Faculty Bibliography

PURPOSE: To examine the colocalization error between the infrared reflectance (IR) scanning laser ophthalmoscope (SLO) and spectral domain optical coherence tomography (SD-OCT) images of the Heidelberg Spectralis. METHODS: The IR and corresponding horizontal raster SD-OCT images were compared in 10 healthy volunteers examined with 3 Heidelberg Spectralis + OCT instruments. The center points of retinal vessels selected by random uniform sampling in scanning laser ophthalmoscope-IR images were compared with colocalizing points in corresponding SD-OCT images by two masked readers. The error of colocalization was measured in the SD-OCT image. The point positions were recorded using Cartesian coordinates measured in microns. The error of colocalization was evaluated using a fixed-effects generalized least squares regression model with location and instrument as predictor variables. RESULTS: A total of 1,617 points in the IR and SD-OCT images were analyzed, and the mean error of colocalization was 42.2 +/- 32.4 mum. The Heidelberg Spectralis instrument used was not a significant predictor of colocalization error (P = 0.15). The colocalization errors were negatively correlated with x-coordinate position (P < 0.001). CONCLUSION: There is a mean colocalization error between the IR and SD-OCT images produced by the Heidelberg Spectralis that is on the scale of many features being evaluated in the fundus. The variability in these measurements means the confidence interval for the exact colocalization is much larger. Because of the magnitude and variability of the error, the colocalization feature of the Heidelberg Spectralis should be used as a rough guide, not an absolute determinant.

PURPOSE: To evaluate eyes with refractile drusen using clinical imaging and to identify candidate histologic correlates of refractile drusen. METHODS: Refractile drusen were defined as drusenoid material containing small refractile spherules. Retrospective analysis of color, autofluorescence, and spectral domain optical coherence tomography images of eyes with refractile drusen was performed to characterize the morphology and topography of these lesions. Macular sections from donor eyes were processed with a von Kossa stain for calcium phosphate and viewed by light microscopy. Punches of retinal pigment epithelium-choroid from donors with geographic atrophy were prepared for transmission electron microscopy. RESULTS: Fundus findings of 14 eyes of 10 patients with age-related macular degeneration (age, 82.9 +/- 5.6 years) were evaluated. A generalized loss of autofluorescence signal over refractile drusen appeared to spread over a larger area than each druse, for drusen located centrally. By color fundus photography, refractile drusen showed corresponding depigmentation around drusen that were located in the center of the macula. Optical coherence tomography imaging of refractile drusen showed hyperreflective dots. In the histologic specimens, drusen contained many small spherules rich in calcium phosphate. Ultrastructural examination of the spherules showed complex assemblies consisting of concentric shells containing thin layers of calcium. CONCLUSION: Refractile drusen appear to be a stage of drusen regression marked by loss of retinal pigment epithelium, thus contributing to the development of geographic atrophy. Calcium-containing spherules appear to account for the glistening appearance.

PURPOSE:: To compare the functional and morphologic characteristics and evolution of lamellar macular holes (LMHs) with and without lamellar hole-associated epiretinal proliferation (LHEP). METHODS:: This was a retrospective observational case review of 145 eyes of 136 patients with LMH seen in a vitreoretinal clinical practice, and the eyes were subdivided into 2 groups based on the presence or absence of LHEP. Main outcome measures were logarithm of minimal angle of resolution (logMAR) visual acuity and morphologic characteristics as seen with spectral domain optical coherence tomography over retrospective follow-up. RESULTS:: In 62 eyes (42.7%), LHEP was detected, while 83 eyes (57.3%) had the presence of epiretinal membrane without LHEP. The mean logMAR visual acuity in eyes with LHEP was 0.51 (20/65 Snellen equivalent), which was significantly poorer than that in the eyes without LHEP at 0.33 (20/43 Snellen equivalent, P = 0.002). Multivariate analysis showed that the presence of LHEP was significantly associated with larger LMH diameter at the middle retinal level (P = 0.01) and thinner retinal thickness at the base of the LMH (P < 0.001). A higher proportion of eyes with LHEP (88%) had ellipsoid disruption compared with eyes without LHEP (24%, P = 0.001). Over the mean retrospective follow-up of 26 months, 5% of eyes with LHEP had functional decline of 0.3 logMAR visual acuity compared with 4% of eyes without LHEP (P = 0.99), whereas 18% of eyes with LHEP had morphologic progression compared with 13% of eyes without LHEP (P = 0.49). CONCLUSION:: Eyes with LMH and LHEP were associated with poorer visual acuity, larger LMH diameters, thinner retinal thickness, and higher incidence of ellipsoid disruption compared with eyes without LHEP, suggesting a process involving more severe retinal tissue loss and injury. Both LMH with and without LHEP seemed to be stable configurations over time.

PURPOSE:: To demonstrate the evolution and treatment response of Type 3 neovascularization using spectral domain optical coherence tomography. METHODS:: We retrospectively analyzed 40 eyes treated with intravitreal anti-vascular endothelial growth factor therapy for Type 3 neovascularization over a variable follow-up period. RESULTS:: In 17 eyes, spectral domain optical coherence tomography captured the development of Type 3 neovascularization from punctate hyperreflective foci that preceded any outer retinal defect. The more mature Type 3 lesions were associated with outer retinal disruption and adjacent cystoid macular edema. In addition, 37 of 40 Type 3 lesions (93%) were associated with an underlying pigment epithelial detachment, of which 26 (70%) were drusenoid, 6 (16%) serous, and 5 (14%) mixed. Type 3 vessels appeared to leak fluid into the pigment epithelial detachment cavity, creating serous pigment epithelial detachments as large as 925 mum in maximal height. Treatment with anti-vascular endothelial growth factor agents led to prompt involution of the lesion and resorption of the intraretinal and subretinal pigment epithelium fluid after one or two injections (median = 1). CONCLUSION:: In some eyes with age-related macular degeneration, the earliest sign of Type 3 neovascularization is punctate hyperreflective foci above the external limiting membrane. The mature Type 3 lesions and associated serous pigment epithelial detachments are highly responsive to anti-vascular endothelial growth factor therapy.

PURPOSE:: The aim of this study was to characterize peau d'orange and angioid streaks, characteristic findings in eyes of patients with pseudoxanthoma elasticum, by examining fundus photography and optical coherence tomography imaging. METHODS:: Color photographs were evaluated directly as were the component red and green channels. Optical coherence tomography images were evaluated for reflectivity pattern of the band corresponding to the retinal pigment epithelium-Bruch membrane complex. RESULTS:: Eighteen eyes of 9 patients with a mean age of 48.7 years (range, 31-61 years) were examined; 7 of them were women. Color photographs showed areas of yellowish opacification that obscured visualization of the underlying choroid. At the outer edges of this confluent area, opacification were nonconfluent changes with similar appearance and these regions were typical peau d'orange. Angioid streaks occurred within and extended up to the outer border of the confluent opacification. Underlying choroidal details could be seen through the regions of peau d'orange and through the gaps in angioid streaks. The red channel image showed increased reflectivity from the confluent deposit and improved visualization of the choroidal vasculature, except where the confluent opacification was located. Optical coherence tomography imaging showed increased reflectivity from the outer border of the retinal pigment epithelium-Bruch membrane complex. CONCLUSION:: The findings suggest that the confluent region is the relevant lesion, not the subconfluent zone known as peau d'orange. Imaging characteristics of the confluent area of opacity are consistent with diffuse infiltration with calcium, a chief histologic abnormality of pseudoxanthoma elasticum. The name coquille d'oeuf was suggested for the confluent area of opacity as a consequence.

Importance: Macular telangiectasia type 2 (MacTel 2) is a rare disease in which abnormalities of the retinal vasculature play a key role. The vascular abnormalities are typically evaluated using fluorescein angiography, a modality with known defects in imaging the deeper layers of the retinal vasculature. Angiography based on optical coherence tomography can image vessels based on flow characteristics without dye injection and may provide improved information concerning the pathophysiology of MacTel 2. Objective: To investigate MacTel 2 using optical coherence tomographic angiography. Design, Setting, and Participants: Fourteen eyes of 7 patients with MacTel 2 were analyzed in a community-based retina practice. The flow imaging was based on split-spectrum amplitude decorrelation angiography, which can dissect layers of vessels in the retina. The inner retinal vascular plexus, the outer plexus, and deeper vascular invasion into the outer and subretinal spaces were optically dissected in en face images based on flow. Main Outcomes and Measures: Visualization and qualitative evaluation of the vascular layers of the retina as they may be affected by MacTel 2, both in terms of depth and topographic characteristics. Results: A consistent set of retinal vascular changes were seen in the eyes with MacTel 2. There was some loss of capillary density in the inner retinal vascular plexus but many more prominent alterations in the deep retinal vascular plexus. In milder forms of the disease, the deep plexus showed dilation and telangiectasis and, in more advanced cases, thinning and loss. The remaining vessels were elongated and widely spaced capillary segments. Invasion by new vessels into the outer and subretinal spaces occurred subjacent to the regions showing greatest flow imaging abnormalities in the inner and deep retinal vascular layers. Conclusions and Relevance: As evidenced by the patients in this study, important retinal vascular changes in MacTel 2 occur in the deep capillary plexus of the retina, a layer poorly visualized by fluorescein angiography and, to a lesser extent, in the inner vascular plexus. The proliferation of vessels in the outer and subretinal spaces may be in part compensatory for poor retinal perfusion by established vascular layers in the retina.

Importance: The retinal vasculature is involved in many ocular diseases that cause visual loss. Although fluorescein angiography is the criterion standard for evaluating the retina vasculature, it has risks of adverse effects and known defects in imaging all the layers of the retinal vasculature. Optical coherence tomography (OCT) angiography can image vessels based on flow characteristics and may provide improved information. Objective: To investigate the ability of OCT angiography to image the vascular layers within the retina compared with conventional fluorescein angiography. Design, Setting, and Participants: In this study, performed from March 14, 2014, through June 24, 2014, a total of 5 consecutive, overlapping B-scan OCT angiography images composed of 216 A-scans were obtained at 216 discrete positions within a region of interest, typically a 2 x 2-mm area of the retina. The flow imaging was based on split-spectrum amplitude decorrelation angiography (SSADA), which can dissect layers of vessels in the retina. These distinct layers were compared with the fluorescein angiograms in 12 healthy eyes from patients at a private practice retina clinic to evaluate the ability to visualize the radial peripapillary capillary network. The proportion of the inner vs outer retinal vascular layers was estimated by 3 masked readers and compared with conventional fluorescein angiograms of the same eyes. Main Outcomes and Measures: Outcome measures were visualization of the radial peripapillary capillary network in the fluorescein and SSADA scans and the proportion of the inner retinal vascular plexus vs the outer retinal capillary plexus as seen in SSADA scans that would match the fluorescein angiogram. Results: In none of the 12 eyes could the radial peripapillary capillary network be visualized completely around the nerve head by fluorescein angiography, whereas the network was readily visualized in the SSADA scans. The fluorescein angiograms were matched, with a mean proportion of the inner vascular plexus being 95.3% (95% CI, 92.2%-97.8%) vs 4.7% (95% CI, 2.6%-5.7%) for the outer capillary plexus from the SSADA scans. Conclusions and Relevance: Fluorescein angiography does not image the radial peripapillary or the deep capillary networks well. However, OCT angiography can image all layers of the retinal vasculature without dye injection. Therefore, OCT angiography, and the findings generated, have the potential to affect clinical evaluation of the retina in healthy patients and patients with disease.