Purpose: To establish a normative database for vascular density (VD) and foveal avascular zone (FAZ) at the superficial (SCP) and deep capillary plexus (DCP) in healthy subjects with optical coherence tomography (OCT) angiography. Methods: The study was a retrospective chart review of healthy patients who had undergone OCT angiography imaging. A 3- × 3-mm area, centered on the fovea, was scanned for all the study eyes. The automated segmentation allowed separate analysis of the SCP, the DCP, and a comprehensive C-scan including both vascular layers. On the obtained images, VD and FAZ measurements were computed. Interobserver reproducibility and intraobserver repeatability were also assessed. Results: A total of 135 eyes of 70 subjects (51% male) were analyzed. The mean age was 48.3 ± 17.5. We divided patients into group 1, from 20 to 39 years of age; group 2, from 40 to 59 years; and group 3, age 60 years or older. At the level of the SCP, mean VD and mean FAZ ± SD were, respectively, 52.58 ± 3.22% and 0.28 ± 0.1 mm2. At the level of the DCP, mean VD and mean FAZ were 57.87 ± 2.82% and 0.37 ± 0.12 mm2, respectively. The mean VD was significantly higher (P < 0.05) in DCP compared with SCP in all Early Treatment Diabetic Retinopathy Study (ETDRS) sectors and in all age groups. Vascular density was higher in women than in men after 60 years (P < 0.01). After adjustment on the signal strength index (SSI), the mean VD remained directly correlated with the age range and sex. The mean FAZ area was lower in group 3 (P < 0.05). Interobserver reproducibility was 0.78 to 0.99 in SCP and 0.67 to 0.92 in DCP, and intraobserver repeatability was 0.64 to 0.93 in SCP and 0.63 to 0.87 in DCP. Conclusions: Our study has provided, for the first time, age-related VD mapping data using OCT angiography in healthy subjects. The prototype software used in this study may help to improve the concept of VD grading with high inter- and intraexaminer repeatability and interexaminer reproducibility.
1 January 2016 in American Journal of Ophthalmology
Purpose: Optical coherence tomography angiography is a novel and noninvasive technique for imaging retinal microvasculature by detecting changes in reflectivity that is related to blood flow. The purpose of this study was to describe Type 2 neovascularization characteristics in age-related macular degeneration using optical coherence tomography angiography. Methods: Fourteen eyes of 14 consecutive patients with Type 2 neovascularization were prospectively included. All patients underwent a complete ophthalmological examination, including color and infrared fundus photography, fluorescein and indocyanine green angiography, spectral domain optical coherence tomography angiography, and optical coherence tomography angiography. Results: In all cases, Type 2 lesions could be detected by optical coherence tomography angiography, presenting as a hyperflow lesion in the outer retina, with a glomerulus (4/14) or medusa shape (10/14), surrounded by a dark halo. The superficial layer and the deep retina showed no abnormal flow. Surprisingly, the Type 2 lesions could also be observed in the presumed choriocapillaris layer. These glomerulus- or medusa-shaped lesions were connected, in 10/14 eyes, to a thicker main branch, which seemed to continue deep into the choroidal layers. Conclusion: Optical coherence tomography angiography may be a new imaging method for the diagnosis of Type 2 neovascularization in clinical routine. However, the specificity of the features needs to be investigated in further studies.
Purpose. To analyze optical coherence tomography angiography (OCTA) findings in eyes with central serous chorioretinopathy (CSC) and to compare them with those obtained with multimodal imaging.Methods. A series of consecutive patients diagnosed with CSC, underwent OCTA and multimodal imaging, including spectral domain OCT, fluorescein, and indocyanine green angiography. OCTA images were performed at three main depth intervals: automatically segmented outer retina, manually adjusted outer retina, and automatically segmented choriocapillaris.Results. Thirty-three eyes of 32 consecutive patients were analyzed. OCTA showed 3 main anomalies at the choriocapillaris: the presence of dark areas (19/33 eyes) which were frequently associated with serous retinal detachment, presence of dark spots (7/33 eyes) which were frequently associated with retinal pigment epithelium detachment, and presence of abnormal vessels (12/33 eyes) which were frequently, but not systematically, associated with choroidal neovascularization, as confirmed by multimodal imaging.Conclusions. OCTA revealed dark areas and dark spots, which were commonly observed. An abnormal choroidal pattern was also observed in one-third of cases, even when multimodal imaging did not evidence any choroidal neovascularization. Abnormal choroidal vessels should be interpreted with caution, and we could assume that this pathological choroidal vascular pattern observed in many CSC cases could be distinct from CNV.
Purpose: To report the imaging features of subretinal fibrosis secondary to exudative age-related macular degeneration (AMD) on optical coherence tomography angiography. Methods: All consecutive patients diagnosed with subretinal fibrosis complicating exudative AMD were imaged by color retinal photographs or multicolor imaging, fluorescein angiography, spectral domain optical coherence tomography, and optical coherence tomography angiography. Eyes with active exudative features observed during the last 6 months were compared with those without any sign of exudation >6 months. Results: Forty-nine eyes of 47 consecutive patients were included. A blood flow inside the fibrotic scar could be detected in 46 of 49 cases (93.8%). Three patterns of vascular networks could be distinguished, that were described as pruned vascular tree (26 of 49 eyes; 53.1%), tangled network (14 of 49; 28.6%), and/or vascular loop (25 of 49; 51.0%). Furthermore, 2 types of hyporeflective structures, large flow void, and/or dark halo were observed in 63% and in 65% of eyes, respectively. The observed patterns did not differ between eyes with active or inactive lesions. Conclusion: Optical coherence tomography angiography of subretinal fibrosis showed almost constantly a perfused, abnormal vascular network and collateral architectural changes in the outer retina and the choriocapillaris layer. These features were associated with both active and inactive fibrotic choroidal neovessels.