safe tint % ?

nope. 20/10 vision is when an object that is 20 feet away appears as clear as an object 10 feet away for a person with 20/20 vision…

“A visual acuity of 20/20 is frequently described as meaning that a person can see detail from 20 feet away the same as a person with normal eyesight would see from 20 feet. If a person has a visual acuity of 20/40, he is said to see detail from 20 feet away the same as a person with normal eyesight would see it from 40 feet away. It is possible to have vision superior to 20/20: the maximum acuity of the human eye without visual aids (such as binoculars) is generally thought to be around 20/10 (6/3) however, recent test subjects have exceeded 20/8 vision. Recent developments in optometry have resulted in corrective lenses conferring upon the wearer a vision of up to 20/10. Some birds, such as hawks, are believed to have an acuity of around 20/2; in this respect, their vision is much better than human eyesight.”