Assessment of the effects of two commonly used mydriatics on the macular and peripapillary microvascular systems of healthy children: An Optical Coherence Tomography Angiography Study.

Purpose: To evaluate the effects of pupil dilation caused by topical applications of 2.5% phenylephrine and 0.5% tropicamide on retinal microvascularization using optical coherence tomography angiography (OCTA).

Methods: Healthy children were included in this prospective observational study. Baseline OCTA measurements were taken for all children before dilatation. Then they were randomly divided into two groups, the tropicamide group given 0.5% tropicamide solution and the phenylephrine group given 2.5% phenylephrine solution. After dilation OCTA images were taken for the second time from all children.

Results: The effect of dilation using two different mydriatic agents caused a decrease in mean radial peripapillary capillary density (RPC-VD) and superior RPC-VD (p=0.008 and p=0.001). Remarkably, this reduction due to dilatation was also determined to be caused by the combined effect of both mydriatic agents (p=0.016 and p=0.013). Although phenylephrine showed a slightly greater decrease than tropicamide, the effects of the two mydriatic drugs were not superior to each other (p=0.166 and p=0.167).

Conclusion: Dilation with 2.5% phenylephrine or 0.5% tropicamide significantly decreased mean RPC-VD and superior RPC-VD. Although there was no statistically significant difference between the two mydriatic agents, phenylephrine caused a greater reduction than tropicamide. This effect of dilation and phenylephrine on VD should be considered in studies using OCTA and focusing on peripapillary areas.