scholarly journals Automated Retinal Boundary Segmentation of Optical Coherence Tomography Images Using an Improved Canny Operator

2021 ◽  
Author(s):  
Jian Liu ◽  
Shixin Yan ◽  
Nan Lu ◽  
Dongni Yang ◽  
Hongyu Lv ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Automatic Segmentation ◽  
Initial Boundary ◽  
Boundary Detection ◽  
Structural Features ◽  
Detection Algorithm ◽  
Age Related Macular Degeneration ◽  
Canny Operator ◽  
Age Related ◽  
Retinal Segmentation

Abstract Retinal segmentation is a prerequisite for quantifying retinal structural features and diagnosing related ophthalmic diseases. Canny operator is recognized as the best boundary detection operator so far, and is often used to obtain the initial boundary of the retina in retinal segmentation. However, the traditional Canny operator is susceptible to vascular shadows, vitreous artifacts, or noise interference in retinal segmentation, causing serious misdetection or missed detection. This paper proposed an improved Canny operator for automatic segmentation of retinal boundaries. The improved algorithm solves the problems of the traditional Canny operator by adding a multi-point boundary search step on the basis of the original method, and adjusts the convolution kernel. The algorithm was used to segment the retinal images of healthy subjects and age-related macular degeneration (AMD) patients; eleven retinal boundaries were identified and compared with the results of manual segmentation by the ophthalmologists. The average difference between the automatic and manual methods is: 2-6 microns (1~2 pixels) for healthy subjects and 3-10 microns (1~3 pixels) for AMD patients. Qualitative method is also used to verify the accuracy and stability of the algorithm. The percentage of “perfect segmentation” and “good segmentation” is 98% in healthy subjects and 94% in AMD patients. This algorithm can be used alone or in combination with other methods as an initial boundary detection algorithm. It is easy to understand and improve, and may become a useful tool for analyzing and diagnosing eye diseases.

Retinal vascular alterations in reticular pseudodrusen with and without outer retinal atrophy assessed by optical coherence tomography angiography

2018 ◽  
Vol 102 (9) ◽  
pp. 1192-1198 ◽  
Author(s):  
Maria Vittoria Cicinelli ◽  
Alessandro Rabiolo ◽  
Riccardo Sacconi ◽  
Francesca Lamanna ◽  
Lea Querques ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Subjects ◽  
Vessel Density ◽  
Age Related Macular Degeneration ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
Reticular Pseudodrusen ◽  
Age Related ◽  
Retinal Atrophy ◽  
Capillary Plexus

PurposeTo investigate the intraretinal structural and vascular alterations in patients featuring reticular pseudodrusen (RPD), RPD with outer retinal atrophy (ORA), and drusen.DesignObservational cross-sectional study.MethodsClinical practice study including 68 eyes of 57 patients (22 eyes of 17 patients with RPD; 24 eyes of 21 patients with RPD+ORA; 22 eyes of 19 patients with drusen). Each patient underwent spectral-domain optical coherence tomography (OCT) and OCT angiography (OCT-A). Measurement of retinal layers’ thickness was obtained by the automated segmentation protocol of the Spectralis OCT (Heidelberg Eye Explorer V.1.9.10.0). The superficial capillary plexus (SCP) and the deep capillary plexus (DCP) vessel density, as well as the size of the foveal avascular zone were calculated on 3×3 OCT-A. Main outcome was to compare vessel density at the SCP and DCP among the groups and controls.ResultsAt the SCP, the vessel density was lower in RPD and RPD+ORA patients with respect to controls (P=0.02 and P=0.003, respectively). At the DCP, meaningful disparity was found between the study groups and the healthy subjects in the vessel density (P<0.001, P=0.04 and P=0.001 for RPD, RDP+ORA and drusen, respectively). The ganglion cell layer (GCL) was thinner in all patients affected either by RPD, RPD+ORA or drusen compared with healthy subjects (P=0.02, P=0.03 and P=0.004, respectively).ConclusionSignificant retinal vascular loss is a common feature of patients with non-exudative age-related macular degeneration, more pronounced in those featuring RPD and RPD+ORA. It is associated with retinal thinning, localised particularly at the GCL, compared with controls.

CLINICAL EVALUATION OF PAZOPANIB EYE DROPS IN HEALTHY SUBJECTS AND IN SUBJECTS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

Retina ◽  
2014 ◽  
Vol 34 (9) ◽  
pp. 1787-1795 ◽  
Author(s):  
Rishi Singh ◽  
John I. Wurzelmann ◽  
Li Ye ◽  
Linda Henderson ◽  
Mohammad Hossain ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Clinical Evaluation ◽  
Healthy Subjects ◽  
Age Related Macular Degeneration ◽  
Eye Drops ◽  
Age Related

Comparison of serum thiol–disulphide homeostasis and total antioxidant–oxidant levels between exudative age-related macular degeneration patients and healthy subjects

2016 ◽  
Vol 37 (5) ◽  
pp. 1095-1101 ◽  
Author(s):  
Ahmet Elbay ◽  
Omer Faruk Ozer ◽  
Julide Canan Umurhan Akkan ◽  
Ugur Celik ◽  
Işıl Kutlutürk ◽  
...  
Keyword(s):  
Macular Degeneration ◽  
Healthy Subjects ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Total Antioxidant

scholarly journals Optical Coherence Tomography Angiography in Retinal Vascular Diseases and Choroidal Neovascularization

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Rodolfo Mastropasqua ◽  
Luca Di Antonio ◽  
Silvio Di Staso ◽  
Luca Agnifili ◽  
Angela Di Gregorio ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Choroidal Neovascularization ◽  
Healthy Subjects ◽  
Optical Coherence Tomography Angiography ◽  
Vascular Diseases ◽  
Age Related Macular Degeneration ◽  
Foveal Avascular Zone ◽  
Optical Coherence ◽  
Age Related ◽  
Split Spectrum

Purpose. To assess the ability of optical coherence tomography-angiography (OCT-A) to show and analyze retinal vascular patterns and the choroidal neovascularization (CNV) in retinal vascular diseases.Methods. Seven eyes of seven consecutive patients with retinal vascular diseases were examined. Two healthy subjects served as controls. All eyes were scanned with the SD-OCT XR Avanti (Optovue Inc, Fremont CA, USA). Split spectrum amplitude decorrelation angiography algorithm was used to identify the blood flow within the tissue. Fluorescein angiography (FA) and indocyanine green angiography (ICGA) with Spectralis HRA + OCT (Heidelberg Engineering GmbH) were performed.Results. In healthy subjects OCT-A visualized major macular vessels and detailed capillary networks around the foveal avascular zone. Patients were affected with myopic CNV (2 eyes), age-related macular degeneration related (2), branch retinal vein occlusion (BRVO) (2), and branch retinal artery occlusion (BRAO) (1). OCT-A images provided distinct vascular patterns, distinguishing perfused and nonperfused areas in BRVO and BRAO and recognizing the presence, location, and size of CNV.Conclusions. OCT-A provides detailed images of retinal vascular plexuses and quantitative data of pathologic structures. Further studies are warranted to define the role of OCT-A in the assessment of retinovascular diseases, with respect to conventional FA and ICG-A.

scholarly journals Automatic segmentation of the borders of the pathological focus in the macular area of the retina to calculate the area of the pathological focus

2021 ◽  
Vol 2131 (2) ◽  
pp. 022081
Author(s):  
V A Filippenko ◽  
U F Bondarenko ◽  
V V Dolgov ◽  
A N Epikhin
Keyword(s):  
Automatic Segmentation ◽  
Correct Diagnosis ◽  
Age Related Macular Degeneration ◽  
Contact Method ◽  
Macular Area ◽  
Cross Sectional ◽  
Human Eye ◽  
Age Related ◽  
Pathological Focus ◽  
Almost All

Abstract Optical coherence tomography (OCT) is a modern, non-contact method of diagnostic examination that enables the visualization of various tissues of the human eye in a cross-sectional view at the microscopic level with the required morphological information. The software pre-installed in such devices contains many different tools for analyzing scans and has almost all the functionality necessary for the doctor to make a correct diagnosis. However, as time passes, more and more advanced methods of analyzing the images appear, which actualizes new tasks of developing additional software that can supplement and expand the functionality of the diagnostic equipment. This paper proposes an algorithm for automatic segmentation of the borders of a pathological focus in the macular area of the retina to calculate the area of the pathological focus, which together with other algorithms for analysis of morphometric parameters of the human eye, which are still under development, will be used for more accurate diagnosis of the stage of age-related macular degeneration.

scholarly journals Choroidal Vascularity Index in Adult-Onset Foveomacular Vitelliform Dystrophy: A Pilot Study

2021 ◽  
Vol 11 (21) ◽  
pp. 10487
Author(s):  
Solmaz Abdolrahimzadeh ◽  
Serena Fragiotta ◽  
Chiara Ciacimino ◽  
Mariachiara Di Pippo ◽  
Gianluca Scuderi
Keyword(s):  
Pilot Study ◽  
Healthy Subjects ◽  
Age Related Macular Degeneration ◽  
Early Age ◽  
Adult Onset ◽  
Age Related ◽  
Luminal Area ◽  
Choroidal Vasculature ◽  
Vascular Status

This pilot study aims to investigate choroidal vascular status in eyes with adult-onset foveomacular vitelliform dystrophy (AOFVD), early age-related macular degeneration (AMD), and age-matched controls. In this retrospective study, choroidal thickness (CT) was measured manually using spectral domain optical coherence tomography images of the fovea, and 500 and 1500 µm from the nasal and temporal regions in the fovea. The horizontal B-scan was imported into Fiji software. Choroidal vascularity index (CVI) and luminal and stromal areas were calculated. A total of 36 eyes from 36 patients, including 18 eyes with AOFVD and 18 eyes with CD, and 16 eyes of healthy subjects were included. CVI was significantly different among subgroups (ANOVA, p = 0.004). Eyes with AOFVD presented a higher CVI (+0.03 ± 0.01, p = 0.001) than eyes with CD and controls (p = 0.03). No differences in CVI were detected between controls and eyes with CD (p = 0.25). AOFVD eyes accounted for the greatest luminal area, particularly significant in comparison with healthy controls (+0.27 ± 0.11, p = 0.02). AOFVD eyes present a greater CVI than eyes with CD and controls. The major choroidal involvement is on the luminal component, further corroborating a possible role of the choroidal vasculature in the pathological manifestations of AOFVD disease.

scholarly journals Scotopic Microperimetry in the Early Diagnosis of Age-Related Macular Degeneration: Preliminary Study

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Marcella Nebbioso ◽  
Andrea Barbato ◽  
Nicola Pescosolido
Keyword(s):  
Early Diagnosis ◽  
Macular Degeneration ◽  
Healthy Subjects ◽  
Age Related Macular Degeneration ◽  
Control Group ◽  
Retinal Sensitivity ◽  
Retinal Diseases ◽  
Age Related ◽  
Preliminary Study ◽  
Fundus Oculi

Background. Recent clinical studies have shown that, in some degenerative retinal diseases, like age-related macular degeneration (AMD), the sensitivity of the rods decreases more rapidly than the sensitivity of the cones. The aim of this study was to evaluate if there is a correlation between the presence of hard drusen at the macular level and the rod damage responsible for the reduction in scotopic retinal sensitivity in subjects at risk for AMD.Methods. The authors selected 24 subjects (14 men and 10 women) with an average age of 67.25 ± 5.7 years. Macular hard drusen were present in 50% of the subjects at thefundus oculiexam. The researchers evaluated the retinal sensitivity to light in mesopic and scotopic conditions of each subject with an MP-1 scotopic microperimeter (MP-1S).Results. In subjects with hard drusen in thefundus oculiexamination, there was a statistically significant reduction in scotopic retinal sensitivity, while the mesopic retinal sensitivity was not compromised.Conclusion. This study revealed how the presence of hard drusen at the macular level is associated with a reduction in scotopic retinal sensitivity compared to a control group of healthy subjects. Retinal functionality in a scotopic setting examined with MP-1S could be useful in early diagnosis of AMD.

scholarly journals Serum 25-hydroxy vitamin D levels in age-related macular degeneration

2021 ◽  
Author(s):  
Antonio Pérez Serena ◽  
Daisy Paola Martínez Betancourt ◽  
Fernando González del Valle ◽  
Jose María Ruiz Moreno
Keyword(s):  
Vitamin D ◽  
Macular Degeneration ◽  
Healthy Subjects ◽  
Age Related Macular Degeneration ◽  
Fundus Photography ◽  
Control Group ◽  
Neovascular Amd ◽  
Age Related ◽  
Vitamin D Levels ◽  
25 Hydroxy Vitamin D

Abstract Purpose The aim of this study was to determine the 25-hydroxy vitamin D (25(OH)D) levels in age-related macular degeneration (AMD) patients. Methods Age-related macular degeneration (AMD) patients were classified into four groups: early AMD (N =10), intermediate AMD (N=12), advanced atrophic AMD (N=19) and advanced neovascular AMD (N=52) after undergoing fundus photography. Serum 25(OH)D levels of all subjects were evaluated. From a random control group of 326 patients whose 25(OH)D levels had been measured, a group of 93 were selected to match the age range of the AMD group. We measured 25(OH)D levels during the same period to rule out seasonal variation. Results A total of 93 AMD patients (36 males and 57 females) and 93 healthy individuals (39 males and 54 females) were enrolled in this study with the mean age of 78.96±8.46 vs. 78.80±8.35, respectively. The patients affected by AMD had statistically significant lower 25(OH)D levels (15±10 ng/mL) than the healthy subjects control group (21±14 ng/mL) (p = 0.004). However, the median 25(OH)D levels in early AMD, intermediate AMD, advanced atrophic AMD and advanced neovascular AMD (12.5±7.3; 15±11; 15±8 and 17±11.5, respectively) were not statistically significant (p = 0.442). Conclusion This study shows that patients affected by AMD had lower vitamin D levels compared to healthy subjects. Further research is necessary to investigate the possible association between 25(OH)D levels and AMD.

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