Current Medical Literature.
Medical News, New York.
Dana says that alienists do not recognize eyestrain, even as a contributing cause. He
has seen a few cases of eyestrain with apparent bad results mentally, in students.
It seemed as if the eyestrain really led to a kind of exhaustion psychosis—a
mental confusion—so that they could no longer read or study, or remember.
This condition was accompanied by apathy and depression and lack of general
interest. The eyes showed refractive errors and secondary muscular strain.
Recovery came very quickly in most cases after rest and proper glasses. He
believes it wise to have the eyes of psychopathic children examined carefully.
After sixteen years of watching he has found hardly any cases in which eyestrain
is an important and direct factor in establishing even a minor psychosis,
though it modifies its symptoms and secondarily adds to the disturbance. The
visual function is largely automatic and spinal, and when the mind is a good
mind, the visual machinery does not overthrow or directly and seriously affect
it. When the mind is unstable or the body weakened, cerebral eyestrain plays
its part; and when the mind is unstable and the visual machinery is very poor,
even spinal and migraine eyestrain may do some harm. Dana suggests that "glassing"
has become something of a minor psychosis. He does not think that our mental
balance and nervous wellbeing are so entirely at the mercy of slight
defects in an organ that has been perfected by millenniums of use and misuse.
Eyestrain and the Psychoses. JAMA. 2004;292(7):873. doi:10.1001/jama.292.7.873-b