Comparison of the cardiovascular effects of 2.5% phenylephrine and 10% phenylephrine during ophthalmic surgery

Purpose The recommended concentration of topical phenylephrine for mydriasi s is still a matter of debate. Our purpose was to compare the cardiovascula r effects of 10% and 2.5% topical aqueous phenylephrine. Methods We carried out a double-masked randomised study on 54 consecutive p atients undergoing routine local anaesthetic cataract extraction, comparing the effects on blood pressure and heart rate of either 2.5% or 10% topical aqueous phenylephrine in combination with 1% topical aqueous tropicamide i n those with no history of cardiovascular disease. Results No difference was found in the rise in blood pressure produced by 2 .5% and 10% topical aqueous phenylephrine. We also found no sustained chang es in blood pressure or heart rate after instillation of either 2.5% or 10% topical aqueous phenylephrine. Conclusion We recommend the routine use of 2.5% topical aqueous phenylephri ne as a mydriatic agent during cataract surgery and acknowledge the role of 10% topical aqueous phenylephrine as an effective mydriatic agent in cases where 2.5% phenylephrine may not be so effective, such as in subjects with darkly pigmented irides.