People on this med are warned of these risks and are monitored by a retinal specialist every 6 months while taking it. They also take a bigger dose than is necessary to treat COVID. Source for my info is that I took this for years and have a bunch on hand from when I quit taking it. I used to take 400 mg/day every day. The dosing for COVID prevention and treatment are a little different, because you take a lot for the first couple of days but then only take one dose a week. https://www.reddit.com/r/medicine/comments/fbfj0r/covid19_prophylaxis_in_healthcare_workers/?utm_source=BD&utm_medium=Search&utm_name=Bing&utm_content=PSR1