Intereye Microvascular Differences in Patients With Same-Stage Diabetic Retinopathy Revealed by OCTA.

Purpose: To evaluate microvascular intereye differences in diabetic patients with same-stage diabetic retinopathy (DR) in both eyes as assessed using optical coherence tomography angiography (OCTA). Methods: In this cross-sectional study, fovea-centered swept-source 6 × 6 mm OCTA scans were acquired using a 200 kHz OCTA device. Vessel density (VD) and fractal dimension were calculated on binarized, vessel-segmented images in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). Foveal avascular zone (FAZ) area (FAZA) and perimeter (FAZP) was measured and FAZ circularity (FAZC) calculated. Absolute difference (δabs) and asymmetry index between eyes was assessed and compared across DR stages. Differences of VD, FD, and FAZ parameters between left and right eye were evaluated using linear mixed models. Results: A total of 336 eyes of 168 diabetic patients without DR and with DR stages ranging from mild nonproliferative to proliferative DR were included for analysis. The intereye comparison revealed significantly lower VD in the SCP (estimate [95% CI] = -0.009 [-0.01; -0.006], P < 0.01), as well as a significantly lower FD in the SCP (-0.007 [-0.009; -0.005], P < 0.01) of the left compared to the right eye. FAZC of the left compared to the right eye was lower in eyes without DR, moderate DR, and PDR (P < 0.05). FAZ δabs and asymmetry index were higher in more advanced disease stages (P < 0.05). Conclusions: OCTA metrics provide important information on the retinal microvasculature in systemic diseases such as DR. Our results reveal a significant intereye difference with lower VD and FD in the SCP as well as higher FAZ impairment of the left compared to the right eye.

Microaneurysm detection using high-speed megahertz optical coherence tomography angiography in advanced diabetic retinopathy.

PURPOSE: To compare detection rates of microaneurysms (MAs) on high-speed megahertz optical coherence tomography angiography (MHz-OCTA), fluorescein angiography (FA) and colour fundus photography (CF) in patients with diabetic retinopathy (DR). METHODS: For this exploratory cross-sectional study, MHz-OCTA data were acquired with a swept-source OCT prototype (A-scan rate: 1.7 MHz), and FA and CF imaging was performed using Optos® California. MA count was manually evaluated on en face MHz-OCTA/FA/CF images within an extended ETDRS grid. Detectability of MAs visible on FA images was evaluated on corresponding MHz-OCTA and CF images. MA distribution and leakage were correlated with detectability on OCTA and CF imaging. RESULTS: 47 eyes with severe DR (n = 12) and proliferative DR (n = 35) were included. MHz-OCTA and CF imaging detected on average 56% and 36% of MAs, respectively. MHz-OCTA detection rate was significantly higher than CF (p < 0.01). The combination of MHz-OCTA and CF leads to an increased detection rate of 70%. There was no statistically significant association between leakage and MA detectability on OCTA (p = 0.13). For CF, the odds of detecting leaking MAs were significantly lower than non-leaking MAs (p = 0.012). Using MHz-OCTA, detection of MAs outside the ETDRS grid was less likely than MAs located within the ETDRS grid (outer ring, p < 0.01; inner ring, p = 0.028). No statistically significant difference between rings was observed for CF measurements. CONCLUSIONS: More MAs were detected on MHz-OCTA than on CF imaging. Detection rate was lower for MAs located outside the macular region with MHz-OCTA and for leaking MAs with CF imaging. Combining both non-invasive modalities can improve MA detection.

Macular Microvascular Perfusion Status in Hypertensive Patients with Chronic Kidney Disease.

To compare retinal microvascular perfusion between the eyes of hypertensive patients with and without chronic kidney disease (CKD), the vessel density (VD) and fractal dimension (FD) of the superficial (SVP) and deep retinal vascular plexus (DVP) were analyzed on 6 × 6 mm fovea-centered optical coherence tomography angiography (OCTA) images of patients with hypertension. The retina was divided into an inner ring (IR) and outer ring (OR) according to the Early Treatment of Diabetic Retinopathy Study grid. The glomerular filtration rate (GFR) was determined and CKD was diagnosed (GFR < 60 mL/min/1.73 m2). Ninety-six eyes from 52 patients with hypertension were included in this analysis. Twenty patients (n = 37 eyes) were diagnosed with CKD. The mean age was 69 ± 11.7 years and 60.4 ± 9.2 years in the CKD group and in the control group, respectively. The univariate model revealed a significant difference in VD between patients without and with CKD in the superficial IR (0.36 ± 0.03 vs. 0.34 ± 0.04, p = 0.03), the superficial OR (0.35 ± 0.02 vs. 0.33 ± 0.04, p = 0.02), the deep OR (0.24 ± 0.01 vs. 0.23 ± 0.02, p = 0.003), and the FD in the SVP (1.87 ± 0.01 vs. 1.86 ± 0.02, p = 0.02) and DVP (1.83 ± 0.01 vs. 1.82 ± 0.01, p = 0.006). After adjusting for age and sex, these differences did not remain statistically significant. Similar results were observed for the FD in the SVP and DVP. In our cohort, patients with hypertension and CKD did not differ from patients without CKD in regard to microvascular perfusion status in the macular area as assessed using OCTA.

Association of Diabetic Lesions and Retinal Nonperfusion Using Widefield Multimodal Imaging.

PURPOSE: To evaluate the association of microvascular lesions on ultrawidefield (UWF) color fundus (CF) images with retinal nonperfusion (RNP) up to the midperiphery on single-capture widefield (WF) OCT angiography (OCTA) in patients with diabetic retinopathy (DR). DESIGN: Cross-sectional study. SUBJECTS: Seventy-five eyes of 50 patients with mild to severe nonproliferative DR (NPDR) and proliferative DR (PDR) were included in this analysis. METHODS: ETDRS level and presence of predominantly peripheral lesions (PPLs) were assessed on UWF-CF images acquired with a Zeiss Clarus 700. Single-capture 65°-WF-OCTA was performed using a PlexElite prototype (Carl Zeiss Meditec, Inc.). A custom grid consisting of a central ETDRS grid extended by 2 rings reaching up to the midperiphery was overlaid to subdivide retinal areas visible on WF-OCTA en face images. Retinal nonperfusion was measured in each area and in total. Nonperfusion index (NPI) was calculated from total RNP. On UWF-CF images, the number of microaneurysms, hemorrhages, neovascularizations, and areas with intraretinal microvascular abnormalities (IRMAs) were evaluated using the same grid. MAIN OUTCOME MEASURES: Association of diabetic lesions with RNP was calculated using Spearman correlations (rs). RESULTS: Median RNP on WF-OCTA was 0 mm2 (0-0.9), 4.9 mm2 (1.9-5.4), 23.4 mm2 (17.8-37), and 68.4 mm2 (40.8-91.7) in mild, moderate, and severe NPDR and PDR, respectively. We found a statistically significant correlation (P < 0.01) of overall RNP (rs = 0.96,) and NPI (rs = 0.97) on WF-OCTA with ETDRS level. Number of grid-fields affected by IRMAs on CF images was highly associated with NPI (rs = 0.86, P < 0.01). Intraretinal microvascular abnormalities and RNPs had similar topographic distributions with high correlations in affected areas. Eyes with PPLs (n = 43 eyes, 57%) on CF images had a significantly higher NPI (P = 0.014) than eyes without PPLs. CONCLUSION: The combination of UWF-CF imaging and single-capture WF-OCTA allows precise and noninvasive analysis of the retinal vasculature up to the midperiphery in patients with DR. The presence and extent of IRMAs on CF images may serve as an indicator for underlying RNP, which is more pronounced in eyes with PPLs. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Multiple instance learning based classification of diabetic retinopathy in weakly-labeled widefield OCTA en face images.

Diabetic retinopathy (DR), a pathologic change of the human retinal vasculature, is the leading cause of blindness in working-age adults with diabetes mellitus. Optical coherence tomography angiography (OCTA), a functional extension of optical coherence tomography, has shown potential as a tool for early diagnosis of DR through its ability to visualize the retinal vasculature in all spatial dimensions. Previously introduced deep learning-based classifiers were able to support the detection of DR in OCTA images, but require expert labeling at the pixel level, a labor-intensive and expensive process. We present a multiple instance learning-based network, MIL-ResNet,14 that is capable of detecting biomarkers in an OCTA dataset with high accuracy, without the need for annotations other than the information whether a scan is from a diabetic patient or not. The dataset we used for this study was acquired with a diagnostic ultra-widefield swept-source OCT device with a MHz A-scan rate. We were able to show that our proposed method outperforms previous state-of-the-art networks for this classification task, ResNet14 and VGG16. In addition, our network pays special attention to clinically relevant biomarkers and is robust against adversarial attacks. Therefore, we believe that it could serve as a powerful diagnostic decision support tool for clinical ophthalmic screening.

Detection of diabetic neovascularisation using single-capture 65°-widefield optical coherence tomography angiography.

AIM: To assess the detection rate of retinal neovascularisation (NV) in eyes with proliferative diabetic retinopathy (PDR) using widefield optical coherence tomography angiography (WF-OCTA) in comparison to ultrawidefield fluorescein angiography (UWF-FA). METHODS: Single-capture 65°-WF-OCTA-imaging was performed in patients with NV at the disc or elsewhere (NVE) detected on UWF-FA using a modified PlexElite system and B-scans were examined for blood flow signals breaching the internal limiting membrane. Sensitivity of WF-OCTA and UWF colour fundus (UWF-CF) photography for correct diagnosis of PDR was determined and interdevice agreement (Fleiss' κ) between WF-OCTA and UWF-FA for detection of NV in the total gradable area and each retinal quadrant was evaluated. RESULTS: Fifty-nine eyes of 41 patients with PDR detected on UWF-FA were included. Sensitivity of detecting PDR on WF-OCTA scans was 0.95 in contrast to 0.78 on UWF-CF images. Agreement in detecting NVE between WF-OCTA and UWF-FA was high in the superotemporal (κ=0.98) and inferotemporal (κ=0.94) and weak in the superonasal (κ=0.24) and inferonasal quadrants (κ=0.42). On UWF-FA, 63% of NVEs (n=153) were located in the temporal quadrants with 93% (n=142) of them being detected on WF-OCTA scans. CONCLUSION: The high reliability of non-invasive WF-OCTA imaging in detecting PDR can improve clinical examination with the potential to replace FA as a single diagnostic tool.

Comparison of two ultra-widefield color-fundus imaging devices for visualization of retinal periphery and microvascular lesions in patients with early diabetic retinopathy.

Comparison of two ultra-widefield (UWF) color-fundus (CF) imaging devices in diabetic patients for visualization of retinal periphery and detection of early microvascular lesions. The total gradable areas (TGA) seen on non-mydriatic CF-images of two UWF-imaging devices (Optos Daytona P200T; Zeiss Clarus 700) were compared and differences in projected area measured. Retinal periphery outside the 7 standard fields (7SF) was divided into: F3 temporal, F4 superotemporal, F5 inferotemporal, F6 superonasal, F7 inferonasal. DR stage was evaluated in the 7SF and the TGA on images of both devices and compared using Cohens κ. 67 eyes of 67 patients (52.5 ± 15.3 years) were analysed. DR stages in the 7SF were no (n = 36 Optos, n = 35 Clarus), mild (n = 16 Optos, n = 17 Clarus), and moderate DR (n = 15). Optos depicted significantly more area in F3 (median [interquartile range]; 2.41% [1.06-4.11] vs 0% [0-0], P < 0.001) and Clarus in F7 (3.29% [0-7.69] vs 0% [0-3.27], P = 0.002). In 4 eyes DR-stage was higher using Optos due to peripheral lesions not seen on the Clarus. Interrater reliability of DR-stage on both devices was almost perfect in the 7SF (κ = 0.975) and the TGA (κ = 0.855). Reliability in detecting signs of early DR is high on both devices. Clarus allowed for better visualization of the inferonasal field, Optos of the temporal field.

Evaluation of neuroretinal integrity in optical coherence tomography-graded eyes with partial-thickness macular holes.

PURPOSE: To evaluate neuroretinal integrity in different subtypes of optical coherence tomography (OCT)-graded partial-thickness macular holes. METHODS: Fovea-centred SD-OCT images (Cirrus, Carl Zeiss Meditec AG; Spectralis, Heidelberg Engineering GmbH) and visual acuity (VA) acquired at every visit were analysed by two retina specialists retrospectively in 71 eyes of 65 patients. Partial-thickness macular holes were classified as lamellar macular hole (LMH), epiretinal membrane foveoschisis (ERMF) or macular pseudohole (MPH). RESULTS: Lamellar macular hole, ERMF and MPH were diagnosed in 33 (47%), 31 (43%) and 7 (10%) eyes with a VA of 0.18 ± 0.25, 0.15 ± 0.2, and 0.06 ± 0.08 (p = 0.323), respectively. Median follow-up time was 11 (interquartile range 4-32.5), 10 (interquartile range 5-18) and 19 (interquartile range 8-24) months in LMH, ERMF and MPH. In all subgroups, VA remained stable during the follow-up (p = 0.652, p = 0.915 and p = 1.000). Epiretinal proliferations (EP) were present in 12 LMH and 3 ERMF. At baseline, eyes with EP had significantly worse VA (p < 0.001), wider foveal cavities (p = 0.007) and thinner foveal floors (p < 0.001) compared with eyes without EP. Twelve out of 15 eyes with EP showed exudative cystoid spaces. Among all 71 eyes, 51 remained morphologically and functionally stable during follow-up. CONCLUSION: In our study cohort, EP are associated with worse VA and advanced neuroretinal tissue loss presenting with wider foveal cavities and thinner foveal floors. During the follow-up period, VA remained stable in all entities of partial-thickness macular holes.

Current rates of prosthetic usage in upper-limb amputees - have innovations had an impact on device acceptance?

PURPOSE: There is a large body of evidence demonstrating high rates of prosthesis abandonment in the upper extremity. However, these surveys were conducted years ago, thus the influence of recent refinements in prosthetic technology on acceptance is unknown. This study aims to gather current data on prosthetic usage, to assess the effects of these advancements. MATERIALS AND METHODS: A questionnaire was sent to 68 traumatic upper limb amputees treated within the Austrian Trauma Insurance Agency between the years 1996 and 2016. Responses were grouped by the year of amputation to assess the effect of time. RESULTS: The rejection rate at all levels of amputation was 44%. There was no significant difference in acceptance between responders amputated before or after 2006 (p = 0.939). Among users, 92.86% (n = 13) used a myoelectric, while only one amputee (7.14%, n = 1) used a body-powered device. Most responders complained about the comfort (60.87%, n = 14) as well as the weight of the device (52.17%, n = 12). CONCLUSIONS: The advancements of the last decade in the arena of upper limb prosthetics have not yet achieved a significant change in prosthetic abandonment within this study cohort. Although academic solutions have been presented to tackle patient's complaints, clinical reality still shows high rejection rates of cost-intensive prosthetic devices.Implications for rehabilitationAbandonment rates in prosthetic rehabilitation after upper limb amputation have shown to be 50% and higher.The advancements of the last decade in the arena of upper limb prosthetics have not yet achieved a significant change in prosthetic abandonment.Well-structured and patient-tailored prosthetic training as well as ensuring the amputee's active participation in the decision making process will most likely improve prosthetic acceptance.