[...Lying a Cause of Myopia

I may claim to have discovered the fact thai telling lies is bad for
the eyes. Whatever bearing this circumstance may have upon the
universality of defects of vision, it can easily be demonstrated that
it is impossible to say what is not true, even with no intent to
deceive, or even to imagine a falsehood, without producing an error of
refraction.

If a patient can read all the small letters on the bottom line of the
test card, and either deliberately or carelessly miscalls any of them,
the retinoscope will indicate an error in refraction. In numerous
cases patients have been asked to state their ages incorrectly, or to
try to imagine that they were a year older, or a year younger, than
they actually were, and in every case when they did this the
retinoscope indicated an error of refraction. A patient twenty-five
years old had no error of refraction when he looked at a blank wall
without trying to see; but if he said he was twenty-six, or if someone
else said he was twenty-six, or if he tried to imagine that he was
twenty-six, he became myopic. The same thing happened when he stated
or tried to imagine that he was twenty-four. When he stated or
remembered the truth his vision was normal, but when he stated or
imagined an error he had an error of refraction.

Two little girl patients arrived one after the other one day, and the
first accused the second of having stopped at Huyler's for an ice-
cream soda, which she had been instructed not to do, being somewhat
too much addicted to sweets. The second denied the charge, and the
first, who had used the retinoscope and knew what it did to people who
told lies, said

"Do take the retinoscope and find out."

"I followed the suggestion, and having thrown the light into the
second child's eyes, I asked:

"Did you go to Huyler's?"

"Yes," was the response, and the retinoscope indicated no error of
refraction.

"Did you have an ice-cream soda?"

"No," Said the child; but the tell-tale shadow moved in a direction
opposite to that of the mirror, showing that she had become myopic and
was not telling the truth.

The child blushed when I told her this and acknowledged that the
retinoscope was right, for she had heard of the ways of the uncanny
instrument before and did not know what else it might do to her if she
said anything more that was not true.

The fact is that it requires an effort to state what is not true, and
this effort always results in a deviation from the normal in the
refraction of the eye. So sensitive is the test that if the subject,
whether his vision is ordinarily normal, or not, pronounces the
initials of his name correctly while looking at a blank surface
without trying to see, there will be no error of refraction; but if he
miscalls one initial, even without any consciousness of effort, and
with full knowledge that he is deceiving no one, myopia will be
produced...]

- Dr. W. H. Bates, September 1919