OSLI Retina

December 2016

Issue link: http://osliretina.healio.com/i/761988

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1142 Ophthalmic Surgery, Lasers & Imaging Retina | Healio.com/OSLIRetina In a highly pigmented iris, OCTA only shows up in the surface vessels, as the deeper ones may be masked by pigment. Furthermore, 6 × 6 volume cubes images show clearly the conjunctival vascular network. DISCUSSION Early studies with iris fluorescein angiography (FA) aimed mainly at establishing the patterns of the normal iris, giving information about either the iris vasculature or, indirectly, the retinal circulation. This may be useful when visualization of the retina is difficult because of opacities of the optic media, or to detect new vessels of the iris. It was interesting to obtain the same results using a technique without contrast dye; hence, no risk. OCTA is promising for examining the central retina, and we employed it to study the iris vascularization. OCTA machines are actually set for retinal examination, but with some adjustments it is also possible to visualize the iris. This can be done with our instrument, employing the same programs and only making manual adjustments using the anterior segment adaptor (Figures 1 and 2). The vascular network is less clearly visible in a highly pigmented iris. Even in these cases, however, OCTA can give useful information. If the eye presents neovascularization, this will produce some alterations to vascular markings that can be assessed, as they will normally become evident at the surface. Unlike with FA, it is not possible to assess vascular leakage with OCTA; it is only possible to assess the presence of neovascularization or a reduction in vascular markings. However, the method does provide information on the retinal circulation in situations where this cannot be explored, and on the presence of iris neovascularization, without any dye injection. REFERENCES 1. Jensen VA, Lundbaek K. Fluorescence angiography of the iris in recent and long-term diabetes. Diabetologia. 1968;4(3):161-163. 2. Kwiterovich KA, Maguire MG, Murphy RP, et al. Frequency of ad- verse systemic reactions after fluorescein angiography. Results of a prospective study. Ophthalmology. 1991;98(7):1139-1142. 3. Spaide RF, Klancnik JM Jr., Cooney MJ. Retinal vascular layers im- aged by fluorescein angiography and optical coherence tomography angiography. JAMA Ophthalmol. 2015;133(1):45-50. 4. Ang M, Sim DA, Keane PA, et al. Optical coherence tomography an- giography for anterior segment vasculature imaging. Ophthalmology. 2015;122(9):1740-1747.

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