PLoS ONE (Jan 2019)

Influence of mydriasis on optical coherence tomography angiography imaging in patients with age-related macular degeneration.

  • Viktoria C Brücher,
  • Jens J Storp,
  • Laura Kerschke,
  • Pieter Nelis,
  • Nicole Eter,
  • Maged Alnawaiseh

DOI
https://doi.org/10.1371/journal.pone.0223452
Journal volume & issue
Vol. 14, no. 10
p. e0223452

Abstract

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PURPOSE:To evaluate the effect of topical mydriatic eye drops on optical coherence tomography angiography (OCTA) parameters in patients with age-related macular degeneration (AMD). METHODS:27 eyes of 27 patients suffering from AMD were included in this cross-sectional study. Patients with ≥-4.5 diopters spherical equivalent, corneal opacities or dense cataract preventing high-quality imaging were excluded. Whole-en-face scans of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in the central 3x3mm foveal region as well as whole-en-face and peripapillary scans of the radial peripapillary capillaries (RPC) were generated using OCTA (AngioVue®, Optovue). Imaging was first conducted with patients' eyes in miosis, then in mydriasis after instillation of a dilating eye drop (0.5% tropicamide, 2.5% phenylephrine-HCl). Main outcome measures were flow density (FD), foveal avascular zone (FAZ), signal strength index (SSI) and motion artifact score (MAS). RESULTS:Our results reveal that in AMD patients there is no significant difference between FD measurements taken in miosis and those taken in mydriasis around the SCP (p = 0.198), DCP (p = 0.458), RPC whole-en-face (p = 0.275) and RPC peripapillary (p = 0.503). Measurements taken in these two states appear to be equivalent for assessment of FD (90%CI within ± 0.05). No significant difference was found either in the area of the FAZ (p = 0.338) or in the SSI (p = 0.371) before and after the instillation of tropicamide/phenylephrine. MAS was significantly lower after the application of mydriatic eye drops (p = 0.003). CONCLUSIONS:Our findings reveal that neither measurements of FD nor measurements of the FAZ area changed significantly in AMD patients after the application of tropicamide/phenylephrine. Since MAS improved significantly in dilation, mydriatic examination is recommended. Nevertheless, a comparison of OCTA metrics from images taken with different pupil states (miosis versus mydriasis) is valid for clinical trials.