Faculty Bibliography

PURPOSE/OBJECTIVE:To investigate the retinal vascular findings and associated cystoid edema in the central macula of eyes with retinal vein occlusion using volume-rendered angiographic and structural optical coherence tomography. STUDY DESIGN/METHODS:Observational case series. METHODS:In this retrospective study 12 eyes of 12 consecutive patients, 3 with branch and 9 with central retinal vein occlusion, were imaged in 27 sessions 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 inner and deep vascular plexus were analyzed in relation to cystoid macular edema with retention of depth information. RESULTS:Retinal vascular flow abnormalities were demonstrated by flow voids with abnormal vascular morphology in the inner vascular layer and varying flow loss in the deep vascular plexus. Areas of cystoid edema were associated with topographically co-localizing flow voids in the deep vascular layer. Treatment with intravitreous anti-vascular endothelial growth factor injections resulted in resolution of edema but no change in flow patterns in either the inner or deep plexus. Recurrence of edema happened in the same areas of altered inner and absent deep vascular plexus flow signal. CONCLUSIONS:Cystoid macular edema in retinal vein occlusion occurred in relation to altered inner plexus and absent deep vascular plexus flow. This pattern of cystoid fluid accumulation is similar to that seen in diabetic retinopathy and may represent an important underlying pathophysiologic foundation for cystoid macular edema in retinal vascular diseases.

PURPOSE/OBJECTIVE:Patchy atrophy is a type of chorioretinal atrophy located outside of the fovea in eyes with myopic retinopathy. Bruch membrane defects have previously been described to occur in highly myopic eyes in foveal chorioretinal atrophy associated with choroidal neovascularization (CNV). We examined whether Bruch membrane defects can be found also in patchy atrophy. DESIGN/METHODS:Retrospective observational case series. METHODS:The study included all patients who were consecutively examined for high axial myopia (axial length ≥26.5 mm) and patchy atrophy in the study period from September to November 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 22 eyes (17 patients) with patchy atrophy, 21 eyes (96%) showed macular Bruch membrane defects, which were characterized by a lack of Bruch membrane, retinal pigment epithelium (RPE), photoreceptors, and choriocapillaris. At the edges of the macular Bruch membrane defects, the ends of the Bruch membrane were folded and the RPE was upturned. The inner retina overlying the area of the Bruch membrane defect was markedly thinned. CONCLUSIONS:Macular Bruch membrane defects belong to the hallmarks of a type of myopic chorioretinal atrophy not associated with CNV (ie, patchy atrophy). Considering that Bruch membrane defects were also observed in myopic CNV-related foveal atrophy, macular Bruch membrane defect might be a common finding in fundus lesions related to pathologic myopia.

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.

: Retinal vascular disease has the potential to affect hundreds of millions of people, with the inherent risk of vision loss related to cystoid macular edema. Although there have been histologic evaluation of eyes having cystoid macular edema, the most recent paper was published more than 30 years ago. In retinal vascular cystoid macular edema fluorescein angiography, a modality that images the superficial vascular plexus, shows increased leakage. Optical coherence tomography angiography has provided unprecedented resolution of retinal vascular flow in a depth resolved manner and demonstrates areas of decreased or absent flow in the deep vascular plexus colocalizing with the cystoid spaces. There has been a large amount of research on fluid management and edema in the brain, much of which may have analogues in the eye. Interstitial flow of fluid as managed by Müller cells may occur in the retina, comparable in some ways to the bulk flow in brain parenchyma, which is managed by astrocytes. Absent blood flow in the deep retinal plexus may restrict fluid management strategies in the retina, to include transport of excess fluid out of the retina into the blood by Müller cells. Application of this theory may help in increasing understanding of the pathophysiology of retinal vascular cystoid macular edema and may lead to new therapeutic approaches.

PURPOSE/OBJECTIVE:To investigate flow characteristics of the choriocapillaris using optical coherence tomography angiography. DESIGN/METHODS:Retrospective observational case series. METHODS:Visualization of flow in individual choriocapillary vessels is below the current resolution limit of optical coherence tomography angiography instruments, but areas of absent flow signal, called flow voids, are resolvable. The central macula was imaged with the Optovue RTVue XR Avanti using a 10-μm slab thickness in 104 eyes of 80 patients who ranged in age from 24 to 99 years of age. Automatic local thresholding of the resultant raw data with the Phansalkar method was analyzed with generalized estimating equations. RESULTS:The distribution of flow voids vs size of the voids was highly skewed. The data showed a linear log-log plot and goodness-of-fit methods showed the data followed a power law distribution over the relevant range. A slope intercept relationship was also evaluated for the log transform and significant predictors for variables included age, hypertension, pseudodrusen, and the presence of late age-related macular degeneration (AMD) in the fellow eye. CONCLUSIONS:The pattern of flow voids forms a scale invariant pattern in the choriocapillaris starting at a size much smaller than a choroidal lobule. Age and hypertension affect the choriocapillaris, a flat layer of capillaries that may serve as an observable surrogate for the neural or systemic microvasculature. Significant alterations detectable in the flow pattern in eyes with pseudodrusen and in eyes with late AMD in the fellow eye offer diagnostic possibilities and impact theories of disease pathogenesis.