To characterize retinal microaneurysms (MAs) in patients with diabetes using adaptive optics optical coherence tomography (AOOCT) and compare details found in AOOCT with those found in commercially available retinal imaging techniques.
Patients with diabetes and MA in the macular area were included in this pilot study. The area of interest, identified in standard fluorescein angiography, was imaged using an AO fundus camera and AOOCT. Microaneurysms were characterized in AOOCT (visibility, reflectivity, feeding/draining vessels, and intraretinal location) and compared with findings in AO fundus camera, OCT angiography, and fluorescein angiography.
Fifty-three MAs were imaged in 15 eyes of 10 patients. Feeding and/or draining vessels from both capillary plexus could be identified in 34 MAs in AOOCT images. Of 45 MAs imaged with OCT angiography, 18 (40%) were visible in the superior plexus, 12 (27%) in the deep capillary plexus, and 15 MAs (33%) could not be identified at all. Intraluminal hyperreflectivity, commonly seen in AO fundus camera, corresponded only in 8 of 27 cases (30%) to intraluminal densities seen in AOOCT.
Adaptive optics OCT imaging revealed that MAs located in the inner nuclear layer were connected to the intermediate and/or deep capillary plexus. Intraluminal hyperreflectivity seen on AO fundus camera images originated from a strong reflection from the vessel wall and only in a third of the cases from intraluminal clots. Currently, AOOCT is the most expedient in vivo imaging method to capture morphologic details of retinal microvasculature in 3D and in the context of the surrounding retinal anatomy.
Microaneurysm located in the inner nuclear layer might evolve from diving venules connecting the deep and the intermediate capillary plexus. Adaptive optics optical coherence tomography is the most expedient in vivo imaging method to capture morphologic details of retinal microvasculature in 3D and in the context of the surrounding retinal anatomy.
*Department of Ophthalmology and Optometry, Medical University Vienna, Vienna, Austria;
†Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria; and
‡Christian-Doppler-Laboratory for Ophthalmic Image Analysis (OPTIMA), Medical University Vienna, Vienna, Austria.
Reprint requests: Ursula Schmidt-Erfurth, MD, Department of Ophthalmology, Medical University Vienna, Waehringerguertel 18-20, 1090 Vienna, Austria; e-mail: firstname.lastname@example.org
Supported by European project FAMOS (FP7-ICT-217744).
W. Drexler: Carl Zeiss Meditec (C); W. Drexler and M. Pircher: Imagine Eyes (F). The remaining authors have no financial/conflicting interests to disclose.