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Claudio Zett Lobos, Deborah M. Rosa Stina, Renata Kato, Eduardo Amorim Novais, Norma Allemann; Optical Coherence Tomography Angiography for Iris Vasculature Imaging. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3113.
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© ARVO (1962-2015); The Authors (2016-present)
To compare iris vascularization in eyes using spectral-domain (~840 nm) anterior segment optical coherence tomography angiography (AS-OCTA) and fluorescein angiography (AS-FA).
Patients with different levels of iris pigmentation were prospectively recruited to be imaged on OCTA adapted with an anterior segment lens (AngioVue, Optovue Inc., Fremont, California, USA) and confocal scanning laser ophthalmoscope (cSLO) fluorescein angiography (FA) (Spectralis HRA Heidelberg Engineering, Heidelberg, Germany) adapted with an anterior segment lens. AS-OCTA images were obtained using a 6x6 mm scan size pattern, divided into nasal and temporal quadrants and then compared to FA images.
Twenty eyes, 10 patients, with different iris colors were imaged on AS-OCTA and AS-FA. In both methods, the signal blockage was directly proportional to the intensity of the pigmentation of the iris. Considering the sample analyzed, AS-OCTA showed more details of iris vascularization than FA. Moreover, the depth-resolved characteristic of AS-OCT angiograms allowed us a 3D reconstruction of the iris. However, AS-OCTA was not able to detect contrast leaking, delay or impregnation as the AS-FA images. Patients with nystagmus and with inadequate fixation had lower quality images in OCTA compared to FA images.
AS-OCTA is a new imaging modality that allows the analysis of anterior segment and iris vascularization. In our study, AS-OCTA provided similar quality of images compared to AS-FA. In both methods, iris pigmentation equally blocked the image of iris vascularization. Additional studies including different iris pathologies are needed to evaluate the parameters of AS-OCT in anterior segment imaging.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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