Predictors for 2-Year Functional and Morphological Outcomes of a Treat-and-Extend Regimen with Ranibizumab in Patients with Diabetic Macular Edema.

PURPOSE: The purpose of the study was to investigate longer term functional and morphological outcomes and their predictors in diabetic macular edema (DME) following a treat-and-extend regimen (TER) without loading dose under ranibizumab. METHODS: Patient data were reviewed and analyzed retrospectively over a period of 24 months after initiation of TER. Best-corrected visual acuity (BCVA), treatment frequency, and quantitative and qualitative spectral-domain optical coherence tomography parameters were assessed. RESULTS: 118 eyes of 87 patients were included. A mean of 9.74 ± 2.13 injections in the first and 7.63 ± 2.29 in the second year were applied. There were significant gains of BCVA and reductions in central retinal thickness from baseline to 12 and 24 months (all p < 0.001). Percentage of eyes with an intact inner segment/outer segment (IS/OS) junction increased from 15.3% at baseline to 42.1% at 24 months (p < 0.001). An intact IS/OS junction at baseline increased the probability of having a dry retina after 12 months by 79.3% (p = 0.017) and after 24 months by 88.1% (p = 0.040). Less IS/OS disruption at baseline predicted longer maximum recurrence-free treatment intervals at 2 years (r = -0.345, p < 0.001) and better BCVA at 1 year (r = -0.347, p < 0.001). Baseline bigger intraretinal cysts were associated with more IS/OS disruption at 24 months (r = 0.305, p = 0.007). Younger age and lower BCVA at baseline were predictive for a higher BCVA gain at 24 months (p = 0.046, p < 0.001). CONCLUSION: Ranibizumab applied in a TER without loading dose in DME significantly improves visual acuity and retinal anatomical structure throughout 2 years. The evaluated predictors might help guide routine clinical treatment in DME.

AUTOMATED RETINAL LAYER SEGMENTATION AND THEIR THICKNESS PROFILES IN HEALTHY SUBJECTS: A Comparison of 55° Wide-field and Conventional 30° Spectral Domain-Optical Coherence Tomography.

PURPOSE: To assess whether retinal thickness measurements with a standard 30° spectral domain optical coherence tomography (SD-OCT) are comparable with wide-field 55° SD-OCT. METHODS: Thirty-three healthy individuals were scanned using 55° as well as 30° SD-OCT according to a standardized protocol. Automated retinal layer segmentation of standard and wide-field SD-OCTs was assessed using customized software. RESULTS: Both lenses showed a high correlation when analyzing total retinal thickness within the central, the inner, and the outer retinal ring (r = > 0.9). Automated thickness measurements with the 55° system were marginally higher compared with the 30° lens. The thickness of each separate retinal layer using automated segmentation showed excellent correlations within the inner and outer rings (range: r = 0.6-r = 0.9 for the inner ring and range: r = 0.9-r = 1.0 for the outer ring). CONCLUSION: Fifty-five degree wide-field SD-OCT provides a good overview of the posterior pole and presents similar quantitative values as a standard 30° OCT lens. Therefore, thickness values are comparable when switching between these two lenses.

Comparison of Choroidal Thickness Measurements Using Spectral Domain Optical Coherence Tomography in Six Different Settings and With Customized Automated Segmentation Software.

PURPOSE: We investigate which spectral domain-optical coherence tomography (SD-OCT) setting is superior when measuring subfoveal choroidal thickness (CT) and compared results to an automated segmentation software. METHODS: Thirty patients underwent enhanced depth imaging (EDI)-OCT. B-scans were extracted in six different settings (W+N = white background/normal contrast 9; W+H = white background/maximum contrast 16; B+N = black background/normal contrast 12; B+H = black background/maximum contrast 16; C+N = Color-encoded image on black background at predefined contrast of 9, and C+H = Color-encoded image on black background at high/maximal contrast of 16), resulting in 180 images. Subfoveal CT was manually measured by nine graders and by automated segmentation software. Intraclass correlation (ICC) was assessed. RESULTS: ICC was higher in normal than in high contrast images, and better for achromatic black than for white background images. Achromatic images were better than color images. Highest ICC was achieved in B+N (ICC = 0.64), followed by B+H (ICC = 0.54), W+N, and W+H (ICC = 0.5 each). Weakest ICC was obtained with Spectral-color (ICC = 0.47). Mean manual CT versus mean computer estimated CT showed a correlation of r = 0.6 (P = 0.001). CONCLUSION: Black background with white image at normal contrast (B+N) seems the best setting to manually assess subfoveal CT. Automated assessment of CT seems to be a reliable tool for CT assessment. TRANSLATIONAL RELEVANCE: To define optimized OCT analysis settings to improve the evaluation of in vivo imaging.

Repeatability of Wide-field Optical Coherence Tomography Angiography in Normal Retina.

PURPOSE: We evaluated the repeatability of wide-field en face swept-source optical coherence tomography angiography (SS-OCTA) in healthy subjects. METHODS: Healthy subjects underwent two imaging sessions, on average 8 days apart, with a 100 kHz SS-OCTA instrument. The imaging protocol included a central 3 × 3 and 12 × 12 mm scans of the four quadrants resulting in more than a 70° wide-field OCTA of the posterior pole. Quantitative analysis was performed using the inbuilt Macular Density Algorithm Version v0.6.1 and AngioTool software. Consistency for the foveal avascular zone (FAZ), vessel density, and perfusion density of the superficial and deep capillary plexus slabs and the wide-field OCTA superficial slab, and the number of artefacts on the wide-field images were assessed. RESULTS: A total of 21 healthy volunteers (seven men and 14 women; mean age 32 years; range, 18-61; standard deviation, 10.28 years) were included in this analysis. Internal consistency was highest for FAZ area with an intraclass correlation (ICC) = 0.998 (95% confidence interval [CI], 0.997-0.999), a FAZ perimeter with an ICC = 0.995 (95% CI, 0.990-0.997), a FAZ circularity with an ICC= 0.976 (95% CI, 0.956-0.987), followed by the vessel density of the inner ring in the superficial slab with an ICC = 0.834 (95% CI, 0.691-0.911), and a vessel density of the inner ring in the deep slab with an ICC = 0.523 (95% CI, 0.113-0.744).The reproducibility of the average vessels length of the wide-field OCTA cropped images was strong (ICC = 0.801; 95% CI, 0.624-0.895), followed by the reproducibility of total number of junctions (ICC = 0.795; 95% CI, 0.613-0.892) and the vessels percentage area (ICC = 0.662; 95% CI, 0.361-0.821). CONCLUSIONS: The level of reproducibility for assessing the microvascular anatomy in wide-field OCTA is strong and can be used to quantify microvascular changes over time. Refinements in analysis strategies and a consensus of which parameters are most useful for quantitative assessment of wide-field OCTA images would be useful in the future. TRANSLATIONAL RELEVANCE: These findings bridge the gap between basic imaging research and clinical use for quantitative wide-field OCTA.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES OF TORPEDO MACULOPATHY.

BACKGROUND/PURPOSE: To investigate the retinal and choroidal vasculature in patients with torpedo maculopathy with optical coherence tomography-angiography (OCT-A). METHODS: Retrospective case series of four patients who were examined at the department of Ophthalmology at the University Hospital Bern. Main Outcome was the lesion size over time in OCT-A and fundus autofluorescence. RESULTS: Three patients had Type I and 1 patient had Type II torpedo maculopathy. Torpedo maculopathy lesion size remained stable in all patients over a mean period of observation of three years in OCT-A and fundus autofluorescence. The choriocapillaris network was attenuated focally within the lesion in OCT-A in all four cases. The lesion size in fundus autofluorescence was 2.77 mm and therefore comparable with the lesion size in OCT-A of 2.75 mm. CONCLUSION: OCT-A signal of the choriocapillaris was reduced within the cleft in both types of torpedo maculopathy. Whether the changes represent the primary site of malformation or whether these findings are the consequence of a defect in the retinal pigment epithelium remains speculative.

Atypical retinal pigment epithelial defects with retained photoreceptor layers: a so far disregarded finding in age related macular degeneration.

BACKGROUND: To report patients with age-related macular degeneration and atypical central retinal pigment epithelium (RPE) defects not attributable to geographic atrophy (GA) or RPE-tears with overlying preserved photoreceptor layers. METHODS: Multimodal imaging case-series evaluating the course of atypical RPE- defects in patients with AMD using Color fundus images, Optical coherence tomography (OCT), OCT-Angiography, fundus autofluorescence (FAF) and fluorescein-angiography (FA). RESULTS: Ten patients were identified. Three patients had a prior RPE-rip and were excluded. Seven patients with a mean follow-up period of 47 ± 38 months after the occurrence of the RPE-defect were included (age range 71-87 years). Mean distance Best corrected visual acuity (BCVA) at initial presentation was 0.36 ± 0.29logMAR and at last follow-up visit 0.51 ± 0.43logMAR. Patients presented with clinically apparent GA on funduscopy and FAF, but preserved photoreceptor layers on optical coherence tomography (OCT). On FA there was early hyperfluorescence and late pooling visible. Over time, migration of RPE/drusenoid material right above the Bruch's membrane with concomitant decrease of hypoautofluorescence was detectable in 4 cases. An enlargement of the RPE-defect was apparent in the remaining 3 cases. The majority (n = 4) showed a drusenoid pigment epithelium detachment (PED) preceding the lesion. CONCLUSIONS: Beside GA and characteristic RPE-tears, another atypical form of RPE-defect with overlying preserved photoreceptor layers are found in AMD. This so far disregarded subgroup of patients present with reasonable visual function and long-term survival of photoreceptors layers. Repair mechanisms such as ingrowth of RPE/drusenoid material and persistent subretinal fluid (SRF), but also a RPE-independent visual cycle for cone photopigment within the neurosensory retina may contribute to their favorable course.

OCT-angiography: A qualitative and quantitative comparison of 4 OCT-A devices.

PURPOSE: To compare the quality of four OCT-angiography(OCT-A) modules. METHOD: The retina of nineteen healthy volunteers were scanned with four OCT-devices (Topcon DRI-OCT Triton Swept-source OCT, Optovue RTVue-XR, a prototype Spectralis OCT2, Heidelberg-Engineering and Zeiss Cirrus 5000-HD-OCT). The device-software generated en-face OCT-A images of the superficial (SCP) and deep capillary plexuses (DCP) were evaluated and scored by 3 independent retinal imaging experts. The SCP vessel density was assessed using Angiotool-software. After the inter-grader reliability assessment, a consensus grading was performed and the modules were ranked based on their scoring. RESULTS: There was no significant difference in the vessel density among the modules (Zeiss 48.7±4%, Optovue 47.9±3%, Topcon 48.3±2%, Heidelberg 46.5±4%, p = 0.2). The numbers of discernible vessel-bifurcations differed significantly on each module (Zeiss 2±0.9 bifurcations, Optovue 2.5±1.2, Topcon 1.3±0.7 and Heidelberg 0.5±0.6, p≤0.001). The ranking of each module differed depending on the evaluated parameter. In the overall ranking, the Zeiss module was superior and in 90% better than the median (Bonferroni corrected p-value = 0.04). Optovue was better than the median in 60%, Topcon in 40% and Heidelberg module in 10%, however these differences were not statistically significant. CONCLUSION: Each of the four evaluated OCT-A modules had particular strengths, which differentiated it from their competitors.

Noninvasive Quantification of Retinal Microglia Using Widefield Autofluorescence Imaging.

Purpose: To validate widefield autofluorescence (AF) in vivo imaging of the retina in mice expressing green fluorescent protein (gfp) in microglia, and to monitor retinal microglia reconstitution in vivo after lethal irradiation and bone marrow transplantation. Methods: Transgenic Cx3cr1gfp/gfp and wildtype Balb/c mice were used in this study. A confocal scanning laser ophthalmoscope was used for AF imaging with a 55° and a widefield 102° lens. Intrasession reproducibility was assessed for each lens. To investigate reconstitution in vivo, bone marrow from Cx3cr1gfp/gfp mice was used to rescue lethally irradiated wildtype mice. Data were compared to confocal microscopy of retinal flat mounts. Results: Both the 55° and the 102° lens produced high resolution images of retinal microglia with similar microglia density. However, compared to the 55° lens, the widefield 102° lens captured approximately 3.6 times more microglia cells (1515 ± 123 cells versus 445 ± 76 cells [mean ± SD], for 102° and 55°, respectively, P < 0.001). No statistical difference in the number of gfp positive cells within corresponding areas was observed within the same imaging session. Imaging of microglia reconstitution showed a similar time course compared to flat mount preparations with an excellent correlation between microglia cell numbers in AF and gfp-stained flat mounts (R = 0.92, P < 0.0001). Conclusions: Widefield AF imaging of mice with gfp expressing microglia can be used to quantify retinal microglia. In vivo microglia counts corresponded very well with ex vivo counts on retinal flat mounts. As such, AF imaging can largely replace ex vivo quantification.

Comparison of 55° Wide-Field Spectral Domain Optical Coherence Tomography and Conventional 30° Optical Coherence Tomography for the Assessment of Diabetic Macular Edema.

PURPOSE: To compare conventional 30° spectral domain optical coherence tomography (SD-OCT) with 55° wide-field SD-OCT for the assessment of diabetic macular edema (DME). METHODS: This study included 50 DME patients. Both 55° and 30° SD-OCT was conducted. Two readers evaluated scans according to a standardized grading protocol. Intergrader agreement as well as agreement between 30° and 55° SD-OCT were assessed. RESULTS: Intergrader agreement (κ) was strong and ranged from 0.79 to 1.0. Perfect interdevice agreement (κ = 1.0) was found for the detection of intra- and subretinal fluid. Excellent agreement (κ ≥ 0.9) was found for the presence of epiretinal membrane (κ = 0.92) and cotton-wool spots (κ = 0.92). A strong agreement was found for the presence of hard exudates (κ = 0.89) and microaneurysms (κ = 0.81). A moderate correlation was found for ellipsoid zone integrity (κ = 0.69) and configuration of the vitreomacular interface (VMI) (κ = 0.69). A weak agreement was found for retinal pigment epithelium atrophy (κ = 0.51) and external limiting membrane integrity (κ = 0.35). CONCLUSION: Wide-field OCT imaging may be beneficial for evaluating DME, particularly for assessing the VMI and the integrity of hyperreflective bands.

Outcomes when Switching from a pro re nata Regimen to a Treat and Extend Regimen Using Aflibercept in Neovascular Age-Related Macular Degeneration.

PURPOSE: To investigate outcomes in patients with neovascular age-related macular degeneration (AMD) switched from a pro re nata regimen (PRN) to a treat and extend regimen (TER) under aflibercept. PROCEDURE: Thirty-two patients were observed over 2 years: the first year on PRN and the second year on TER. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were evaluated. Intra- and subretinal fluid as well as the number of visits and injections were assessed. RESULTS: Both regimens resulted in a stable BCVA. Patients in TER had a significant decrease of CRT after 1 year compared to 1 year of treatment on PRN (p < 0.0001). TER resulted in significantly less visits; however, significantly more injections were observed over the course of 1 year compared to PRN (10.25 vs. 7.5, p < 0.0001 and 5.97 vs. 7.5, p = 0.0002, respectively). CONCLUSION: A switch from PRN to TER in patients treated with aflibercept for AMD appears to be safe.

Optical Coherence Tomography Angiography in Mice: Comparison with Confocal Scanning Laser Microscopy and Fluorescein Angiography.

PURPOSE: Optical coherence tomography angiography (OCT-A) allows noninvasive visualization of retinal vessels in vivo. OCT-A was used to characterize the vascular network of the mouse retina and was compared with fluorescein angiography (FA) and histology. METHODS: In the present study, OCT-A based on a Heidelberg Engineering Spectralis system was used to investigate the vascular network in mice. Data was compared with FA and confocal microscopy of flat-mount histology stained with isolectin IB4. For quantitative analysis the National Cancer Institute's AngioTool software was used. Vessel density, the number of vessel junctions, and endpoints were measured and compared between the imaging modalities. RESULTS: The configuration of the superficial capillary network was comparable with OCT-A and flat-mount histology in BALBc mice. However, vessel density and the number of vessel junctions per region of interest (P = 0.0161 and P = 0.0015, respectively) in the deep vascular network of BALBc mice measured by OCT-A was significantly higher than with flat-mount histology. In C3A.Cg-Pde6b+Prph2Rd2/J mice, where the deep capillary plexus is absent, analysis of the superficial network provided similar results for all three imaging modalities. CONCLUSION: OCT-A is a helpful imaging tool for noninvasive, in vivo imaging of the vascular plexus in mice. It may offer advantages over FA and confocal microscopy especially for imaging the deep vascular plexus. TRANSLATIONAL RELEVANCE: The present study shows that OCT-A can be employed for small animal imaging to assess the vascular network and offers advantages over flat-mount histology and FA.