Cataract extraction / by H. Herbert.

  • Herbert, H.
Date:
1908
Catalogue details

Licence: In copyright

Credit: Cataract extraction / by H. Herbert. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    allow of very rapid removal of the instrument when in use. Landolt's models—one nasal, one temporal—are fixed by a small lever and rack, worked by simple pressure of the finger. The arms of Mellinger's and Roster's ingenious instruments, working by rack mechanism, can be approximated at once for withdrawal by simple pressure between the finger and thumb of one hand ; yet they effectually resist pressure exerted by the lid muscle. They are said, however, to produce too wide a separation of the lids in some cases. Other patterns provide for easy removal, but do not control the lids so well. Miiller's Fig. 13.—Gaupillat's Speculum. instrument closes and falls away automatically on powerful contraction of the orbicularis. Some specula are fitted with solid curved end-plates to cover the lashes and lid-borders, either fixed, as in Lang's modification of Clark's speculum, or movable, as in Terson's and Gaupillat's models. In one of Lang's modifications there is a guard for overhanging upper lid. Other specula have simple bars as guards for the lashes. The benefit of such coverings is seen mainly in using a keratome for an upper section, in performing simple iridectomy or a linear extraction. It is scarcely appre- ciable in an ordinary flap extraction. In Landolt's instrument only two hooks pass behind the border of each lid, the bar connecting them lying in front of the lid;
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