When my prescription reading glasses snapped in two without warning in November 2016, I had no idea how much my life was about to change.

I went to a local optometrist in Austin, thinking I’d get a quick replacement after a cursory checkup. But a few minutes into the exam, the doctor gave me some sobering news: the cloudiness in my left eye was actually a small lesion on the retina, the inner lining of the eyeball. It was likely...