Once the famous German physiologist Herman Helmholtz, walking through the park, saw a crying girl. It turns out that there was a sickle in the eye.
The scientist took out the pocket lens and began to look through it to the child’s eye.
Suddenly he noticed that in a certain position the lens rays fell through the pupil on the back wall of the eye and brightly illuminated it. Helmholtz immediately understood the importance of this phenomenon; he improved the randomly opened method and invented the eye mirror - an unchanged attribute of the modern eye doctor.
Then you say, “Tears won’t help.”