Faculty Bibliography

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/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/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.

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: 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.

A 20-year-old white woman presented with bilateral acute visual loss (visual acuity: 20/60), panuveitis, and exudative retinal detachments 3 weeks after a second dose of quadrivalent human papillomavirus (HPV4) vaccine. She was treated with oral prednisolone for 6 weeks and responded rapidly. By week 4, vision had normalized and clinical signs resolved. Uveitis after HPV4 vaccination has been reported in two cases. Although the differential diagnosis includes Harada disease, temporal correlation with HPV4 and definitive response to a short course of treatment implicate the vaccine in this case. Vaccine-induced uveitis is rare and difficult to distinguish from coincidental autoimmune disease. [Ophthalmic Surg Lasers Imaging Retina. 2015;46:967-970.].

PURPOSE: To investigate the interactions among drusen type and multimodal vision testing in eyes with nonexudative age-related macular degeneration. METHODS: Fifty-one eyes of 39 patients with nonexudative age-related macular degeneration underwent fundus imaging including spectral domain optical coherence tomography, color fundus photograph, and autofluorescence imaging, each of which was graded by 2 masked readers. Multimodal vision testing included visual acuity using the Early Treatment Diabetic Retinopathy Study protocol refraction, contrast sensitivity, and microperimetry. RESULTS: Generalized estimating equation modeling showed that the significant predictors of contrast sensitivity was the presence of pseudodrusen (P = 0.012) and refractive error (P = 0.028). The presence of pseudodrusen inversely correlated with contrast sensitivity. The significant predictors of parafoveal microperimetry score were area of confluent hypoautofluorescence (P = 0.026) and the presence of pseudodrusen (P = 0.027). Both of them showed an inverse correlation with microperimetry score. The only significant predictor of macular microperimetry score was the presence of pseudodrusen (P = 0.004), which showed an inverse correlation with microperimetry score. CONCLUSION: The analysis of predictors of the visual function highlights the importance of pseudodrusen. Pseudodrusen are not only the risk factor of late age-related macular degeneration but also affect visual function. Recognition of this problem is important for low-vision rehabilitation and therapeutic strategies for late age-related macular degeneration.