A handbook of local therapeutics / edited by Harrison Allen.

Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: A handbook of local therapeutics / edited by Harrison Allen. Source: Wellcome Collection.

    216/554 (page 204)
    opacity in tl,e form of striped keratitis. In relation to the latter the quest.on has been raised whether the opacity was the direct effei of coca,ne, or was rather induced by other applications made at thet ° .me, parttcularly of bichloride of mercury, whose action on the deeTe layers of the cornea was facilitated by the increased absorption, whic one of the results of cocainization. Wiirdinger (Frost liL) fo„„d that solutions of borax, boric acid, corrosive sublimate, and even of common salt, produced the same kind of turbidity in the cocainized cornea. ^ni^cu M.ttendorf {Am. Ophihal. Soc, 1888) reports three cases in which cocaine caused Acute Conjunctivitis, with tense, swollen lids, and profuse muco-purulent discharge, similar to that occasionally met with as an effect of atropine. This must be attributed to a very rare idiosyn- crasy, but the tendency to subsequent hyper^emia necessitates caution in prescribing cocaine for continuous use, particularly in strong solutions Cocaine has been accused of inducing panophthalmitis after cataract extraction, but the reports of cases on which this charge is based are few and do not rigidly exclude other possible causes. Cocaine is a convenient and safe mydriatic for ophthalmoscopic pur- poses. As It only slightly impairs the accommodation, and its effect on the pupil passes off in a few hours, it can often be used when other mydriatics are inadmissible. It is easy to neutralize its effects by eserine, and it is well to do so when there is any suspicion of a tendency to glaucoma. According to Jackson, its effect on the pupil is neutralized by one-fiftieth of its weight of eserine, while Jessop's estimate is one- twenty-sixth. It is probably not possible to strike an exact balance, but, practically, a solution of half a grain to the ounce of eserine may be depended upon to obviate any inconvenience from the use of the four per cent, solution of cocaine. Therapeutically, the value of cocaine as an anodyne is limited by the transient character of its action and the inconveniences and even dan- gers that may result from its too frequent or long-continued use. In small proportions (one or two grains to the ounce) it maybe conveniently and safely added to astringent or antiseptic washes to modify their irri- tating effects, and full anaesthesia greatly facilitates the application of caustics or the use of the actual cautery. It is frequently combined with atropine in the treatment of Iritis, not only for its anodyne effect, but because it assists in dilating the pupil both by its own action upon the iris and by increasing the absorbing power of the cornea. Cocaine, however, finds its widest field of usefulness in operative ophthalmic surgery. The ansesthesia produced by it in the conjunctiva and cornea is complete, and any operation involving these tissues only is rendered absolutely painless. It is almost universally used in extraction