Hair loss, brittle cracked nails, glared vision. Any ideas?

22 year old male in normal physical shape (190 pounds, 6 feet 1 inch tall) In the past 5 days I have lost a 1.5 inch in diameter circle of hair on top of my head. In the past couple of months I have been loosing the hair that used to grow on my beard. I have brittle, cracked nails since 2.5 years now both of my thumbs have vertical cracks that have remained all this time. I was wondering if their could be an underlying cause for this. Also, 2 weeks ago I have had a 20 minutes phase during which the peripheral vision of my left eye was darkened and somewhat "glared"; as if there was a camera flash in my eye but nothing like that had happened.