CLINICAL OUTCOMES OF ACUTE ENDOPHTHALMITIS AFTER INTRAVITREAL DELIVERY OF VASCULAR ENDOTHELIAL GROWTH FACTOR INHIBITORS VERSUS STEROIDS.

PURPOSE: To compare patients with acute endophthalmitis after intravitreal injection of vascular endothelial growth factor (VEGF) inhibitors vs. steroids. METHODS: Retrospective single-center, nonrandomized interventional study from 2013 to 2021.Patients underwent vitreous biopsy before initiating treatment and were divided into the following cohorts: (1) anti-VEGF managed medically (T&I-anti-VEGF), (2) anti-VEGF managed by immediate pars plana vitrectomy (PPV-anti-VEGF), and (3) steroid therapy and managed medically or by pars plana vitrectomy (steroid). RESULTS: A total of 141 patients were analyzed. The steroid cohort demonstrated significantly worse presenting (median = 2.80 logarithm of the minimum angle of resolution [logMAR]; P ≤ 0.01) and final (median = 2.30 logMAR) best-corrected visual acuity compared with T&I-anti-VEGF (presenting: median = 2.00 logMAR; final: median = 0.40 logMAR) and pars plana vitrectomy-anti-VEGF cohorts (presenting: median = 2.30 logMAR; final: median = 0.48 logMAR). There was no significant ( P = 0.33) difference in the final best-corrected visual acuity between T&I-anti-VEGF and pars plana vitrectomy-anti-VEGF cohorts. There were no significant ( P ≥ 0.63) differences among cohorts in best-corrected visual acuity before acute endophthalmitis diagnosis (T&I-anti-VEGF: median = 0.40 logMAR; pars plana vitrectomy-anti-VEGF: median = 0.40 logMAR; steroid: median = 0.44 logMAR). Microbial cultures revealed similar profiles for all cohorts. CONCLUSION: Acute endophthalmitis after intravitreal injection steroid therapy had worse outcomes compared with anti-VEGF therapy.

CHOROIDAL NEVUS ASSOCIATED WITH VITELLIFORM DEPOSITION IN A PATIENT WITH AUTOSOMAL DOMINANT BEST DYSTROPHY.

BACKGROUND/PURPOSE: To describe the clinical, optical coherence tomography (OCT), fundus autofluorescence and ultrasound findings of a patient with a choroidal nevus actively exuding vitelliform material in the setting of autosomal dominant Best dystrophy (BD). METHODS: The patient's clinical course was followed over time with ophthalmic examinations and multimodal imaging. RESULTS: A 71-year-old male patient with BD was referred for evaluation of a choroidal nevus in the right eye. Dilated fundoscopic examination showed a small pigmented choroidal nevus in the temporal periphery. Over a 3-year period, the nevus developed progressive deposition of vitelliform material along its inferior border. Meanwhile, OCT and fundus photography showed only slight growth. Ultrasound showed no change in height; basal measurements were confounded by the increased vitelliform deposits. Genetic testing confirmed a heterozygous mutation in the BEST1 gene and electrophysiology was consistent with BD. CONCLUSIONS: Dysfunction of the retinal pigment epithelium associated with BD may cause novel presentations of other conditions such as choroidal nevi. The implication for malignant transformation of a choroidal nevus associated with vitelliform deposit accumulation in this context is unknown.

Radiation and systemic immunotherapy for metastatic uveal melanoma: a clinical retrospective review.

Introduction: Metastatic uveal melanoma (mUM) is a difficult to treat disease. The liver is the primary site of metastasis in most patients, though uveal melanoma spreads widely in advanced disease. The only FDA approved immunotherapy medication for metastatic uveal melanoma is the HLA-A02:01 restricted bispecific T cell engager drug, Tebentafusp. Checkpoint inhibitor strategies and combination approaches have been tried with some limited success. We describe our experience treating patients at the University of Minnesota. Methods: Patients were included if they had biopsy-confirmed mUM. Twenty-five (25) patients meeting the criteria were identified. Medical records were reviewed and data extracted for patient baseline characteristics and response to treatments. Results: Median time to metastasis from the time of local therapy to the eye was 14.2 months (IQR; 9.3-22.0), and first site of metastasis was liver in 92% of patients. Two patients (8%) did not receive systemic therapy or radiation therapy for metastatic disease. Twenty-three (92%) patients received systemic therapy, 13 patients (52%) received ipilimumab-nivolumab as the first-line, while 4 patients (16%) received pembrolizumab. Landmark survival analysis by receipt of systemic therapy and radiation therapy treatments within 6 months of biopsy confirmed diagnosis is shown. Twenty patients (80%) received systemic therapy within 6 months of mUM diagnosis. Thirteen patients (52%) received liver directed radiation therapy within 6 months of mUM diagnosis. Discussion: Within our cohort, there was no overall survival benefit for patients receiving treatment of metastatic disease within 6 months of mUM diagnosis, versus those electing later or no treatment at all. There was remarkable clinical activity of ipilimumab and nivolumab in a subset of patients with mUM, in agreement with prior studies, and metastatic PD-L1 positive tumors were associated with a prolonged survival.

Sustained Control of Serpiginous Choroiditis with the Fluocinolone Acetonide 0.18 mg Intravitreal Implant.

Purpose: To describe an alternative treatment for a patient with serpiginous choroiditis (SC) who was not tolerant to systemic therapies. Methods: Case report of a patient with serpiginous choroiditis with their clinical course followed with ophthalmic examinations and multimodal imaging overtime. Patients and Results. A 57-year-old female with serpiginous choroiditis was treated for seven years with numerous therapies including systemic steroids, immunosuppressive agents, and repeated dexamethasone intravitreal implants. The patient was intolerant of systemic therapies and would flare if dexamethasone injections were performed less frequently than every 8 weeks, making a viable long-term treatment plan problematic. Following one injection of the fluocinolone acetonide 0.18 mg intravitreal implant, she has experienced sustained control for 20 months. Discussion and Conclusions. Real-world treatment of SC is complex as long-term control is necessary, and associated side effects of the therapies provided may limit sustained use. The fluocinolone acetonide implant lasts 36 months and may be an alternative long-term management option, especially in the setting of systemic medication intolerance for some patients with SC.

Short term visual and structural outcomes of anti-vascular endothelial growth factor (anti-VEGF) treatment delay during the first COVID-19 wave: A pilot study.

Regularly scheduled intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections are essential to maintaining and/or improving many ocular conditions including: neovascular age-related macular degeneration (nAMD), diabetic retinopathy, and retinal vein occlusions with macular edema (RVO). This study aims to assess the effect of unintended delays in anti-VEGF treatment during the first wave of the COVID-19 pandemic. This retrospective case series identified patients receiving regularly scheduled anti-VEGF intravitreal injections based on current procedural terminology (CPT) code at two practices in Minnesota. Diagnoses were limited to nAMD, diabetic macular edema (DME), proliferative diabetic retinopathy, and RVO. Patients were divided into two groups based on whether they maintained or delayed their follow-up visit by more than two weeks beyond the recommended treatment interval during the COVID-19 lockdown. The 'COVID-19 lockdown' was defined as the period after March, 28th, 2020, when a lockdown was declared in Minnesota. We then compared the visual acuity and structural changes to the retina using ocular coherence tomography (OCT) to assess whether delayed treatment resulted in worse visual outcomes. A total of 167 eyes from 117 patients met criteria for inclusion in this study. In the delayed group, the average BCVA at the pre- and post-lockdown visits were 0.614 and 0.715 (logMAR) respectively (p = 0.007). Central subfield thickness (CST) increased from 341 to 447 in the DME delayed group (p = 0.03) while the CST increased from 301 to 314 (p = 0.4) in the nAMD delayed group. The results of this pilot study suggests that treatment delays may have a negative impact on the visual and anatomic outcomes of patients with nAMD and DME. Future studies with larger sample sizes are required for further investigation.

Hemifacial Spasm in an Argus II Retinal Prosthesis Patient.

Purpose: A 59-year-old man with retinitis pigmentosa, who received an Argus II retinal prosthesis in the left eye 3 years prior, presented with left-sided involuntary facial contractions that occurred only after turning on the Argus II device. Methods: A case report. Results: Given that this patient's reported and visualized lower eyelid twitching corresponds to the location of the external region of the implanted coil, we hypothesize that heat or wirelessly transmitted electrical signals from the external coil to the implanted coil may induce spasm of the facial nerve and thus play a role in hemifacial spasm onset. Conclusions: To our knowledge, this is the first report of hemifacial spasm associated with Argus II use.

Comparing fundus autofluorescence and infrared imaging findings of peripheral retinoschisis, schisis detachment, and retinal detachment.

PURPOSE: The primary goal of this study was to identify characteristic features of peripheral degenerative retinoschisis (RS), schisis detachment (SD) and retinal detachment (RD) on both fundus autofluorescence (FAF) and infrared (IR) imaging, using spectral domain optical coherence tomography (SD-OCT) imaging of the peripheral retina as the confirmatory imaging tool. METHODS: This is a descriptive case series study. A total of 27 eyes of 22 patients were included. Thirteen eyes of 10 patients diagnosed with RS, 4 eyes of 3 patients diagnosed with SD, and 10 eyes of 9 patients diagnosed with RD were included. Patients with images of poor quality were excluded. Heidelberg Spectralis HRA + OCT machine (Heidelberg Engineering, Heidelberg, Germany) were used to acquire the images. RESULTS: All conditions appeared as areas of hypo-AF on FAF and hypo-reflectance on IR imaging. Accentuated vasculature of the lesion was noted with IR imaging due to elevation of the RS and RD, which was less frequently observed with FAF. On FAF, a hyper-AF leading edge around the RS lesion indicated the presence of intraretinal or subretinal fluid and an extension of the RS. Retinal breaks/holes were best visualized with IR imaging. SD-OCT confirmed the diagnosis in all performed cases. CONCLUSIONS: We were unable to differentiate between RS and RD based solely on findings from FAF and IR imaging. However, the combination of them with SD-OCT can assist in the diagnosis of RS from RD and in the evaluation of RS progression. OCT remains the main modality imaging to differentiate these conditions.

Phenotypic heterogeneity and lesion size measurements in Stargardt macular dystrophy.

Fundus autofluorescence has been used in Stargardt macular dystrophy and fundus flavimaculatus to better understand disease status and progression. Fundus autofluorescence images delineate atrophic regions with great clarity and high contrast. The authors investigated whether fundus autofluorescence images revealed more atrophy than color fundus photographs by studying a family of three siblings with long-standing disease that demonstrated a heterogeneous fundus appearance. Findings on fundus autofluorescence were compared with color fundus photographs and fluorescein images. Optical coherence tomography images were also analyzed. Areas of atrophic lesions were measured and compared on fundus autofluorescence and color fundus photographs. Autofluorescence images delineated atrophic regions more clearly than color fundus photographs. However, the measured areas of atrophy were only modestly larger in fundus autofluorescence images than in color fundus photographs. The optical coherence tomography images showed severe outer retinal atrophy and loss of foveal contour.

RETOUCH: The Retinal OCT Fluid Detection and Segmentation Benchmark and Challenge.

Retinal swelling due to the accumulation of fluid is associated with the most vision-threatening retinal diseases. Optical coherence tomography (OCT) is the current standard of care in assessing the presence and quantity of retinal fluid and image-guided treatment management. Deep learning methods have made their impact across medical imaging, and many retinal OCT analysis methods have been proposed. However, it is currently not clear how successful they are in interpreting the retinal fluid on OCT, which is due to the lack of standardized benchmarks. To address this, we organized a challenge RETOUCH in conjunction with MICCAI 2017, with eight teams participating. The challenge consisted of two tasks: fluid detection and fluid segmentation. It featured for the first time: all three retinal fluid types, with annotated images provided by two clinical centers, which were acquired with the three most common OCT device vendors from patients with two different retinal diseases. The analysis revealed that in the detection task, the performance on the automated fluid detection was within the inter-grader variability. However, in the segmentation task, fusing the automated methods produced segmentations that were superior to all individual methods, indicating the need for further improvements in the segmentation performance.

OCT Fluid Segmentation using Graph Shortest Path and Convolutional Neural Network.

Diagnosis and monitoring of retina diseases related to pathologies such as accumulated fluid can be performed using optical coherence tomography (OCT). OCT acquires a series of 2D slices (Bscans). This work presents a fully-automated method based on graph shortest path algorithms and convolutional neural network (CNN) to segment and detect three types of fluid including sub-retinal fluid (SRF), intra-retinal fluid (IRF) and pigment epithelium detachment (PED) in OCT Bscans of subjects with age-related macular degeneration (AMD) and retinal vein occlusion (RVO) or diabetic retinopathy. The proposed method achieves an average dice coefficient of 76.44%, 92.25% and 82.14% in Cirrus, Spectralis and Topcon datasets, respectively. The effectiveness of the proposed methods was also demonstrated in segmenting fluid in OCT images from the 2017 Retouch challenge.

Association of Optic Nerve Head Drusen with Best Vitelliform Macular Dystrophy: A Case Series.

PURPOSE: To report the association of optic nerve head (ONH) drusen with Best vitelliform macular dystrophy (BVMD). METHODS: Chart review. PATIENTS: Five patients from 3 families. RESULTS: Multimodal imaging and ophthalmic examination demonstrated findings consistent with ONH drusen, in association with BVMD, in 5 patients. CONCLUSION: We report the association of BVMD with ONH drusen in 5 patients. This combination has previously been reported only once. We recommend that patients with a diagnosis of BVMD undergo autofluorescence and ultrasound imaging of the optic nerve to help facilitate this diagnosis, as some ONH drusen can be buried.

Fully Automated Segmentation of Fluid/Cyst Regions in Optical Coherence Tomography Images With Diabetic Macular Edema Using Neutrosophic Sets and Graph Algorithms.

This paper presents a fully automated algorithm to segment fluid-associated (fluid-filled) and cyst regions in optical coherence tomography (OCT) retina images of subjects with diabetic macular edema. The OCT image is segmented using a novel neutrosophic transformation and a graph-based shortest path method. In neutrosophic domain, an image is transformed into three sets: (true), (indeterminate) that represents noise, and (false). This paper makes four key contributions. First, a new method is introduced to compute the indeterminacy set , and a new -correction operation is introduced to compute the set in neutrosophic domain. Second, a graph shortest-path method is applied in neutrosophic domain to segment the inner limiting membrane and the retinal pigment epithelium as regions of interest (ROI) and outer plexiform layer and inner segment myeloid as middle layers using a novel definition of the edge weights . Third, a new cost function for cluster-based fluid/cyst segmentation in ROI is presented which also includes a novel approach in estimating the number of clusters in an automated manner. Fourth, the final fluid regions are achieved by ignoring very small regions and the regions between middle layers. The proposed method is evaluated using two publicly available datasets: Duke, Optima, and a third local dataset from the UMN clinic which is available online. The proposed algorithm outperforms the previously proposed Duke algorithm by 8% with respect to the dice coefficient and by 5% with respect to precision on the Duke dataset, while achieving about the same sensitivity. Also, the proposed algorithm outperforms a prior method for Optima dataset by 6%, 22%, and 23% with respect to the dice coefficient, sensitivity, and precision, respectively. Finally, the proposed algorithm also achieves sensitivity of 67.3%, 88.8%, and 76.7%, for the Duke, Optima, and the university of minnesota (UMN) datasets, respectively.

Fully-automated segmentation of fluid regions in exudative age-related macular degeneration subjects: Kernel graph cut in neutrosophic domain.

A fully-automated method based on graph shortest path, graph cut and neutrosophic (NS) sets is presented for fluid segmentation in OCT volumes for exudative age related macular degeneration (EAMD) subjects. The proposed method includes three main steps: 1) The inner limiting membrane (ILM) and the retinal pigment epithelium (RPE) layers are segmented using proposed methods based on graph shortest path in NS domain. A flattened RPE boundary is calculated such that all three types of fluid regions, intra-retinal, sub-retinal and sub-RPE, are located above it. 2) Seed points for fluid (object) and tissue (background) are initialized for graph cut by the proposed automated method. 3) A new cost function is proposed in kernel space, and is minimized with max-flow/min-cut algorithms, leading to a binary segmentation. Important properties of the proposed steps are proven and quantitative performance of each step is analyzed separately. The proposed method is evaluated using a publicly available dataset referred as Optima and a local dataset from the UMN clinic. For fluid segmentation in 2D individual slices, the proposed method outperforms the previously proposed methods by 18%, 21% with respect to the dice coefficient and sensitivity, respectively, on the Optima dataset, and by 16%, 11% and 12% with respect to the dice coefficient, sensitivity and precision, respectively, on the local UMN dataset. Finally, for 3D fluid volume segmentation, the proposed method achieves true positive rate (TPR) and false positive rate (FPR) of 90% and 0.74%, respectively, with a correlation of 95% between automated and expert manual segmentations using linear regression analysis.

Automated detection of neovascularization for proliferative diabetic retinopathy screening.

Neovascularization is the primary manifestation of proliferative diabetic retinopathy (PDR) that can lead to acquired blindness. This paper presents a novel method that classifies neovascularizations in the 1-optic disc (OD) diameter region (NVD) and elsewhere (NVE) separately to achieve low false positive rates of neovascularization classification. First, the OD region and blood vessels are extracted. Next, the major blood vessel segments in the 1-OD diameter region are classified for NVD, and minor blood vessel segments elsewhere are classified for NVE. For NVD and NVE classifications, optimal region-based feature sets of 10 and 6 features, respectively, are used. The proposed method achieves classification sensitivity, specificity and accuracy for NVD and NVE of 74%, 98.2%, 87.6%, and 61%, 97.5%, 92.1%, respectively. Also, the proposed method achieves 86.4% sensitivity and 76% specificity for screening images with PDR from public and local data sets. Thus, the proposed NVD and NVE detection methods can play a key role in automated screening and prioritization of patients with diabetic retinopathy.

Optic Disc Boundary and Vessel Origin Segmentation of Fundus Images.

This paper presents a novel classification-based optic disc (OD) segmentation algorithm that detects the OD boundary and the location of vessel origin (VO) pixel. First, the green plane of each fundus image is resized and morphologically reconstructed using a circular structuring element. Bright regions are then extracted from the morphologically reconstructed image that lie in close vicinity of the major blood vessels. Next, the bright regions are classified as bright probable OD regions and non-OD regions using six region-based features and a Gaussian mixture model classifier. The classified bright probable OD region with maximum Vessel-Sum and Solidity is detected as the best candidate region for the OD. Other bright probable OD regions within 1-disc diameter from the centroid of the best candidate OD region are then detected as remaining candidate regions for the OD. A convex hull containing all the candidate OD regions is then estimated, and a best-fit ellipse across the convex hull becomes the segmented OD boundary. Finally, the centroid of major blood vessels within the segmented OD boundary is detected as the VO pixel location. The proposed algorithm has low computation time complexity and it is robust to variations in image illumination, imaging angles, and retinal abnormalities. This algorithm achieves 98.8%-100% OD segmentation success and OD segmentation overlap score in the range of 72%-84% on images from the six public datasets of DRIVE, DIARETDB1, DIARETDB0, CHASE_DB1, MESSIDOR, and STARE in less than 2.14 s per image. Thus, the proposed algorithm can be used for automated detection of retinal pathologies, such as glaucoma, diabetic retinopathy, and maculopathy.

Artery/vein classification of retinal blood vessels using feature selection.

Automated classification of retinal vessels in fundus images is the first step towards measurement of retinal characteristics that can be used to screen and diagnose vessel abnormalities for cardiovascular and retinal disorders. This paper presents a novel approach to vessel classification to compute the artery/vein ratio (AVR) for all blood vessel segments in the fundus image. The features extracted are then subjected to a selection procedure using Random Forests (RF) where the features that contribute most to classification accuracy are chosen as input to a polynomial kernel Support Vector Machine (SVM) classifier. The most dominant feature was found to be the vessel information obtained from the Light plane of the LAB color space. The SVM is then subjected to one time training using 10-fold cross validation on images randomly selected from the VICAVR dataset before testing on an independent test dataset, derived from the same database. An Area Under the ROC Curve (AUC) of 97.2% was obtained on an average of 100 runs of the algorithm. The proposed algorithm is robust due to the feature selection procedure, and it is possible to get similar accuracies across many datasets.

Implantation of the Argus II Retinal Prosthesis in an Eye With Short Axial Length.

The authors describe the implantation of the Argus II Retinal Prosthesis System (Argus II) (Second Sight Medical Products, Sylmar, CA) into a short axial length (AL) eye. The authors' main modification is the use of endocyclophotocoagulation (endo-CPC) to the ciliary processes in the area that the cable enters through the sclerotomy. This case describes the surgical technique necessary for successful implantation of the Argus II into a short AL eye. The use of endo-PC prevents chafing to the ciliary processes, does not affect postoperative intraocular pressure, and facilitates direct visualization of the structures during the surgery, preventing damage during implantation.

The Effect of Scleral Buckling Surgery on Choroidal Thickness Measured by Enhanced Depth Optical Coherence Tomography: A Cross-Sectional Study.

INTRODUCTION: To assess the anatomical changes taking place in the choroid after a scleral buckle (SB) procedure for retinal detachment repair. METHODS: This cross-sectional study looked at 23 adults with a history of unilateral retinal detachment repaired with a SB or other encircling element. The subjects underwent bilateral Enhanced Depth Spectral Domain Optical Coherence Tomography to image the choroid. The choroidal thickness (CT) was measured, and the non-operative eye was used as an internal control. RESULTS: CT was measured to be 170.8 ± 60.9 µm (mean ± SD) in eyes with SBs compared to 175.1 ± 61.9 µm in non-operative eyes. There was no statistically significant difference between the two groups (mean 4.3 µm, 95% CI -8.7, 17.3, p value 0.4973, paired t test). CONCLUSION: Placement of an SB as part of a surgery to repair retinal detachment did not significantly alter CT at the macula.

Strategies for Improving Patient Comfort During Intravitreal Injections: Results from a Survey-Based Study.

INTRODUCTION: Many ocular diseases require intravitreal injections of pharmacological agents. Optimizing patients' experiences during injections is important to ensure compliance and maintenance of quality of life. The objective of this study was to identify strategies to help alleviate discomfort during intravitreal injections. METHODS: A cross-sectional study surveying 128 patients during clinic visits between 2014 and 2015 in two outpatient Retina Clinics (one academic and one private). Patients receiving an intravitreal injection(s) for any retinal disorder were given a questionnaire with 10-yes/no responses for various potential strategies. Responses were stratified by sex, age (<30 years, 30-60 years, and >60 years) and total number of prior injections (0-9 injections, 10-20 injections and >20 injections). RESULTS: A total of 128 patients were surveyed: 59 males, 41 females and 28 with no sex specified. Our results identified four favorable strategies as those receiving more than 50% "yes" votes. These included the presence of technician/staff during the procedure, the use of a neck pillow, a verbal warning before the injection and performing injections in both eyes on the same day. Other specific strategies were identified for females, younger patients and those with greatest experience. These included: females preferred having their hand held during injections (P = 0.001) and using a stress ball (P = 0.000) when compared to males. Stratifying by age, patients 30-60 years old preferred having their hand held (P = 0.008) and background music (P = 0.007). Stratifying by prior injections, patients with >20 prior injections preferred having their hand held (P = 0.001), using a stress ball (P = 0.021) and, if necessary, having bilateral injections performed the same day to improve comfort (P = 0.037). CONCLUSIONS: Having an extra staff member present during the injection, having a neck pillow, having a verbal warning prior to injection and having both eyes injected on the same day were indicated as favorable strategies by over half of those surveyed. Further, specific strategies were identified for females, younger patients (30-60 years old) and those with greatest experience (>20 injections).

Iterative Vessel Segmentation of Fundus Images.

This paper presents a novel unsupervised iterative blood vessel segmentation algorithm using fundus images. First, a vessel enhanced image is generated by tophat reconstruction of the negative green plane image. An initial estimate of the segmented vasculature is extracted by global thresholding the vessel enhanced image. Next, new vessel pixels are identified iteratively by adaptive thresholding of the residual image generated by masking out the existing segmented vessel estimate from the vessel enhanced image. The new vessel pixels are, then, region grown into the existing vessel, thereby resulting in an iterative enhancement of the segmented vessel structure. As the iterations progress, the number of false edge pixels identified as new vessel pixels increases compared to the number of actual vessel pixels. A key contribution of this paper is a novel stopping criterion that terminates the iterative process leading to higher vessel segmentation accuracy. This iterative algorithm is robust to the rate of new vessel pixel addition since it achieves 93.2-95.35% vessel segmentation accuracy with 0.9577-0.9638 area under ROC curve (AUC) on abnormal retinal images from the STARE dataset. The proposed algorithm is computationally efficient and consistent in vessel segmentation performance for retinal images with variations due to pathology, uneven illumination, pigmentation, and fields of view since it achieves a vessel segmentation accuracy of about 95% in an average time of 2.45, 3.95, and 8 s on images from three public datasets DRIVE, STARE, and CHASE_DB1, respectively. Additionally, the proposed algorithm has more than 90% segmentation accuracy for segmenting peripapillary blood vessels in the images from the DRIVE and CHASE_DB1 datasets.