Causes.—The inequality of power in the two eyes has been regarded by many as a cause of strabismus; the defective eye, it is said, " in stead of being fixed on the object before it, is left to wander from the true axis of vision." When, however, we consider how numerous are the examples of unequal vision with the two eyes, yet unattended with squint, and the great and immediate improvement of sight which generally results from the operation for the removal of the defect, we may fairly question the influence of this cause in the production of strabismus. Among the remote causes which unquestionably con tribute to this effect, may be enumerated convulsions, teething, the irritation arising from worms, ophthalmia, imitation, a habit of mis directing the eyes, as by frequently looking at a mole on the nose, &c. The proximate cause resides in some affection of the muscles or nerves of the eyeball; either the balance of power between the former is lost, or the sympathy which exists naturally between the motor-oculi nerves of the two eyes is impaired.
Treatment.—This must depend upon whether the affection is of a temporary or permanent nature ; in the former case it will be found to arise from some local irritation, and can be removed by suitable therapeutic remedies; in the latter, au operation will generally be required. Among the different other plans of treatment which occa
sionally have proved successful, wo may enumerate binding up the sound eye; the employment of spectacles having glasses of different power ; blinders projecting in front of the temples, with a view of attracting the eyes outwards; electricity, &c. The operation for the cure of strabismus is said to have suggested itself first to Dr. Stromeyer, from witnessing the success of tenotomy in contractions of the limbs. Dr. Dieffenbaeh of Berlin, however, was the first who had the boldness to carry it into practice on the living subject. The operation consists in dividing the muscle by which the distortion is produced, and thus allowing its antagonist to draw the eye again into the centre of the orbit. Although most cases of strabismus may be either completely cured or very much bettered by this operation, it is proper to remark that iu some, neither this nor any other plan of treatment is of any avail. Provided, however, that the subjects to be operated ou are judiciously selected, and the surgeon qualified for the task, there is no operation within the whole range of surgery which is more simple, more free from danger, or more satisfactory in its results, than the one in question.