scholarly journals Macular Hole Detection Using a New Hybrid Method: Using Multilevel Thresholding and Derivation on Optical Coherence Tomographic Images

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Sahand Shahalinejad ◽  
Reza Seifi Majdar
Keyword(s):  
Feature Extraction ◽  
Macular Hole ◽  
Vision Loss ◽  
Multistep Method ◽  
Optical Coherence ◽  
Multilevel Thresholding ◽  
Data Set ◽  
Tomographic Images ◽  
Macular Holes ◽  
Novel Method

Optical coherence tomography (OCT) is a noninvasive imaging test. OCT imaging is analogous to ultrasound imaging, except that it uses light instead of sound. In this type of image, microscopic quality intratissue images are provided. In addition, fast and direct imaging of tissue morphology and reproducibility of results are the advantages of this imaging. Macular holes are a common eye disease that leads to visual impairment. The macular perforation is a rupture in the central part of the retina that, if left untreated, can lead to vision loss. A novel method for detecting macular holes using OCT images based on multilevel thresholding and derivation is proposed in this paper. This is a multistep method, which consists of segmentation, feature extraction, and feature selection. A combination of thresholding and derivation is used to diagnose the macular hole. After feature extraction, the features with useful information are selected and finally the output image of the macular hole is obtained. An open-access data set of 200 images with the size of 224 × 224 pixels from Sankara Nethralaya (SN) Eye Hospital, Chennai, India, is used in the experiments. Experimental results show better-diagnosing results than some recent diagnosing methods.

scholarly journals Optical Coherence Tomography Findings in Idiopathic Macular Holes

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Lynn L. Huang ◽  
David H. Levinson ◽  
Jonathan P. Levine ◽  
Umar Mian ◽  
Irena Tsui
Keyword(s):  
Optical Coherence Tomography ◽  
Macular Hole ◽  
Clinical Assessment ◽  
Chart Review ◽  
Subretinal Fluid ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Macular Holes ◽  
Idiopathic Macular Holes ◽  
Intraretinal Cysts

Purpose. To describe the characteristics of idiopathic macular holes (MH) on optical coherence tomography (OCT) and correlate OCT with clinical assessment.Design. Cross-sectional chart review and OCT assessment.Participants. Sixty-seven eyes with a clinically diagnosed idiopathic MH with available OCT data.Methods. A retrospective chart review and OCT assessment.Results. Based on OCT grading, 40 eyes had a full-thickness macular hole (FTMH) and 21 eyes had a lamellar macular hole (LMH). Clinical exam and OCT assessment agreed in 53 (87%) eyes when assessing the extent of MH. Six eyes (14.6%) in the FTMH group, and 3 eyes in the LMH group (14.3%) had persistent vitreomacular traction. Thirty-seven eyes (92.5%) in the FTMH group and 11 eyes (52.4%) in the LMH group had associated intraretinal cysts. Two eyes (5.0%) in the FTMH group and zero eyes in the LMH group had subretinal fluid. Intraretinal cysts were found to be more frequently associated with FTMH than with LMH (P<0.001).Conclusion. This paper described OCT findings in a group of patients with clinically diagnosed MH. A high level of correlation between clinical assessment and OCT findings of LMH and FTMH was observed, and intraretinal cysts were often present in FTMH.

Morphofunctional analysis of the retina in the surgical treatment of idiopathic macular holes

2021 ◽  
pp. 48-52
Author(s):  
A.S. Zotov ◽  
◽  
A.S. Balalin ◽  
S.V. Balalin ◽  
S.M. Purshak ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Surgical Treatment ◽  
Macular Hole ◽  
Practical Importance ◽  
Functional Results ◽  
Hole Diameter ◽  
Optical Coherence ◽  
Macular Holes ◽  
Idiopathic Macular Holes ◽  
Morphofunctional Analysis

Purpose. To evaluate the role of microperimetry and optical coherence tomography (OCT) in the morphofunctional analysis of the retina after surgical treatment of idiopathic macular holes (IMH). Materials and methods. A retrospective study of 33 patient's treatment results (33 eyes) with IMH was carried out. All patients underwent minimally invasive with 25G or 27G vitrectomy. Best corrected visual acuity (BCVA), macular photosensitivity, fixation stability, macular neuroepithelial (NE) volume and minimal macular hole diameter were analyzed. Follow-up period: 6 months. Results. A complete closure of the macular hole was achieved in all cases post-op. The patients had reliable improvement of BCVA, retinal photosensitivity and decrease of macular NE volume. Based on a multifactor correlation analysis with the purpose to predict the results of surgical treatment, the dependence of post-op BCVA on the pre-op photosensitivity of the retina and the minimal diameter of the macular hole was revealed. Conclusions. Microperimetry and OCT are modern non-invasive research methods allowing to estimate anatomical and functional results of surgical IMH treatment. The study of retinal photosensitivity in the macula and minimal macular hole diameter pre-op allows to predict post-op BCVA, which has a practical importance. Keywords: idiopathic macular hole, vitrectomy, microperimetry, optical coherence tomography.

scholarly journals Density-based classification in diabetic retinopathy through thickness of retinal layers from optical coherence tomography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shariq Mohammed ◽  
Tingyang Li ◽  
Xing D. Chen ◽  
Elisa Warner ◽  
Anand Shankar ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diabetic Retinopathy ◽  
Predictive Power ◽  
Vision Loss ◽  
Plexiform Layer ◽  
Retinal Layer ◽  
Optical Coherence ◽  
Summary Statistics ◽  
Data Set ◽  
Retinal Layers

Abstract Diabetic retinopathy (DR) is a severe retinal disorder that can lead to vision loss, however, its underlying mechanism has not been fully understood. Previous studies have taken advantage of Optical Coherence Tomography (OCT) and shown that the thickness of individual retinal layers are affected in patients with DR. However, most studies analyzed the thickness by calculating summary statistics from retinal thickness maps of the macula region. This study aims to apply a density function-based statistical framework to the thickness data obtained through OCT, and to compare the predictive power of various retinal layers to assess the severity of DR. We used a prototype data set of 107 subjects which are comprised of 38 non-proliferative DR (NPDR), 28 without DR (NoDR), and 41 controls. Based on the thickness profiles, we constructed novel features which capture the variation in the distribution of the pixel-wise retinal layer thicknesses from OCT. We quantified the predictive power of each of the retinal layers to distinguish between all three pairwise comparisons of the severity in DR (NoDR vs NPDR, controls vs NPDR, and controls vs NoDR). When applied to this preliminary DR data set, our density-based method demonstrated better predictive results compared with simple summary statistics. Furthermore, our results indicate considerable differences in retinal layer structuring based on the severity of DR. We found that: (a) the outer plexiform layer is the most discriminative layer for classifying NoDR vs NPDR; (b) the outer plexiform, inner nuclear and ganglion cell layers are the strongest biomarkers for discriminating controls from NPDR; and (c) the inner nuclear layer distinguishes best between controls and NoDR.

scholarly journals Autologous Platelet-Rich Fibrin in the Treatment of Refractory Macular Holes

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Arif Koytak ◽  
Fadime Nuhoglu ◽  
Havvanur Bayraktar ◽  
Rukiye Ercan ◽  
Hakan Ozdemir
Keyword(s):  
Macular Hole ◽  
Sulfur Hexafluoride ◽  
Case Reports ◽  
Effective Alternative ◽  
Platelet Rich Fibrin ◽  
Gas Tamponade ◽  
First Case ◽  
Macular Holes ◽  
Novel Method ◽  
Autologous Platelet

Purpose. To describe a novel method for the treatment of refractory macular holes. Methods. Two case reports on the use of autologous platelet rich fibrin (PRF), followed by sulfur hexafluoride gas tamponade to facilitate closure of refractory macular holes. Results. Macular holes were succesfully closed within a week in both cases. Best corrected Snellen visual acuities improved from counting fingers to 0.16 in the first case, and from 0.05 to 0.2 in the second case. No complication occurred during or after the procedures. Conclusion. The use of autologous PRF seems to be a safe and effective alternative method for the treatment of refractory macular holes. Further experience and studies are required to assess the value of autologous PRF in the management of challenging macular hole cases of different etiologies. To the best of our knowledge, this is the first use of autologous PRF in the treatment of macular holes.

Foveal Microstructure on Spectral-Domain Optical Coherence Tomographic Images and Visual Function After Macular Hole Surgery

2011 ◽  
Vol 152 (2) ◽  
pp. 283-290.e1 ◽  
Author(s):  
Emi Ooka ◽  
Yoshinori Mitamura ◽  
Takayuki Baba ◽  
Masayasu Kitahashi ◽  
Toshiyuki Oshitari ◽  
...  
Keyword(s):  
Macular Hole ◽  
Visual Function ◽  
Spectral Domain ◽  
Optical Coherence ◽  
Macular Hole Surgery ◽  
Tomographic Images

Evaluation of Lamellar Macular Hole With Optical Coherence Tomography Angiography and Comparison Between Degenerative and Tractional Subtypes

2021 ◽  
Author(s):  
Burcu Polat Gültekin
Keyword(s):  
Optical Coherence Tomography ◽  
Macular Hole ◽  
Optical Coherence Tomography Angiography ◽  
Foveal Avascular Zone ◽  
Control Group ◽  
Vascular Density ◽  
Lamellar Macular Hole ◽  
Optical Coherence ◽  
Macular Holes ◽  
Significant Difference

Abstract Aim To evaluate the optical coherence tomography angiography (OCTA) findings in cases with degenerative and tractional-subtype lamellar macular hole (LMH). Methods Two sub-types of LMH cases were included. Thirty-seven patients had degenerative-subtype, whereas 35 patients had tractional-subtype LMH. Thirty healthy cases were enrolled as control group. Foveal avascular zone (FAZ), retinal vascular densities in superficial, deep capillary and choriocapillaris plexuses were analyzed and compared with fellow eyes and healthy controls using OCTA. Results Mean FAZ area was wider in the degenerative-subtype (0.33±0.14 mm²) than the tractional-subtype (0.24±0.10 mm²) (p=0.04) and control eyes (0.26±0.10 mm2) (p=0.02). Compared with the tractional group, foveal vessel density in the superficial layer was lower in the degenerative group (29.1±6.9% vs.21.9±9.2%, p=0.01). Choriocapillaris vascular density in the parafoveal area was also lower in the degenerative-subtype lamellar macular holes ( 61.8±4.7% vs. 63.2±4.2 %) (p=0.03). The vascular densities in the DCP did not disclose any significant difference between two sub-types (p>0.05). Compared with control eyes, the vascular densities in the superficial, deep and choriocapillaris layers were significantly lower in the LMH subtypes (p<0.05). Conclusion These OCTA changes may indicate a primary or secondary chronic degenerative process affecting the retinal microvascular plexuses in degenerative and tractional lamellar macular holes. The distinction of the pathogenesis is also demonstrated by OCTA and supports the recent change in classification and terminology of this macular pathology.

A Novel Prediction of Quaternary Structural Type of Proteins with Gene Ontology

2020 ◽  
Vol 27 (4) ◽  
pp. 313-320 ◽  
Author(s):  
Xuan Xiao ◽  
Wei-Jie Chen ◽  
Wang-Ren Qiu
Keyword(s):  
Gene Ontology ◽  
Feature Extraction ◽  
Extraction Method ◽  
Quaternary Structure ◽  
Structural Type ◽  
Sequence Information ◽  
Prediction System ◽  
Data Set ◽  
Feature Extraction Method ◽  
Prediction Rate

Background: The information of quaternary structure attributes of proteins is very important because it is closely related to the biological functions of proteins. With the rapid development of new generation sequencing technology, we are facing a challenge: how to automatically identify the four-level attributes of new polypeptide chains according to their sequence information (i.e., whether they are formed as just as a monomer, or as a hetero-oligomer, or a homo-oligomer). Objective: In this article, our goal is to find a new way to represent protein sequences, thereby improving the prediction rate of protein quaternary structure. Methods: In this article, we developed a prediction system for protein quaternary structural type in which a protein sequence was expressed by combining the Pfam functional-domain and gene ontology. turn protein features into digital sequences, and complete the prediction of quaternary structure through specific machine learning algorithms and verification algorithm. Results: Our data set contains 5495 protein samples. Through the method provided in this paper, we classify proteins into monomer, or as a hetero-oligomer, or a homo-oligomer, and the prediction rate is 74.38%, which is 3.24% higher than that of previous studies. Through this new feature extraction method, we can further classify the four-level structure of proteins, and the results are also correspondingly improved. Conclusion: After the applying the new prediction system, compared with the previous results, we have successfully improved the prediction rate. We have reason to believe that the feature extraction method in this paper has better practicability and can be used as a reference for other protein classification problems.

scholarly journals Refractory Myopic Retinal Detachment and Macular Hole Closure with Autologous Neurosensory Retinal Free Flap

2019 ◽  
Vol 10 (2) ◽  
pp. 160-164 ◽  
Author(s):  
Filipe Sousa Neves ◽  
Joana Braga ◽  
Paula Sepúlveda ◽  
Miguel Bilhoto
Keyword(s):  
Retinal Detachment ◽  
Macular Hole ◽  
Free Flap ◽  
Vision Loss ◽  
Silicone Oil ◽  
Modified Technique ◽  
Alternative Approach ◽  
Retinal Atrophy ◽  
One Year ◽  
Hole Closure

The purpose of this case report is to describe a modified technique involving the use of an autologous neurosensory retinal free flap for closure of a macular hole (MH) during retinal detachment (RD) surgery. A 50-year-old female presented with sudden vision loss (light perception only) and a recurrent myopic RD associated with an MH. An autologous neurosensory retinal free flap was obtained and moved toward the MH. Silicone oil was used as an endotamponade and removed after 6 months. Two months after oil removal visual acuity improved to 20/400 and remained stable thereafter; however, the patient developed central retinal atrophy. One year after surgery the MH was closed and the retina attached. This modified technique with the use of an autologous neurosensory retinal flap provides an alternative approach for recurrent MH in RD procedures.

scholarly journals Acceleration Feature Extraction of Human Body Based on Wearable Devices

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 924
Author(s):  
Zhenzhen Huang ◽  
Qiang Niu ◽  
Ilsun You ◽  
Giovanni Pau
Keyword(s):  
Genetic Algorithm ◽  
Feature Extraction ◽  
Kalman Filter ◽  
Human Body ◽  
Wearable Devices ◽  
Human Motion ◽  
Data Set ◽  
Feature Extraction Method ◽  
Motion Data ◽  
Kalman Filter Algorithm

Wearable devices used for human body monitoring has broad applications in smart home, sports, security and other fields. Wearable devices provide an extremely convenient way to collect a large amount of human motion data. In this paper, the human body acceleration feature extraction method based on wearable devices is studied. Firstly, Butterworth filter is used to filter the data. Then, in order to ensure the extracted feature value more accurately, it is necessary to remove the abnormal data in the source. This paper combines Kalman filter algorithm with a genetic algorithm and use the genetic algorithm to code the parameters of the Kalman filter algorithm. We use Standard Deviation (SD), Interval of Peaks (IoP) and Difference between Adjacent Peaks and Troughs (DAPT) to analyze seven kinds of acceleration. At last, SisFall data set, which is a globally available data set for study and experiments, is used for experiments to verify the effectiveness of our method. Based on simulation results, we can conclude that our method can distinguish different activity clearly.

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