Volume 3

The American encyclopedia and dictionary of ophthalmology / edited by Casey A. Wood, assisted by a large staff of collaborators.

Date:
1913-1921
Catalogue details

Licence: In copyright

Credit: The American encyclopedia and dictionary of ophthalmology / edited by Casey A. Wood, assisted by a large staff of collaborators. Source: Wellcome Collection.

    151/836 (page 1635)
    ders less likely orbicular spasm or deliberate “squeezing” of the lids. The handle of the knife, held as one would a pen, is elevated at an angle of 45 degrees to a tangent of the corneal curve, and a punc- ture into the anterior chamber made at the appai'ent sclero-corneal junction just above the horizontal diameter. As soon as the point of the knife has entered the anterior chamber the handle is depressed The puncture badly made. The knife point has not reached the anterior chamber but has “split” the cornea and is buried in its substance. SO that the blade may be pushed across the anterior chamber nearly parallel with the plane of the iris and towards the center of the pupil. When the pupil is reached the knife handle is again moved towards the patient’s feet and a counter-puncture made as nearly as possible at a point exactly opposite the puncture. The l ouiiter-puncture should be made at a, although in obedience to the laws of refraction, the point of the knife appears at b. Then by firm, steady and regular to-and-fro movements—pushing and pulling-—the blade cuts its way towards the upper limbus. First, the point is pushed forward and inward towards the nose, then it is pulled outward and upward towards the temple, and these motions alternated until, always following the apparent selero-comeal junc- tion, the middle of the blade reaches the uppermost sclero-corneal margin. The knife blade is then given a one-eighth turn backwards and made to cut its way out beneath the conjunctiva so as to make a small flap of the latter tissue, from 3 to 5 mm. wide and long. During the coraeal incision care should be taken that the point of the knife does not stab the lids or facial skin. Moreover, the corneal .section A-oi. m—f)