Faculty Bibliography

PURPOSE/OBJECTIVE:To investigate the structural optical coherence tomography and related microvascular flow characteristics in eyes with retinal vasculitis. METHODS:Regions involved with perivascular infiltration in eyes with retinal vasculitis, but no evidence of large vessel occlusion were evaluated with optical coherence tomography (OCT), OCT angiography, and fluorescein angiography. RESULTS:Ten eyes of 5 patients with a variety of etiologies of retinal vasculitis were evaluated. These patients did not have either cotton wool spots or deeper placoid areas of retinal ischemia. Around large vessels there was perivascular infiltration with leakage and staining seen during fluorescein angiography. Structural OCT showed slight thickening with loss of visualization of normal retinal laminations. OCT angiography showed a lack of flow signal in capillary sized vessels in the same areas. Treatment resulted in a rapid thinning of the affected areas, with the inner and middle layers of the retina becoming thinner than surrounding uninvolved areas. OCT angiography did not show a return of capillary perfusion in these regions. The thickness change in the structural OCT as shown by a heat map had a pattern mimicking the original perivascular infiltration around large retinal vessels. CONCLUSION/CONCLUSIONS:Capillary level perfusion abnormalities can develop in regions adjacent to large vessel inflammatory infiltrate that result in retinal thinning without the development of usual stigmata of acute microvascular flow obstruction such as cotton wool spots. This suggests that retinal damage may occur in retinal vasculitis that would not be recognized without using OCT-based imaging modalities.

PURPOSE/OBJECTIVE:To summarize the results of 2 consensus meetings (Classification of Atrophy Meeting [CAM]) on conventional and advanced imaging modalities used to detect and quantify atrophy due to late-stage non-neovascular and neovascular age-related macular degeneration (AMD) and to provide recommendations on the use of these modalities in natural history studies and interventional clinical trials. DESIGN/METHODS:Systematic debate on the relevance of distinct imaging modalities held in 2 consensus meetings. PARTICIPANTS/METHODS:A panel of retina specialists. METHODS:During the CAM, a consortium of international experts evaluated the advantages and disadvantages of various imaging modalities on the basis of the collective analysis of a large series of clinical cases. A systematic discussion on the role of each modality in future studies in non-neovascular and neovascular AMD was held. MAIN OUTCOME MEASURES/METHODS:Advantages and disadvantages of current retinal imaging technologies and recommendations for their use in advanced AMD trials. RESULTS:Imaging protocols to detect, quantify, and monitor progression of atrophy should include color fundus photography (CFP), confocal fundus autofluorescence (FAF), confocal near-infrared reflectance (NIR), and high-resolution optical coherence tomography volume scans. These images should be acquired at regular intervals throughout the study. In studies of non-neovascular AMD (without evident signs of active or regressed neovascularization [NV] at baseline), CFP may be sufficient at baseline and end-of-study visit. Fluorescein angiography (FA) may become necessary to evaluate for NV at any visit during the study. Indocyanine-green angiography (ICG-A) may be considered at baseline under certain conditions. For studies in patients with neovascular AMD, increased need for visualization of the vasculature must be taken into account. Accordingly, these studies should include FA (recommended at baseline and selected follow-up visits) and ICG-A under certain conditions. CONCLUSIONS:A multimodal imaging approach is recommended in clinical studies for the optimal detection and measurement of atrophy and its associated features. Specific validation studies will be necessary to determine the best combination of imaging modalities, and these recommendations will need to be updated as new imaging technologies become available in the future.

Importance/UNASSIGNED:Correct attribution of vascular features in optical coherence tomography (OCT) angiography depends on accurate segmentation of retinal layers. Objective/UNASSIGNED:To evaluate the segmentation of retinal layers among 3 OCT angiography instruments in the central macula, an area where the superficial and deep vascular plexuses terminate. Design, Setting, and Participants/UNASSIGNED:A retrospective review of a representative OCT angiogram from 1 patient and an evaluation of the vascular pattern in an autopsied eye were conducted at a community retina practice at a university laboratory. A set of 3 × 3-mm scans centered on the fovea using the Cirrus 5000, RTVue XR Avanti, and Triton DRI OCT platforms with default layer segmentations were used to evaluate segmentation accuracy of a normal macula of a white man in his 60s as an emblematic example. A representative histologic section from the central macula of a normal eye was used as an exemplar. Main Outcomes and Measures/UNASSIGNED:Retinal layer segmentation and resultant vascular image compared with vessels as seen in histologic section. Results/UNASSIGNED:The segmentation slab designed to isolate the superficial vascular plexus included the deep vascular plexus in the central macula for all 3 instruments. None of the instruments produced segmented regions that followed the relevant anatomic layers correctly. Conclusions and Relevance/UNASSIGNED:Because of inherent errors in segmentation, studies of the superficial and deep vascular plexuses using manufacturer-recommended default settings are likely to be biased. A proposal for an improved segmentation strategy is presented.

PURPOSE/OBJECTIVE:To visualize choroidal blood flow in larger vessels in highly myopic eyes using a phenomenon of the projection artifact to in the sclera using optical coherence tomography angiography. METHODS:The retrospective study included 92 eyes (54 patients) with greater than 8 diopters of myopia. All eyes were examined using optical coherence tomography angiography (RTVue XR Avanti; Optovue Inc, Fremont, CA). The blood flow in choroidal vessels was evaluated by attempting to directly segment the choroid and also by placing the segmentation layer behind the choroid, within the sclera. Subfoveal choroidal thickness was also measured at the same time. The authors also evaluated the 54 normal eyes (54 cases) without high myopia as a control group. RESULTS:Segmentation artifacts occurred in 68 cases (73.9%) and precluded direct visualization of the choroidal blood flow in larger vessels. When the segmentation slab was placed posterior to the choroid within the sclera, the choroidal blood flow was visualized in 41 eyes (44.6%). The mean subfoveal choroidal thickness in eyes with visualization of choroidal blood flow was thinner than without visualization (50.3 ± 42.2 μm vs. 100.3 ± 44.4 μm, P < 0.01). Choroidal blood flow in larger vessels was imaged in no control eye. CONCLUSION/CONCLUSIONS:The choroidal vessel anatomy could be imaged by detecting flow using the projection artifact in the sclera with optical coherence tomography angiography. This technique may be useful in estimating the vascularity of the choroid.

PURPOSE/OBJECTIVE:To evaluate multimodal imaging including volume-rendered angiographic and structural optical coherence tomography of macular telangiectasia Type 2 (MacTel2) for right-angle vein complexes, macular cavitations, and signs of deeper retinal vascular invasion. METHODS:Retrospective review of imaging performed in a community-based retinal referral center. The eyes were scanned using optical coherence tomography using split-spectrum amplitude-decorrelation techniques to derive flow information. These data were extracted and used to create volume-rendered images of the retinal vasculature with integrated structural information derived from the component optical coherence tomographic images. RESULTS:There were 24 eyes of 16 patients who had a mean age of 61.8 years. Right-angle veins seemed in association with vascular proliferation external to the deep vascular plexus. The origin of a right-angle vein was surrounded by a stellate arrangement of radiating retinal vessels apparently caused by contraction of surrounding tissue in the temporal macula. Cavitations were found in the fovea and varied in size and configuration from one examination to the next. Many smaller cavitations, called microcavitations, were seen in the surrounding macula. Vascular invasion occurred into the subretinal space. CONCLUSION/CONCLUSIONS:There are contractile features of the tissue in the temporal macula and the number, size, and temporal variations in the cavitations have not been in not mentioned in previous published descriptions of MacTel2. Vascular invasion of deeper layers occurred in the temporal macula through the outer nuclear layer. Volume-rendered angiographic and structural optical coherence tomography offers unprecedented ability to examine the vascular interrelationships their associations with cavitations in the macula.