Effect of Muscular Exercise
This muscular treatment, or constructive exercising, should enable the patient to overcome his amount of four degrees in either direction in about a week. Hence in the case showing 38 degrees for single binocular vision, results may be looked for in about nine weeks—four degrees divided into 38 degrees. While the patient is undergoing the treatment, which is nothing more than the strengthening of the interni muscles or developing adduction, it is natural to believe that the amount of imbalance is likewise being conquered. This, however, is readily determined from time to time by making the binocular muscle test with the phorometer and Maddox rod, as well as the duction chart test ([Fig. 24]), as previously outlined.
To fully appreciate the effect of this muscular treatment, the reader need only hold his head in a stationary position, casting his eyes several times from the extreme right to the extreme left, not failing to note the apparent muscular strain. On the other hand, with the aid of the Ski-optometer’s rotating prisms, the refractionist not only has complete control of the patient’s muscles at all times, but scientifically accomplishes muscular exercise without any tiresome strain, overcoming all possible exertion.
After the case in question has been reduced to 30 degrees, having no further use for the rotary prism, it may be removed from before the right eye and the same exercising procedure continued as before with the remaining left side rotary prism by reducing its power, until it is likewise down to zero.
Having reduced both prisms to zero, each prism should again be placed in position with zero graduations vertical and the prism indicator on upper zero. Both prisms should then be turned simultaneously about four degrees toward the nasal side of the patient, thus tending to jointly force corresponding muscles of both eyes.
Home Treatment for Muscular Exercise—
Square Prism Set Used in Conjunction
With the Ski-Optometer
Where a patient is unable to call each day for this muscular treatment or exercise, the work will be greatly facilitated by employing a specially designed set of square prisms ranging in strength from ½ to 20 degrees for home treatment. As in the case previously cited, it is necessary to carefully instruct the patient that the interni muscles must be developed, hence prism base out with apex in must be employed. Attention should then be directed to a candle light, serving as a muscle testing spot of light and stationed in a semi-dark room at an approximate distance of twenty feet.
Having determined through the Ski-optometer the strength of the prism required after each office treatment, its equivalent should then be placed in a special square prism trial-frame which permits rotation of the prism, although the patient is frequently taught to twirl the lens before the eye. This exercise may be continued for about five minutes each day.
The patient should also be instructed to call at the end of each week, when the work may be checked by means of the Ski-optometer’s rotary prisms, making the duction test as previously explained and outlined in [Fig. 24]. It is then possible to determine whether or not satisfactory results are being obtained. Otherwise the exercise should be abandoned.
Should the second method employed in the work of muscular imbalance not prove effective, the third method requiring the use of prisms would be next in routine.