116 Central Fixation
mental strain, all such conditions must necessarily be ac companied by loss of central fixation. When the mind is under a strain the eye usually goes more or less blind. The center of sight goes blind first, partially or com pletely, according to the degree of the strain, and if the strain is great enough the whole or the greater part of the retina may be involved. When the vision of the center of sight has been suppressed, partially or com pletely, the patient can no longer see the point which he is looking at best, but sees objects not regarded directly as well, or better, because the sensitiveness of the retina has now become approximately equal in every part, or is even better in the outer part than in the center. There fore in all cases of defective vision the patient is unable to see best where he is looking.
This condition is sometimes so extreme that the pa tient may look as far away from an object as it is possible to see it, and yet see it just as well as when looking di rectly at it. In one case it had gone so far that the patient could see only with the edge of the retina on the nasal side. In other words, she could not see her fingers in front of her face, but could see them if held at the outer side of her eye. She had only a slight error of refraction, showing that while every error of refraction is accom panied by eccentric fixation, the strain which causes the one condition is different from that which produces the other. The patient had been examined by specialists in this country and Europe, who attributed her blindness to disease of the optic nerve or brain; but the fact that vision was restored by relaxation demonstrated that the condition had been due simply to mental strain.
Eccentric fixation, even in its lesser degrees, is so un natural that great discomfort, or even pain, can be pro duced in a few seconds by trying to see every part of an