Faculty Bibliography

PURPOSE/OBJECTIVE:To determine frequency and associations of macular Bruch membrane defects in the region of macular atrophy developing after the onset of myopic choroidal neovascularization (CNV). DESIGN/METHODS:Retrospective observational case series. METHODS:The study included all patients who were consecutively examined for high myopia (axial length ≥26.5mm) and CNV-related macular atrophy in the study period from June to July 2015. The patients underwent a comprehensive ophthalmologic examination including swept-source optical coherence tomography (OCT) of the macula. Main outcome measures were macular Bruch membrane defects. RESULTS:Out of 33 eyes (28 patients) with myopic CNV-related macular atrophy, 25 eyes (76%) showed macular Bruch membrane defects, which were characterized by a lack of Bruch membrane, retinal pigment epithelium, photoreceptors, and choriocapillaris. At the edges of the macular Bruch membrane defects, the ends of the Bruch membrane were upturned, and an inward protrusion of large choroidal vessels could be detected. In the center of macular Bruch membrane defects, remnants of Bruch membrane could be crumpled. In multivariate analysis, higher prevalence of secondary macular Bruch membrane defects was significantly associated with a lower prevalence of intravitreal medical therapy (P < .001) after adjusting for larger macular atrophy area size (P < .001) and longer interval between development of the CNV and final examination (P = .42). CONCLUSIONS:Macular Bruch membrane defects belong to the hallmarks of myopic CNV-related macular atrophy. Since macular Bruch membrane defects lack photoreceptors and thus represent psychophysically an absolute scotoma, they are of profound importance for visual prognosis. As incidentally observed at study end, the prevalence of macular Bruch membrane defects may be lower if a previous myopic CNV was treated by intravitreal medical therapy.

PURPOSE: Macular pigments are preferentially concentrated in the central fovea, an area devoid of vasculature. We hypothesized that there may be a link between the macular pigment profile and the size and structural characteristics of the foveal avascular zone (FAZ). METHODS: Two-wavelength autofluorescence method was used to quantify macular pigment optical density (MPOD) and the radius at half peak of MPOD, which was defined as the retinal eccentricity where the MPOD value was 50% of the peak value. Volumetric spectral-domain optical coherence tomography (OCT) images of the macula were obtained from 32 subjects. The equivalent radius of the FAZ was determined using data generated from OCT angiography. Generalized estimating equations were used to test the hypothesis that there are interrelationships among the central foveal thickness, peak MPOD, the radius at half peak of MPOD and the equivalent radius of the FAZ. RESULTS: The equivalent radius of the FAZ was highly correlated with the radius at half peak of MPOD (P < .001). The equivalent radius of the FAZ was a significant predictor for central foveal thickness (P < .001). The significant predictor for peak MPOD was central foveal thickness (P = .004). Eyes with larger FAZs were more likely to have a secondary peak in their MPOD spatial profile in a zone ranging from 0.5 to 1.0 degrees from the foveal center. CONCLUSIONS: The spatial distribution of macular pigment is related to the size of the FAZ, in addition to the central foveal thickness. It is possible that xanthophyll pigment accumulation in the macula serves functions, such as attenuation of shorter wavelengths of light, that would have been provided by the light-filtering characteristics of blood vessels.

PURPOSE: To evaluate potential accumulation of fluid in the outer choroid in eyes with central serous chorioretinopathy. DESIGN: Retrospective observational case series. METHODS: Patients in two community-based retinal practices were evaluated for hyporeflective areas in the outer choroid consistent with collections of fluid using enhanced depth imaging optical coherence tomography. Eligible patients were examined over the preceding 2 years, had a history of central serous chorioretinopathy, and did not have a history of choroidal neovascularization or photodynamic therapy. RESULTS: In the New York group there were 131 eyes of 70 patients who had a mean age of 56.3 (+/- 12.5) years, and 88 (67.2%) had hyporeflective regions consistent with posterior loculation of fluid in the macular region. In the Minnesota data set there were 91 eyes of 48 patients who had a mean age of 47.9 (+/-9.9) years and hyporeflective regions consistent with posterior loculation of fluid was present in 59 (64.8%). In the entire group the mean subfoveal choroidal thickness of those without loculated fluid was 344 microns as compared with 498 microns with loculated fluid (P<.001). The areas of loculated fluid were hyporeflective, were larger topographically than the large choroidal vessels, had an angular inner border, and did not have a bounding vascular wall. CONCLUSIONS: Posterior loculation of fluid is a common finding in central serous chorioretinopathy, but it has a different pattern and distribution than does collections of fluid in the outer choroid and suprachoroidal space as seen in other forms of choroidal effusion.

PURPOSE/OBJECTIVE:To investigate the retinal vascular findings and associated anatomic abnormalities in the central macula of eyes with diabetic retinopathy using volume-rendered angiographic and structural optical coherence tomography. STUDY DESIGN/METHODS:Observational case series. METHODS:In this retrospective study 25 eyes of 14 consecutive patients were imaged with optical coherence tomography (OCT) using split-spectrum amplitude decorrelation. The structural OCT data were segmented for cystoid spaces and integrated into the angiographic data for subsequent volume rendering. The opacity of various vascular layers could be decreased to improve visualization of deeper structures and the images could be rotated about 3 axes. The inner and deep vascular plexus were analyzed in relation to structural changes such as cystoid spaces and disorganization of the retinal inner layers. RESULTS:Retinal vascular flow abnormalities manifested by large flow voids in the inner vascular layer with retention of large vessels and confluent areas of flow loss in the deep plexus. Areas of cystoid edema were associated with topographically colocalizing flow voids in the deep vascular layer. In eyes with no edema isolated abnormalities of the deep plexus were associated with thinning of the inner nuclear layer and abnormalities of both layers were associated uniformly with the OCT findings of disorganization of the retinal inner layers. CONCLUSIONS:Widespread vascular abnormalities in diabetic retinopathy could be delineated along with the corresponding anatomic changes in the retina using volume-rendered angiographic and structural OCT. This method of imaging offers potential to improve visualization of vascular disorders of the eye.

PURPOSE: To evaluate the vascular structure of eyes with macular telangiectasia type 2 (MacTel2) using volume-rendered optical coherence tomography angiography (OCTA). DESIGN: Retrospective cross-sectional study. PARTICIPANTS: A total of 14 consecutive patients (20 eyes) with MacTel2 who had a signal strength score >/=55 and could maintain fixation during the scan process. METHODS: The eyes were scanned using optical coherence tomography with split-spectrum amplitude decorrelation techniques to derive flow information. Data were extracted and used to create volume-rendered images of the retinal vasculature that could be rotated about 3 different axes for evaluation. MAIN OUTCOME MEASURES: Descriptive appraisal of the vascular abnormalities associated with MacTel2. RESULTS: Vessels posterior to the outer boundary of the deep retinal plexus were secondary to retinal thinning, vascular invasion, or a combination of both. These vessels had the same shape and distribution as the late staining seen during conventional fluorescein angiography. Lateral contraction in the temporal macula in 5 eyes created an appearance of vessels radiating from a central locus, which was the site of a right angle vein. Loss of macular tissue as part of the disease process led to a central amalgamation of the inner vascular plexus and the deep vascular plexus, which appeared to be in a state of decline. Subretinal neovascularization originated from the retinal circulation but involved not only the subretinal space but also could infiltrate the remaining, thinned, retina. CONCLUSIONS: Volume rendering of OCTA information preserves the 3-dimensional relationships among retinal vascular layers and provides opportunities to visualize retinal vascular abnormalities in unprecedented detail. The retinal vascular leakage and invasion in MacTel2 may arise as a consequence of loss of control with depletion of Muller cells and exposure of the remaining retinal vessels to the more hypoxic environment near the inner segments of the photoreceptors.

PURPOSE: To use volume-rendered optical coherence tomography angiography to investigate vascular proliferation in macular telangiectasia type 2 (MacTel2), extending beyond the retinal pigment epithelium (RPE). METHODS: Six eyes of four patients with MacTel2 with neovascularization proliferating external to the RPE confines were studied. Eyes were scanned using optical coherence tomography using split-spectrum amplitude-decorrelation techniques to derive flow information (RTVue XR; Optovue). These data were extracted and used to create volume rendered images of the area of vascular proliferation. RESULTS: Mean age was 66.2 years. There was demonstrable vascular proliferation in the sub-RPE space observable by both optical coherence tomography and optical coherence tomography angiography. Fibrovascular RPE detachments were identified in all eyes. The topographic distribution of abnormal vessels located below the plane of the deep retinal vascular plexus and above the RPE closely matched the pattern of hyperfluorescence and leakage on fluorescein angiography. Vessels under the RPE demonstrated different branching patterns and larger diameter lumens than those above the RPE, but anastomosis with the choroidal circulation was difficult to demonstrate. CONCLUSION: This study provides evidence that sub-RPE vascular proliferation may be a complication of MacTel2. Retinal pigment epithelium abnormalities are known to occur in MacTel2 and may provide a conduit for abnormal vessels in the subretinal space to proliferate into the sub-RPE compartment. The authors have no reason to exclude the possibility that the choroid contributes to the deep proliferation.

PURPOSE/OBJECTIVE:To demonstrate combined and integrated volume rendering of the retinal vasculature and selected structural abnormalities information derived from optical coherence tomography. METHODS:The eyes were scanned using optical coherence tomography using split-spectrum amplitude-decorrelation techniques to derive flow information. Various sublayers could be color coded as needed. The corresponding structural optical coherence tomography information was segmented for salient anatomic structures of interest, such as areas of edema fluid or intraretinal lipid deposits. The angiographic and structural data were integrated on a plane-by-plane basis and used to create volume-rendered images. The combined volume-rendered angiographic and structural optical coherence tomography data could be rotated about three different axes for evaluation. RESULTS:Representative images from the eyes with diabetic macular edema, Type 1 macular telangiectasis, choroidal neovascularization, and retinal veno-occlusive disease are shown. The interrelationships between areas of cystoid fluid accumulation or intraretinal lipid accumulation could be visualized. CONCLUSION/CONCLUSIONS:Although structural and angiographic findings are typically shown in isolation, they can be integrated into a merged data set that is amenable to volume rendering. Using this new technique will allow investigation into the interrelationships between vascular and structural abnormalities of the retina and choroid.

PURPOSE/OBJECTIVE:To describe image artifacts of optical coherence tomography (OCT) angiography and their underlying causative mechanisms. To establish a common vocabulary for the artifacts observed. METHODS:The methods by which OCT angiography images are acquired, generated, and displayed are reviewed as are the mechanisms by which each or all of these methods can produce extraneous image information. A common set of terminology is proposed and used. RESULTS:Optical coherence tomography angiography uses motion contrast to image blood flow and thereby images the vasculature without the need for a contrast agent. Artifacts are very common and can arise from the OCT image acquisition, intrinsic characteristics of the eye, eye motion, image processing, and display strategies. Optical coherence tomography image acquisition for angiography takes more time than simple structural scans and necessitates trade-offs in flow resolution, scan quality, and speed. An important set of artifacts are projection artifacts in which images of blood vessels seem at erroneous locations. Image processing used for OCT angiography can alter vascular appearance through segmentation defects, and because of image display strategies can give false impressions of the density and location of vessels. Eye motion leads to discontinuities in displayed data. Optical coherence tomography angiography artifacts can be detected by interactive evaluation of the images. CONCLUSION/CONCLUSIONS:Image artifacts are common and can lead to incorrect interpretations of OCT angiography images. Because of the quantity of data available and the potential for artifacts, physician interaction in viewing the image data will be required, much like what happens in modern radiology practice.