The effects of phenylephrine 2.5% versus phenylephrine 10% on pupillary dilation in patients with diabetes

Purpose: A prospective, double-blind study was conducted to compare the clinical efficacy of a combination of 1% tropicamide and 2.5% phenylephrine and a combination of 1% tropicamide and 10% phenylephrine for pupillary dilation in patients with diabetes. Methods: Either 2.5% phenylephrine in one eye and 10% phenylephrine in the other eye, 2.5% phenylephrine in both eyes, or 10% phenylephrine in both eyes was administered to 127 consecutive patients with diabetes. All patients received 1% tropicamide in both eyes. Results: There was no statistically significant difference in the amount of pupillary dilation between the three groups. Conclusion: As 2.5% phenylephrine may produce a lower incidence of side effects than the 10% concentration, we advise the use of the lower concentration, particularly among patients with diabetes, who already exhibit a higher prevalence of vascular disease and autonomic dysfunction.