Blurred Vision, Dizziness, And Near Blindness In One Eye?

Hi I had sudden blurred vision, lightheadedness, flashes of light, almost blind in my left eye, and dizziness. This happened twice a couple of days apart. I had mini gastric bypass in September 2021 and have low iron, low vitamin D. I also just started Concerta 36mg 5-6 times a week. I want to know how concerned should I be about these sudden attacks and what doctors/ specialists to see?