The rudest awakening in Optometric science I ever experienced was in watching a radical change in the amount of astigmatism through the ophthalmometer. Patient was a lady, in the thirties, who had been operated on twice for convergent strabismus. Both the internal recti had been cut and indications were that both muscles were either detached or else attached so far back as to be useless.
The left eye, which was the poorer of the two, showed a minimum of 3.00D. of Ast. against the rule, and this amount would actually double for a few seconds and then return to the minimum. This change was evidently due to some action of the oblique muscles and occurred when the eye was directed toward the tube, while there was a slight turning of the head.
The case is of no practical interest except in showing the possibility of corneal astigmatism being functional rather than structural. Another case was that of a lady, also in the thirties, who came to me wearing plus .75 spheres. These were fitted by the assistant to one of the foremost oculists in Kansas. The chief symptom complained of was excessive lachrymation. In this case the ophthalmometer showed .75D. Ast. plus, axis approximately 90, subjectively, plus spheres unacceptable. Also, please note, in the subjective testing, the axis varied markedly and .50D. plus cylinders were preferable to .75D.
After six or seven vigorous muscle treatments, the ophthalmometer showed a decrease in Ast. Subjectively, there was no hesitation in finding the axes 75 and 105. The cylinders were cut to .37 and, to my surprise, patient also accepted a 1.25D sphere for each eye. The excessive lachrymation which has been usually attributed to Ast. began to lessen immediately after the second muscle treatment. This seemed significant.
The first case mentioned above belongs to the freak class, and a similar one might not be met with again in years. The second case, however, is typical of several met with in the last few years, and should furnish food for serious thought. More and more, I am convinced that much suffering and many mistakes in refracting are due to failure to give the external muscular system proper attention.
Excuse the apparent digression, but the point I want to bring out is: That corneal astigmatism does change and often lessens and sometimes disappears after thorough muscle treatments.
Likewise, the symptoms attributed to refractive errors often vanish after muscular treatments, even through the refractive error remains. In other words, the symptoms may be due to wrong muscular condition and not to the refraction. This will account for some of the "miraculous" cures made by the kind of doctors whose slogan is "throw away your spex."