Atlas and epitome of operative ophthalmology . which is bentover at an angle of 90°. With such an instrument heclaims it is possible to scratch and divide the capsule inevery direction, while Gräfes cystotome permits theoperator only to cut upward and downward. WhenSnellen uses this instrument to make the ordinary crucialincision for opening the capsule, he makes a vertical incis-ion from above downward, so as not to displace thenucleus upward and thus draw it behind the wound. When there is some difficulty about opening the capsule,because the cataract is over-ripe and shrunken and thethicken
Atlas and epitome of operative ophthalmology . which is bentover at an angle of 90°. With such an instrument heclaims it is possible to scratch and divide the capsule inevery direction, while Gräfes cystotome permits theoperator only to cut upward and downward. WhenSnellen uses this instrument to make the ordinary crucialincision for opening the capsule, he makes a vertical incis-ion from above downward, so as not to displace thenucleus upward and thus draw it behind the wound. When there is some difficulty about opening the capsule,because the cataract is over-ripe and shrunken and thethickened capsule adheres with abnormal tenacity to itscontents, it is better to extract the cataract along with thecapsule, and not attempt to open the latter at all. 4. Extraction of the cataract with the capsule, a methodwhich has been chiefly developed and successfully used byA. and H. Pagenstecher, is specially adapted for over-ripecataract, which possesses an atrophic zonule of Zinn (seep. 86), so that the cataract is apt to become separated. 39 40 151 152 OPERATIONS ON THE EYE. in toto from its suspensory ligament. Atrophy of thezonule is also observed in Morgagnian cataract and incataracts that have already contracted. Dislocated andcalcified cataracts are also best removed without openingthe capsule. Ordinarily, the fact of a cataract being over-ripe isrecognized, aside from the possible presence of a capsularcataract, by the uniform gray or grayish-yellow cloudinessof the anterior cortical layer, it being impossible, evenwith oblique illumination, to make out any sharply definedmarkings. The great advantage of this method of operating isthat the entire lens is removed from the eye clean, withoutleaving any remains, while its disadvantage, which mustnot be overlooked, is that more or less vitreous is alwayslost; for such a loss is apt to occur, or at least threatensto occur, in most cases. By thorough cocainization thisaccident can, however, be confined within narrow limits
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