A COMPARATIVE-STUDY OF THE EFFICACY OF 2.5-PERCENT PHENYLEPHRINE AND 10-PERCENT PHENYLEPHRINE IN PREOPERATIVE MYDRIASIS FOR ROUTINE CATARACT-SURGERY

It is common practice in many ophthalmic units to administer multiple applications of 10% phenylephrine in combination with an anti-choliner gic agent to ensure adequate pupil mydriasis prior to routine cataract surgery. Phenylephrine is a pure alpha-1 adrenoreceptor agonist known to produce marked systemic vasoconstriction and associated hypertensi on with occasional profound reflex bradycardia. Many reviews have sugg ested caution in the use of 10% phenylephrine in the elderly or hypert ensive patient. In a prospective, randomised trial we have assessed pu pil dilation comparing the efficacy of 10% phenylephrine (53 patients) versus 2.5% phenylephrine (62 patients). When administered in conjunc tion with 1% cyclopentolate four times over 1 hour pre-operatively, 2. 5% phenylephrine was found to be as effective as 10% phenylephrine in the initiation and maintenance of mydriasis during both extracapsular and phacoemulsification cataract extraction.