Abstract
Purpose:
To investigate the effect of common dilating eye drops used for eye examination on systemic blood pressure (BP) in adults, and how this may interact with history of hypertension and associated medication use. The formulations examined, tropicamide 1% (T) and tropicamide 1% & phenylephrine 2.5% (T+P), are used in eye care settings the world over yet their systemic effects are not well documented.
Methods:
In this prospective randomized study, patients received a single dose of either T or T+P. Immediately prior to instillation of drops, an automated cuff obtained baseline BP and pupil size was measured by slit lamp exam. A second reading was obtained 30 minutes after drops were given. Direct patient questioning and chart review were used to gather medication and medical history data.
Results:
104 patients were included. Mean age was 52.89±15.15 (mean±SD) years, 59.6% of patients were females, 18.3% Caucasian, 43.3% African American, 25%% Hispanic, 3.8% Asian. For the first analysis, patients were divided into two groups based on the dilating agent they received: T, or T+P. Overall, average BP did not change from baseline; mean arterial pressure (MAP) before dilation was 96.62±13.3mmHg and 96.8±12.67mmHg after dilation (p =0.8). Those receiving T+P exhibited greater pupillary dilatation than T alone, (3.67 mm vs. 4.26mm, p=0.02). This is attributable only to treatment effect, since baseline pupil sizes did not differ between T and T+P groups (p=0.9), yet pupil sizes 30 minutes after drop instillation were greater for T+P (6.91mm±1.19mm) than for T alone (6.33mm±0.93mm) (p=0.009). Next, patients were divided into those diagnosed with hypertension (HTN) and those without history of HTN (non-HTN). 93.7% of patients with HTN were on antihypertensive medications at the time of visit. Changes from baseline in MAP, systolic BP, diastolic BP, heart rate, and pupil size were compared between HTN and non-HTN groups. HTN patients’ pupils dilated to a greater extent in response to T+P (+4.09±0.98mm) than T alone (+3.35mm±0.98mm) (p=0.03). No other significant changes from baseline in the above parameters were found between HTN and non-HTN groups.
Conclusions:
Dilating eye drops containing T+P exert a stronger mydriatic effect than T alone, especially in hypertensive patients undergoing antihypertensive therapy. Neither formulation appears to affect systemic blood pressure or heart rate.
Keywords: 421 anterior segment •
571 iris •
465 clinical (human) or epidemiologic studies: systems/equipment/techniques