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

Abstract

PurposeTo evaluate the effect of topical mydriatic eye drops on optical coherence tomography angiography (OCTA) parameters in patients with age-related macular degeneration (AMD).Methods27 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).ResultsOur 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).ConclusionsOur 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.

Applicability of optical coherence tomography angiography (OCTA) imaging in Parkinson’s disease

“…In context of our generally quite high MAS readings, it is of interest that MAS was found to be lower during mydriatic examinations, especially in the elderly 28 . This could be at least considered when focusing on quantitative OCTA analyses in PD patients, but needs to be weighed up against the risk of accidents due to blurry vision, especially in a motorically handicapped cohort.…”

Caffeine Delays Retinal Neurovascular Coupling during Dark to Light Adaptation in Healthy Eyes Revealed by Optical Coherence Tomography Angiography

“… 5 Previous studies suggest the repeatability of OCTA without mydriasis and similar vascular parameter results with and without mydriasis. 60 , 61 In addition, although the pupillary response between the baseline and caffeine conditions may be different due to the effects of caffeine, we adjusted for the quality scores of the OCTA scans, which accounts for some of the discrepancies in light intensity or fixation that may be caused by different pupillary responses. Therefore, our results may reflect a combination of caffeine's effects on systemic blood pressure, pupillary responses, as well as its direct pharmacologic effects in the retina.…”

“…62 In addition, the repeatability (coefficient of variability = 1.2%-6.8%) of OCTA has been shown in the healthy and diseased retina, with and without mydriasis. 60,61,[63][64][65] On the other hand, OCTA measures flow-induced changes indirectly through the detection of motion contrast; and although OCTA-based flow-index has been shown in phantoms to have a linear relationship with true flow, this relationship is only valid within a limited range. 35 On OCTA, potential background motion or shadow artifacts may also interfere with angiographic signals.…”

The influence of topical cyclopentolate instillation on peripapillary and macular microvasculature measured by optical coherence tomography angiography in healthy individuals

“…It is widely used for patients of all ages in ophthalmologic practice to dilate the pupil before fundus and optic nerve examination, surgery, or fundus fluorescein angiography to create cycloplegia before the evaluation of refraction, to relieve the ciliary muscle spasm, and to decrease pain or break posterior synechia in eyes with uveitis. 4 Both retinal pigment epithelium and the choroid have been shown to contain muscarinic cholinergic receptors. 4 Both sympathomimetics and parasympatholytics have vasoconstricting effects, and they may affect the measurements of OCT-A parameters.…”

“… 4 Both retinal pigment epithelium and the choroid have been shown to contain muscarinic cholinergic receptors. 4 Both sympathomimetics and parasympatholytics have vasoconstricting effects, and they may affect the measurements of OCT-A parameters. 5 There are several studies on the influence of topical mydriatics such as tropicamide 1% and phenylephrine hydrochloride 2.5% on quantitative OCT-A parameters.…”