Are foveal avascular zone and macular vessel parameters different, pre and post dilatation in diabetes?

Introduction Optical coherence tomography and optical coherence tomography angiography are ancillary tests done in an ophthalmological examination to observe the structural and functional state of retinal vasculature. Diabetes mellitus affects these vessels, and tests are often done in the dilated eye for precise images. The effect of mydriatic drops, which are used for this purpose, on the macular vasculature of retinopathic eyes has not been evaluated, and an existing change could alter the pathological assessment of macular vasculature. Material and methods We evaluated the effect of dilating drugs on vessel density, perfusion, and foveal avascular zone, which may reflect an altered vascular picture, and thus a deviation from the non-dilated vascular status of the macula. We assessed 60 eyes in our cross-sectional study as per Inclusion and exclusion criteria, (diabetics with retinopathy, without retinopathy, and non-diabetics). Optical coherence tomography and optical coherence tomography angiography were performed in all eyes before and after mydriasis. The pre- and post-mydriatic values for each macular zones were analysed. Results The centre, inner, and full zones of the macula of diabetics with and without retinopathy and the controls were analysed for vessel density and perfusion. The Wilcoxon signed rank test was employed. Significant changes in VD and VP were noticed after dilatation with retinopathy. The macular vasculature of non-diabetics and diabetics without retinopathy, except for the central zone, remained unchanged. Foveal avascular zone remained insignificant. Conclusions This study discloses the effect of mydriatic drops on vessel density and perfusion of macular vessels among diabetics. To delineate the true vascular status of the macula of an eye with retinopathy, optical coherence tomography angiography in an undilated eye would be desirable.