Text-book of ophthalmology . Fig. 321.—Primary Strabismic Deviation inParalysis of the Right External Fig. 322.—Secondary Strabismic Deviation inParalysis of the Right External Rectus. secondary deviation, which therefore exceeds the primary deviation inmagnitude. It is accounted for as follows: When with both eyes uncoveredthe gaze was directed toward the right, the left internus and the rightexternus received the ordinary impulse for a movement to the right; butthe right eye lagged behind the other in proportion as the right externus,owing to its impaired innervation, failed to answ
Text-book of ophthalmology . Fig. 321.—Primary Strabismic Deviation inParalysis of the Right External Fig. 322.—Secondary Strabismic Deviation inParalysis of the Right External Rectus. secondary deviation, which therefore exceeds the primary deviation inmagnitude. It is accounted for as follows: When with both eyes uncoveredthe gaze was directed toward the right, the left internus and the rightexternus received the ordinary impulse for a movement to the right; butthe right eye lagged behind the other in proportion as the right externus,owing to its impaired innervation, failed to answer to the impulse. Ifnow the left eye is covered, the patient is compelled to make fixation withthe right. He tries now to turn this eye to the right, by sending into theright externus a very strong impulse of innervation, although in so doinghe still obtains only a very slight effect. He cannot, however, innervatethus strongly the right externus alone, but can simply send out to botheyes a very energetic impulse for a lateral movement to the right. Thisimpulse, therefore, also affects the left internus
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecteye, booksubjectophth
