Actually, I've off and on practiced a form of Yoga called Surya (or Sungazing) for over four decades. Although you don't stare at the sun when it's right above (usually just the first 20 degrees in the morning and the last 20 degrees around sunset), I can stare directly at the sun without blinking. Even though I don't live in the UK and can actually SEE the sun! ?
Also, I'm now in my 60's and still have 20/10 vision (i.e., "better" than perfect)!
YMMV.