J. Aggarwal, B. Beveridge
Aug 1, 1971
Citations
1
Influential Citations
23
Citations
Quality indicators
Journal
British Journal of Ophthalmology
Abstract
Phenylephrine hydrochloride is a topical mydriatic widely used in clinical practice. Its action is due to a direct sympathomimetic effect upon the myoneural junction, resulting in mydriasis, slight cycloplegia, an increase in the facility of aqueous outflow, and constriction of the conjunctival vessels. The I 0 per cent. aqueous solution is commonly used, but reaction has been observed after the instillation of solutions as weak as 0 I 25 per cent. (Havener, I 966) and o * I per cent. (Haddad, Moyer, and Riley, 1970), which is enhanced by increased absorption after trauma to the corneal epithelium. One side-effect of its action is the liberation of pigment granules into the aqueous 30 to 40 minutes after instillation, a phenomenon first described by Mitsui and Takagi (i96i), who observed that it occurred in 4-6 per cent. of subjects after the instillation of a 5 per cent. solution. The majority of these subjects were middle-aged or elderly, and it was shown that the pigment granules had the same characteristics as those in the cells of the iris neuroepithelium. Haddad and others (i970) observed similar aqueous floaters in a high proportion of subjects over the age of 50 years after the instillation of I per cent. and commercial Io per cent. solutions Biggs, Alpern, and Bennett (I 959) observed similar floaters after the subconjunctival injection of epinephrine, and Chamlin (I 959) observed them in cases of papillitis and drew attention to the diagnostic confusion which may follow the instillation of mydriatics in these cases. The present study was begun after the frequent chance observation of aqueous floaters in eyes into which Io per cent. phenylephrine hydrochloride drops had been instilled before routine fundus examination. During a period of two months, I50 patients were examined biomicroscopically both before and after dilatation of the pupils with I o per cent. phenylephrine hydrochloride solution. In forty cases (27 per cent.) an aqueous flare and floaters were observed after dilatation of the pupils; in some cases "Novesine" (Benoxinate hydrochloride 0o4 per cent.) had also been instilled.