IMPACT OF PUPIL DILATION ON RETINAL MICROVASCULATURE IN HEALTHY EYES USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

Abstract

Purpose : To investigate the effect of pupil dilation using phenylephrine and tropicamide on quantitative assessment of retinal microvasculature using OCT-A.

Methods : This experimental design study included 27 eyes from 27 healthy participants (age range: 20-67 years). Optovue AngioVue OCT-A optic disc (4.5mm by 4.5 mm) and macula scans (3x3mm and 6 x 6 mm) were obtained at 15-minute intervals: 2 baseline sessions prior to dilation, and 2 scanning sessions after dilation. Superficial macular vessel density was measured in the whole image (mwiVD) and the parafoveal region (pfVD). Optic nerve head vessel density in the retinal never fiber layer was measured in whole image (ONH wiVD) and the circumpapillary region (cpVD) with and without automated removal of large vessels (wiVD capillary and cpVD capillary). Differences between pre and post-dilation sessions were investigated using paired t-tests.

Results : The mean ONH vessel density values ranged from 32.9% to 65.4%, the mean macula vessel density values ranged from 38.3% to 59.2%. ONH wiVD differences between the absolute value of the pre and post-dilation differences and the absolute value of pre-dilation differences was weakly significant (0.4% (0.0 to 0.8, p<0.048)). The absolute value of the differences between other ONH pre and post-dilation measures, wiVD capillary (0.3%), cpVD (0.1%), and cpVD capillary (.2%) were not statistically significant. The absolute value of the macula scan pre and post-dilation differences for mwiVD and pfvd from the 3x3 mm scan (0.6% and 0.6%, respectively) and the 6x6 mm scan (0.6% and 0.8%, respectively) were not statistically significant.

Conclusions : With the exception of absolute difference between pre and post-dilation ONH wiVD OCT-A vascular measurements being weakly significant, there were no other disc and retinal vasculature significant differences between pre and post-dilation. These results suggest that in healthy eyes, differences between pre and post-dilation vessel density measurements are interchangeable.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.