The effect of topical instillation of 2.5% phenylephrine and 1.0% tropicamide on the blood pressure of hypertensive patients

Background: Pupillary dilation is necessary to complete a thorough examination of the internal ocular structures and perform threshold visual fields on the automated perimeter. In our clinic, the topical instillation of 2.5% phenylephrine and 1.0% tropicamide following one drop of topical anesthetic is used routinely for pupil dilation. The vasoconstrictive effects of phenylephrine can cause an increase in peripheral resistance resulting in elevation of systolic and diastolic blood pressures. A rise in systemic blood pressure has been shown to occur following topical instillation of phenylephrine (Heath, Arch Ophthalmol, 1936;16:839–846). This study investigates the effect of topical instillation of 2.5% phenylephrine and 1.0% tropicamide on the blood pressure of known hypertensive patients 30 and 70 min after instillation. Methods: 118 hypertensive patients, all of whom were being treated with anti-hypertensive medications, were involved in the study. Fifty-six patients were dilated with two drops 2.5% phenylephrine and two drops 1.0% tropicamide instilled 5 min apart after one drop of local anesthetic (proparacaine 0.5%). The remaining 62 patients were examined but not dilated. Blood pressure was measured using a sphygmomanometer and stethoscope (right arm sitting) prior to dilation and 30 and 70 min following drop instillation. Results: No clinically significant increase in blood pressure at 30 and 70 min after instillation was observed in the hypertensive group that was dilated. In addition, the change in blood pressure of the dilated group and undilated group was not statistically significant. Conclusion: This study shows that pupillary dilation with 2.5% phenylephrine and 1.0% tropicamide did not significantly increase systemic blood pressure in this population of hypertensive patients.