OSLI Retina

December 2016

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1138 Ophthalmic Surgery, Lasers & Imaging Retina | Healio.com/OSLIRetina Optical Coherence Tomography Angiography in a Normal Iris Davide Allegrini, MD; Giovanni Montesano, MD; Alfredo Pece, MD BACKGROUND AND OBJECTIVE: Optical coherence tomography angiography (OCTA) is a new imag- ing technique for examining the macular region in many retinal diseases. The aim of this study was to assess the applicability of OCTA to detect iris vascularization. PATIENTS AND METHODS: The irises of 28 eyes of 14 patients were examined with AngioVue OCT (Optovue, Fremont, CA). The usual technique was modified using the AngioRetina mode, but with the anterior segment optical adaptor lens, and with- out autofocus, while making manual adjustments. OCTA scans were captured in both eyes, always by the same operator. The images were acquired in 3 × 3 and 6 × 6 volume cubes. Raw data were then exported and split using an external tool provided by Optovue to obtain three-dimensional (3-D) iris reconstruction. RESULTS: In all eyes, OCTA showed the arterial sys- tem more superficially and the venous system more deeply in 3-D reconstruction. CONCLUSION: This is the first report of a study of the vascularization and 3-D reconstruction of the normal iris with OCTA. The method detects iris vascular network and indirectly provides informa- tion on the retinal circulation in situations where this is not visible without injecting sodium fluores- cein. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:1138-1142.] INTRODUCTION The first studies on the iris microcirculation were reported in 1968 by Jensen and Lundbaek. 1 They used the principles of retinal fluorescein an- giography (FA) to investigate the irises of diabetic patients. Compared to biomicroscopy, this proce- dure gave an objective assessment of the morphol- ogy and the vascular dynamics of anterior segment vessels. However, FA is time-consuming, invasive, and can, very occasionally, give serious adverse re- actions. 2 During the last few years, optical coherence tomography (OCT) has been largely accepted as a noninvasive instrument for the study of retinal dis- eases and the recent development of OCT angiog- raphy (OCTA) allows visualization of the capillary retinal layers and the construction of microvascular flow maps. 3 This procedure does not need injection of sodium fluorescein dye. OCTA has already been used to study the cornea and conjunctiva, 4 but it has never been used to study the iris. This paper provides the first description of the normal iris vas- culature and three-dimensional (3-D) reconstruc- tion examined with OCTA. PATIENTS AND METHODS This observational study was conducted at Retina 3000 Foundation, Milan, Italy, from September 1, 2015, to January 31, 2016. It satisfied all the requirements of the Declaration of Helsinki and Italian national laws for the protection of personal data; study participants gave signed informed consent. The local ethics committee ruled that no formal ethics approval was required in this particular case. From the Department of Ophthalmology, Melegnano Hospital, Milan, Italy (DA, AP); and the Eye Clinic, San Paolo Hospital, University of Milan, Milan, Italy (GM). Originally submitted May 28, 2016. Revision received September 3, 2016. Accepted for publication September 16, 2016. The authors report no relevant financial disclosures. Address correspondence to Davide Allegrini, MD, Department of Ophthalmology, Melegnano Hospital, Via Pandina 1, 20077 Vizzolo Predabissi, Milan, Italy; email: davideallegrini@yahoo.it. doi: 10.3928/23258160-20161130-08 ■ T E C H N I Q U E ■

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