We use the prototype swept-source (SS) OCT at 1060 nm to image human Schlemm's canal (SC) and perform full reconstruction in the en face plane. Compared with spectral-domain (SD) OCT systems at 800 nm, the SS OCT system at 1060 nm offers deeper signal penetration, and has no sensitivity roll-off effect to allow for better localization and delineation of SC. One volumetric scan was taken from each of the eight cardinal positions to cover the entire SC circumferentially around the limbus. The en face slices were taken from each volume at the SC region, and were stitched together to generate an en face representation of the 360 deg SC.
In Brief Purpose: To evaluate the performance of polypoidal choroidal vasculopathy (PCV) diagnosis using fundus camera-based indocyanine green angiography, comparing a single sign of “subretinal focal hyperfluorescence” on indocyanine green angiography with a modification of the EVEREST criteria. Methods: Color fundus photograph, flash fundus camera-based fluorescein angiography, and indocyanine green angiography of 241 eyes of 230 consecutive patients with exudative maculopathy due to PCV or typical age-related macular degeneration were graded independently by 2 retinal specialists using a modified EVEREST criteria, which requires the presence of subretinal focal hyperfluorescence plus any 1 of 5 additional criteria. Discordant cases were adjudicated by a senior retinal specialist to arrive at the final diagnosis. Sensitivity, specificity, and area under the receiver operating curve of subretinal focal hyperfluorescence versus the EVEREST criteria and combinations of individual EVEREST criteria were compared. Results: Among the 241 eyes with exudative maculopathy, 131 eyes had PCV and 110 eyes had typical age-related macular degeneration. Using a single sign of subretinal focal hyperfluorescence alone for the diagnosis of PCV, sensitivity was 85.3% and specificity was 80.9%, with an area under the receiver operating curve of 83.1%. When applying the EVEREST definition, sensitivity was reduced to 78.4% but specificity improved to 87.1% with a similar area under the receiver operating curve of 82.8%. The frequency of individual criteria was highly variable, with stereo nodular appearance (73.7%) and orange nodule (55.0%) being the most common and branching vascular network, massive hemorrhage, and hypofluorescent halo in the presence of subretinal focal hyperfluorescence being less common (21.5%–28.1%). Conclusion: The EVEREST criteria have a higher specificity for the diagnosis of PCV than subretinal focal hyperfluorescence alone and may be applied to flash fundus camera-based indocyanine green angiography in a clinical setting. Stereo nodular appearance is the most important additional criterion. The EVEREST criteria has a higher specificity for the diagnosis of polypoidal choroidal vasculopathy than subretinal focal hyperfluorescence alone and may be applied to flash fundus camera-based indocyanine green angiography in a clinical setting.
Glaucoma is a chronic eye disease that leads to vision loss. As it cannot be cured, detecting the disease in time is important. Current tests using intraocular pressure (IOP) are not sensitive enough for population based glaucoma screening. Optic nerve head assessment in retinal fundus images is both more promising and superior. This paper proposes optic disc and optic cup segmentation using superpixel classification for glaucoma screening. In optic disc segmentation, histograms, and center surround statistics are used to classify each superpixel as disc or non-disc. A self-assessment reliability score is computed to evaluate the quality of the automated optic disc segmentation. For optic cup segmentation, in addition to the histograms and center surround statistics, the location information is also included into the feature space to boost the performance. The proposed segmentation methods have been evaluated in a database of 650 images with optic disc and optic cup boundaries manually marked by trained professionals. Experimental results show an average overlapping error of 9.5% and 24.1% in optic disc and optic cup segmentation, respectively. The results also show an increase in overlapping error as the reliability score is reduced, which justifies the effectiveness of the self-assessment. The segmented optic disc and optic cup are then used to compute the cup to disc ratio for glaucoma screening. Our proposed method achieves areas under curve of 0.800 and 0.822 in two data sets, which is higher than other methods. The methods can be used for segmentation and glaucoma screening. The self-assessment will be used as an indicator of cases with large errors and enhance the clinical deployment of the automatic segmentation and screening.
Objective To study the treatment patterns and visual outcome over one year in Asian patients with choroidal neovascular membrane secondary to age-related macular degeneration (AMD-CNV) and polypoidal choroidal vasculopathy (PCV). Design Prospective cohort, non-interventional study. Methods 132 treatment-naïve patients who received treatment for AMD-CNV and PCV were included. All patients underwent standardized examination procedures including retinal imaging at baseline and follow-up. AMD-CNV and PCV were defined on fundus fluorescein angiography and indocyanine green angiography at baseline. Patients were treated according to standard of care.We report the visual acuity (VA) and optical coherence tomography (OCT) measurements at baseline, month 3 and month 12 The factors influencing month 12 outcomes were analyzed. Main Outcome Measure Type of treatment, number of Anti-vascular endothelial growth factor (VEGF) treatments, visual outcome over one year. Results Anti-VEGF monotherapy was the initial treatment in 89.1% of AMD-CNV, but only 15.1% of PCV. The mean number of anti-VEGF injections up to month 12 was 3.97 (4.51 AMD-CNV, 3.43 PCV, p = 0.021). Baseline OCT, month 3 OCT and month 3 VA were significant in determining continuation of treatment after month 3. At month12, mean VA improved from 0.82 (∼20/132) at baseline to 0.68 (∼20/96) at month 12 (mean gain 6.5 ETDRS letters, p = 0.002). 34.2% of eyes (38/113 eyes) gained ≥15 ETDRS letters and 14.4% (16/113 eyes) lost ≥15 ETDRS letters. There were no significant differences in visual outcome between AMD-CNV and PCV (p = 0.51). Factors predictive of month 12 visual outcome were baseline VA, baseline OCT central macular thickness, month 3 VA and age. Conclusions There is significant variation in treatment patterns in Asian eyes with exudative maculopathy. There is significant visual improvement in all treatment groups at one year. These data highlight the need for high quality clinical trial data to provide evidence-based management of Asian AMD.
Purpose: To assess the diagnostic performance and structure–function association of retinal retardance (RR), a customized metric measured by a prototype polarization-sensitive optical coherence tomography (PS-OCT), across various stages of glaucoma. Methods: This cross-sectional pilot study analyzed 170 eyes from 49 healthy individuals and 68 patients with glaucoma. The patients underwent PS-OCT imaging and conventional spectral-domain optical coherence tomography (SD-OCT), as well as visual field (VF) tests. Parameters including RR and retinal nerve fiber layer thickness (RNFLT) were extracted from identical circumpapillary regions of the fundus. Glaucomatous eyes were categorized into early, moderate, or severe stages based on VF mean deviation (MD). The diagnostic performance of RR and RNFLT in discriminating glaucoma from controls was assessed using receiver operating characteristic (ROC) curves. Correlations among VF-MD, RR, and RNFLT were evaluated and compared within different groups of disease severity. Results: The diagnostic performance of both RR and RNFLT was comparable for glaucoma detection (RR AUC = 0.98, RNFLT AUC = 0.97; P = 0.553). RR showed better structure–function association with VF-MD than RNFLT (RR VF-MD = 0.68, RNFLT VF-MD = 0.58; z = 1.99; P = 0.047) in glaucoma cases, especially in severe glaucoma, where the correlation between VF-MD and RR (r = 0.73) was significantly stronger than with RNFLT (r = 0.43, z = 1.96, P = 0.050). In eyes with early and moderate glaucoma, the structure–function association was similar when using RNFLT and RR. Conclusions: RR and RNFLT have similar performance in glaucoma diagnosis. However, in patients with glaucoma especially severe glaucoma, RR showed a stronger correlation with VF test results. Further research is needed to validate RR as an indicator for severe glaucoma evaluation and to explore the benefits of using PS-OCT in clinical practice. Translational Relevance: We demonstrated that PS-OCT has the potential to evaluate the status of RNFL structural damage in eyes with severe glaucoma, which is currently challenging in clinics.
Abstract Background Myopia affects 1.4 billion individuals worldwide. Notably, there is increasing evidence that choroidal thickness plays an important role in myopia and risk of developing myopia-related conditions. With the advancements in artificial intelligence (AI), choroidal thickness segmentation can now be automated, offering inherent advantages such as better repeatability, reduced grader variability, and less reliance for manpower. Hence, we aimed to evaluate the agreement between AI-automated and manual segmented measurements of subfoveal choroidal thickness (SFCT) using two swept-source optical coherence tomography (OCT) systems. Methods Subjects aged ≥ 16 years, with myopia of ≥ 0.50 diopters in both eyes, were recruited from the Prospective Myopia Cohort Study in Singapore (PROMYSE). OCT scans were acquired using Triton DRI-OCT and PLEX Elite 9000. OCT images were segmented both automatically with an established SA-Net architecture and manually using a standard technique with adjudication by two independent graders. SFCT was subsequently determined based on the segmentation. The Bland–Altman plot and intraclass correlation coefficient (ICC) were used to evaluate the agreement. Results A total of 229 subjects (456 eyes) with mean [± standard deviation (SD)] age of 34.1 (10.4) years were included. The overall SFCT (mean ± SD) based on manual segmentation was 216.9 ± 82.7 µm with Triton DRI-OCT and 239.3 ± 84.3 µm with PLEX Elite 9000. ICC values demonstrated excellent agreement between AI-automated and manual segmented SFCT measurements (PLEX Elite 9000: ICC = 0.937, 95% CI: 0.922 to 0.949, P < 0.001; Triton DRI-OCT: ICC = 0.887, 95% CI: 0.608 to 0.950, P < 0.001). For PLEX Elite 9000, manual segmented measurements were generally thicker when compared to AI-automated segmented measurements, with a fixed bias of 6.3 µm (95% CI: 3.8 to 8.9, P < 0.001) and proportional bias of 0.120 ( P < 0.001). On the other hand, manual segmented measurements were comparatively thinner than AI-automated segmented measurements for Triton DRI-OCT, with a fixed bias of − 26.7 µm (95% CI: − 29.7 to − 23.7, P < 0.001) and proportional bias of − 0.090 ( P < 0.001). Conclusion We observed an excellent agreement in choroidal segmentation measurements when comparing manual with AI-automated techniques, using images from two SS-OCT systems. Given its edge over manual segmentation, automated segmentation may potentially emerge as the primary method of choroidal thickness measurement in the future.
We propose a method for improving the accuracy of the optic cup detected from the ARGALI system. This method makes use of key points from the branching points of large vessels, the analysis of intensity variation and kinks from small vessels to obtain an enhanced optic cup. Measures used to assess the detection of the optic cup showed an 11% and 40% improvement in the mean average overlap and relative area difference respectively over the previous method. The difference in the CDR error was also shown to be reduced to less than 0.1CDR units. The improved optic cup detection is more consistent with the clinical ground truth, facilitating its use in ARGALI for mass screening for glaucoma for early detection to save sight.
Abstract Purpose To assess whether compensating the RNFL thickness for multiple demographic and anatomical factors improves the detection of glaucoma. Methods This case‐control study enrolled 2699 healthy participants to construct and test a multivariate compensation model, which was then applied in 387 healthy controls and 387 glaucoma cases (early, n = 219; moderate, n = 97; and, advanced, n = 71). Participants underwent Cirrus spectral‐domain OCT (Carl Zeiss Meditec) imaging of the optic disc and macular cubes. Compensated RNFL thickness was generated based on ethnicity, age, refractive error, optic disc (ratio, orientation, and area), fovea (distance and angle), and retinal vessel density. RNFL thickness measurements and their corresponding areas under the receiver operating characteristic curves (AUCs) were obtained. Results After applying the Asian‐specific compensation model, the standard deviation (SD) of RNFL thickness reduced, where the effect was greatest for Chinese (16.9%), followed by Malays (13.9%) and then Indians (12.1%). Multivariate normative comparison outperformed measured RNFL for discrimination of early glaucoma (AUC = 0.90 vs 0.85; p < 0.001), moderate glaucoma (AUC = 0.94 vs 0.91; p < 0.001) and advanced glaucoma (AUC = 0.98 vs 0.96; p < 0.001). Conclusions The multivariate normative database of RNFL showed better glaucoma discrimination capability than measured RNFL thickness, which suggests there may be utility in accounting for demographic and anatomical variance in RNFL thickness to improve glaucoma detection.
Abstract Purpose: Diabetes (DM) and hypertension (HTN) are common comorbidities in the elderly and can cause damage to the retina, such as neurodegeneration and vascular impairment. The purpose of this study was to determine the impact of HTN on the axonal versus the vascular components of the RNFL thickness in patients with DM without clinical diabetic retinopathy. Methods: Subjects were divided into three groups: healthy controls, 2. patients with DM only, and 3. patients with both DM and HTN. Automated segmentation of peripapillary RNFL is performed, and vascular component is excluded from the segmented RNFL to obtain the thickness measurements and vascular metrics. RNFL with (original) and without the vascular component (corrected) were compared between subjects with diabetes and healthy controls. Results: A total of 279 eyes were included: 182 eyes in controls group, 31 eyes in DM only, and 66 eyes in DM + HTN. The mean original RNFL thickness was significantly thinner in DM + HTN (−3.85 μm, p = 0.014) when compared to controls (103.9 ± 10.1 μm). This relationship between the groups increased significantly when the vascular component is excluded from the RNFL increased (−4.6 μm, p = 0.002). Retinal vessel density was increased in patients with hypertension (14.83 ± 0.32 μm) versus controls (13.97 ± 0.18 μm, p = 0.019) and was correlated with original RNFL thickness ( r = 0.189, p = 0.001), but not with corrected RNFL ( r = −0.044, p = 0.462). There was no difference in the RNFL thickness between DM only and controls when using either conventional or novel OCT approaches (−3 μm, p ≥ 0.100). Conclusions: The present data indicate that reduced RNFL thickness in diabetic patients without diabetic retinopathy is to a large degree related to impact of hypertension. Changes in peripapillary RNFL thickness as measured with commercial OCT systems may either be the consequence of retinal nerve fibres or reflect changes in retinal vasculature. Accounting for retinal vasculature emphasized the greater decrease in RNFL in HTN individuals than conventional OCT method.
'/%3e%3cuse xlink:href='%23a' transform='translate(288.889 -214.211)'/%3e%3cuse xlink:href='%23a' transform='translate(108 342.749)'/%3e%3cuse xlink:href='%23a' transform='translate(469.189 342.749)'/%3e%3c/svg%3e)
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)