- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Evaluation of Structure-Function Relationships in Longitudinal Changes of Glaucoma using the Spectralis OCT Follow-Up Mode
摘要： The detection of glaucoma progression is an essential part of glaucoma management. Subjectivity of standard automated perimetry (SAP) prevents the accurate evaluation of progression, thus the detection of structural changes by optical coherence tomography (OCT) is attracting attention. Despite its objectivity, there is controversy about the appropriateness of the use of OCT, because many previous studies have indicated OCT results may not reflect the deterioration of visual field. A reason for this dissociation may be the test-retest variability of OCT, a major cause of which is misplacement of the measurement location. Recent advantages of spectral-domain OCT (SD-OCT), especially Spectralis OCT with an eye-tracking system (follow-up mode) enable measurement at approximately the same location as previous examinations. In addition to utilizing Spectralis follow-up mode, we introduced structure-function relationship map and nonlinear relationship between SAP and OCT results in considering structure-function relationship in longitudinal changes. The introduction of these two ideas in our study population improved the correlation between the SAP and OCT (R = 0.589 at most). The results of this study support the practical use of OCT in glaucoma progression but also stress the importance of focus on the corresponding focal changes and the consideration of disease severity.
关键词： longitudinal study,standard automated perimetry,optical coherence tomography,structure-function relationship,glaucoma progression
更新于2025-09-10 09:29:36
-
Computer aided diagnosis of glaucoma using discrete and empirical wavelet transform from fundus images
摘要： Glaucoma is a class of eye disorder; it causes progressive deterioration of optic nerve fibres. Discrete wavelet transforms (DWTs) and empirical wavelet transforms (EWTs) are widely used methods in the literature for feature extraction using image decomposition. However, to increase the accuracy for measuring features of images a hybrid and concatenation approach has been presented in the proposed research work. DWT decomposes images into approximate and detail coefficients and EWT decomposes images into its sub band images. The concatenation approach employs the combination of all features obtained using DWT and EWT and their combination. Extracted features from each of DWT, EWT, DWTEWT and EWTDWT are concatenated. Concatenated features are normalised, ranked and fed to singular value decomposition to find robust features. Fourteen robust features are used by support vector machine classifier. The obtained accuracy, sensitivity and specificity are 83.57, 86.40 and 80.80%, respectively, for tenfold cross validation which outperforms the existing methods of glaucoma detection.
关键词： glaucoma,empirical wavelet transform,support vector machine,discrete wavelet transform,feature extraction
更新于2025-09-10 09:29:36
-
Review: Measurement Techniques for Intraocular Pressure
摘要： The literature on intra-ocular pressure dynamics is reviewed, including tonometer design and calibration, the influence of corneal-scleral mechanics, and scleral rigidity factors. Drugs that influence the outflow facility of the trabecular meshwork (TM) are discussed. Transmural pressure drop across the lamina cribosa (LC) is an important parameter, in terms of quantifying potential glaucoma damage to the optic nerve.
关键词： Glaucoma,Ocular rigidity,Calibration,Intraocular pressure,Tonometer
更新于2025-09-10 09:29:36
-
Parameters of ocular fundus on spectral-domain optical coherence tomography for glaucoma diagnosis
摘要： In this review, we summarize the progression of several parameters assessed by spectral-domain optical coherence tomography (SD-OCT) in recent years for the detection of glaucoma. Monitoring the progression of defects in the retinal nerve fiber layer (RNFL) thickness is essential. Imaging and analysis of retinal ganglion cells (RGCs) and inner plexiform layer (IPL), respectively, have been of great importance. Optic nerve head (ONH) topography obtained from 3D SD-OCT images is another crucial step. Other important assessments involve locating the Bruch’s membrane opening (BMO), estimating the optic disc size and rim area, and measuring the lamina cribrosa displacement. Still other parameters found in the past three years for glaucoma diagnosis comprise central retinal artery resistive index, optic disc perfusion in optical coherence tomography angiography (OCTA) study, peripapillary choroidal thickness, and choroidal area in SD-OCT. Recently, several more ocular fundus parameters have been found, and compared with the earlier parameters to judge the accuracy of diagnosis. While a few of these parameters have been widely used in clinical practice, a fair number are still in the experimental stage.
关键词： optic nerve head,retinal nerve fiber layer,lamina cribrosa,optical coherence tomography,macular thickness,ganglion cells,glaucoma progression
更新于2025-09-09 09:28:46
-
Prevalence and type of artefact with spectral domain optical coherence tomography macular ganglion cell imaging in glaucoma surveillance
摘要： Purpose The ganglion cell analysis (GCA) of the CIRRUSTM HD-OCT (Carl Zeiss, Meditec; Dublin, CA) provides measurement of the macular ganglion cell-inner plexiform layer (GCIPL) thickness. This study determined the frequency of scan artefacts and errors in GCIPL imaging in individuals undergoing HD-OCT surveillance for glaucoma. Method A total of 1439 eyes from 721 subjects enrolled in a prospective study assessing predictors of glaucoma progression underwent macular GCIPL imaging with the CIRRUS HD-OCT at recruitment. The prevalence of acquisition errors, segmentation errors, and co-morbid macular pathology was determined. Results A total of 87 (6.0%) of the 1439 scans had either acquisition errors, segmentation artefacts, or other macular pathology. The most common co-morbid macular pathology was epiretinal membrane in 2.2% of eyes. Conclusion The macular GCIPL scan was artefact free in 94% of eyes. However, epiretinal membrane and high myopia can cause scan artefact and should be considered when interpreting the results.
关键词： glaucoma,optical coherence tomography,ganglion cell analysis,scan artefacts,macular pathology
更新于2025-09-09 09:28:46
-
[IEEE 2018 IEEE International Systems Engineering Symposium (ISSE) - Rome, Italy (2018.10.1-2018.10.3)] 2018 IEEE International Systems Engineering Symposium (ISSE) - Implementation of support tools for the presumptive diagnosis of Glaucoma through identification and processing of medical images of the human eye
摘要： In medicine, the diagnosis of diseases by means of image processing has had great acceptability and credibility, which is why it has been able to explore in depth the theme, taking advantage of mainly which is a non-invasive method within the clinical study. Glaucoma is considered as a group of diseases that damages the optic nerve to the point of causing blindness in the eye, with the disadvantage of in most cases do not exhibit early symptoms. Through this work, the processing biomedical images to locate the parameters considered most relevant within images obtained from the back of the eye to make the determination of the existence or not of Glaucoma, a disease that mainly affects physically the dimensions and proportions of the cup and the optical disc. It gets the value of the reason cup/disc and is additional to the characteristics of the rule ISNT, both parameters considered of great importance in the diagnosis of glaucoma. The results obtained serve as a tool to support the specialist in ophthalmology and optometry in conjunction with a presumptive diagnosis of glaucoma, this way it looks for the early detection and prevention of this disease.
关键词： ISNT,visual field,cup-disc,Glaucoma,nerve fibers,image processing,optic nerve
更新于2025-09-09 09:28:46
-
[IEEE 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI) - Tirunelveli, India (2018.5.11-2018.5.12)] 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI) - Analysis of CDR of Fundus Images for Glaucoma Detection
摘要： Glaucoma is the second leading cause of blindness in the world. It is estimated that 66.8 million people in the world have glaucoma, with 6.7 million bilaterally blind from this disease. There are no early symptoms of glaucoma and the only source to detect glaucoma at early stage is the structural change that arises in the internal eye. Many autonomous glaucoma detection systems analyze fundus image by calculating its Cup to Disc Ratio (CDR) and categorize the image as glaucoma or healthy. This paper is on image processing technique for the early detection of glaucoma. In this paper glaucoma is detected using retinal fundus image. CDR technique is used on different retinal image for glaucoma detection. Further, analysis of CDR is carried out using different color channel combinations of the fundus images.
关键词： Optic Cup,Glaucoma,CDR,Fundus Image,Optic Disc
更新于2025-09-09 09:28:46
-
Clinical relevance of protruded retinal layers in minimum rim width measurement of the optic nerve head
摘要： background/aims Optical coherence tomography (OCT) imaging of the optic nerve head minimum rim width (MRW) has recently been shown to sometimes contain components besides extended retinal nerve fibre layer (RNFL). This study was conducted to determine whether excluding these components, termed protruded retinal layers (PRLs), from MRW increases diagnostic accuracy for detecting glaucoma. Methods In this cross-sectional study, we included 123 patients with glaucoma and 123 normal age-similar controls with OCT imaging of the optic nerve head (24 radial scans) and RNFL (circle scan). When present, PRLs were manually segmented, and adjusted MRW measurements were computed. We compared diagnostic accuracy of adjusted versus unadjusted MRW measurement. We also determined whether adjusted MRW correlates better with RNFL thickness compared with unadjusted MRW. results The median (IQR) visual field mean deviation of patients and controls was ?4.4 (?10.3 to ?2.1) dB and 0.0 (?0.6 to 0.8) dB, respectively. In the 5904 individual B-scans, PRLs were identified less frequently in patients (448, 7.6%) compared with controls (728, 12.3%; p<0.01) and were present most frequently in the temporal sector of both groups. Areas under the receiver operating characteristic curves and sensitivity values at 95% specificity indicated that PRL adjustment did not improve diagnostic accuracy of MRW, globally or temporally. Furthermore, adjusting MRW for PRL did not improve its correlation with RNFL thickness in either group. Conclusion While layers besides the RNFL are sometimes included in OCT measurements of MRW, subtracting these layers does not impact clinical utility.
关键词： minimum rim width,OCT imaging,glaucoma,protruded retinal layers,optic nerve head
更新于2025-09-09 09:28:46
-
Diurnal Intraocular Pressure and the Relationship With Swept-Source OCT–Derived Anterior Chamber Dimensions in Angle Closure: The IMPACT Study
摘要： PURPOSE. To evaluate diurnal intraocular pressure (DIOP) among individuals with primary angle closure (PAC) or primary angle-closure suspect (PACS). Additionally, the hypothesis that greater DIOP ?uctuation is related to smaller angle parameters was investigated. METHODS. Forty Caucasian newly referred untreated patients with bilateral PAC or PACS were recruited. Intraocular pressure (IOP) was measured hourly between 9 AM and 4 PM with Goldmann applanation tonometry. Diurnal IOP ?uctuation was de?ned as difference between maximum and minimum IOP. Angle opening distance (AOD), trabecular–iris angle (TIA), angle recess area (ARA), and trabecular–iris space area (TISA) were measured with anterior segment optical coherence tomography (AS-OCT) in dark (0.3–0.5 lux) and light (170–200 lux) on the same day as DIOP measurements in eight angle sections. RESULTS. Intraocular pressure declined as the day progressed (P < 0.001), unrelated to presence of peripheral anterior synechiae (PAS). At each time point, eyes with PAS (n ? 31) had signi?cantly higher IOPs than eyes without PAS (n ? 49; P ? 0.043). Diurnal IOP ?uctuation varied from 1.50 to 14.50 mm Hg (mean 5.99 mm Hg, SD 2.70 mm Hg). Diurnal IOP ?uctuation was unrelated to PAS. Multiple-predictor models investigating association of angle dimensions and greater DIOP ?uctuation were statistically signi?cant for AOD 750 (light), ARA 750 (light and dark), TISA 500 (light), TISA 750 (light), TIA 500 (light), and TIA 750 (light and dark). CONCLUSIONS. Diurnal IOP variation has clinical implications given that IOP level is used to distinguish between diagnostic categories of PACS and PAC. Optical coherence tomography angle parameter measurements may predict for magnitude of IOP diurnal ?uctuations in at-risk patients, which may be clinically useful when a clinical intervention is being considered.
关键词： glaucoma,intraocular pressure,angle closure
更新于2025-09-09 09:28:46
-
Retinal Nerve Fiber Layer Defect Volume Deviation Analysis Using Spectral-Domain Optical Coherence Tomography
摘要： PURPOSE. To report the retinal nerve ?ber layer (RNFL) defect volume deviation according to structural RNFL loss in RNFL thickness maps. METHODS. Retinal nerve ?ber layer defect is de?ned in RNFL thickness maps by the degree of RNFL loss. A 20% to 70% degree of RNFL loss was set with a 1% interval as the reference level for determining the boundary of RNFL defects. Each individual RNFL thickness map was compared with a normative database map and the region below the reference level was identi?ed as an RNFL defect. The RNFL defect volume was calculated by summing the volumes of each pixel inside RNFL defect. The RNFL defect volume deviation was calculated by summing the differences between the normative database and the subject’s RNFL measurements. To evaluate the glaucoma diagnostic ability, the areas under the receiver operating characteristics curves (AUCs) were calculated. RESULTS. Retinal nerve ?ber layer defect volume and RNFL defect volume deviation (0.984 and 0.986, respectively) had signi?cantly greater AUCs than all circumpapillary RNFL thickness parameters (all P < 0.001). In the early stage of RNFL loss (under 31% loss of RNFL), RNFL defect volume deviation showed better diagnostic performance than the RNFL defect volume. In multivariate analysis, RNFL defect volume and RNFL defect volume deviation were signi?cantly associated with the mean deviation in visual ?eld tests. CONCLUSIONS. Retinal nerve ?ber layer defect volume deviation is a useful tool for diagnosing glaucoma and monitoring RNFL change. In early stage of RNFL loss, RNFL defect volume deviation is more sensitive for detecting glaucoma than the RNFL defect volume measurements.
关键词： retinal nerve ?ber defect,spectral-domain optical coherence tomography,lost and remaining volume,glaucoma
更新于2025-09-09 09:28:46