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Three-Dimensional Segmentation and Quantitative Measurement of the Aqueous Outflow System of Intact Mouse Eyes Based on Spectral Two-Photon Microscopy Techniques
摘要： PURPOSE. To visualize and quantify the three-dimensional (3D) spatial relationships of the structures of the aqueous outflow system (AOS) within intact enucleated mouse eyes using spectral two-photon microscopy (TPM) techniques. METHODS. Spectral TPM, including two-photon autofluorescence (TPAF) and second-harmonic generation (SHG), were used to image the small structures of the AOS within the limbal region of freshly enucleated mouse eyes. Long infrared excitation wavelengths (930 nm) were used to reduce optical scattering and autofluorescent background. Image stacks were collected for 3D image rendering and structural segmentation. For anatomical reference, vascular perfusion with fluorescent-conjugated dextran (150 KDa) and trans-corneal perfusion with 0.1 lm fluorescent polystyrene beads were separately performed to identify the episcleral veins (EV) and the trabecular meshwork (TM) and Schlemm's canal (SC), respectively. RESULTS. Three-dimensional rendering and segmentation of spectral two-photon images revealed detailed structures of the AOS, including SC, collector channels (CC), and aqueous veins (AV). The collagen of the TM was detected proximal to SC. The long and short axes of the SC were 82.2 ± 22.2 μm and 6.7 ± 1.4 μm. The diameters of the CC averaged 25.6 ± 7.9 μm where they originated from the SC (ostia), enlarged to 34.1 ± 13.1 μm at the midpoint, and narrowed to 18.3 ± 4.8 μm at the junction of the AV. The diameter of the AV averaged 12.5 ± 3.4 μm. CONCLUSIONS. Spectral TPM can be used to reconstruct and measure the spatial relationships of both large and small AOS structures, which will allow for better understanding of distal aqueous outflow dynamics.
关键词： second-harmonic generation,aqueous outflow,nonlinear microscopy,glaucoma,two-photon fluorescence microscopy
更新于2025-11-21 11:08:12
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Improving Visual Field Examination of the Macula Using Structural Information
摘要： Purpose: To investigate a novel approach for structure-function modeling in glaucoma to improve visual field testing in the macula. Methods: We acquired data from the macular region in 20 healthy eyes and 31 with central glaucomatous damage. Optical coherence tomography (OCT) scans were used to estimate the local macular ganglion cell density. Perimetry was performed with a fundus-tracking device using a 10-2 grid. OCT scans were matched to the retinal image from the fundus perimeter to accurately map the tested locations onto the structural damage. Binary responses from the subjects to all presented stimuli were used to calculate the structure-function model used to generate prior distributions for a ZEST (Zippy Estimation by Sequential Testing) Bayesian strategy. We used simulations based on structural and functional data acquired from an independent dataset of 20 glaucoma patients to compare the performance of this new strategy, structural macular ZEST (MacS-ZEST), with a standard ZEST. Results: Compared to the standard ZEST, MacS-ZEST reduced the number of presentations by 13% in reliable simulated subjects and 14% with higher rates (≥20%) of false positive or false negative errors. Reduction in mean absolute error was not present for reliable subjects but was gradually more important with unreliable responses (≥10% at 30% error rate). Conclusions: Binary responses can be modeled to incorporate detailed structural information from macular OCT into visual field testing, improving overall speed and accuracy in poor responders. Translational Relevance: Structural information can improve speed and reliability for macular testing in glaucoma practice.
关键词： glaucoma,ganglion cells,optical coherence tomography,perimetry,visual field
更新于2025-09-23 15:23:52
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Eficacia y seguridad de la ciclofotocoagulación transescleral con micropulsos en el tratamiento del glaucoma
摘要： Objective: To report the results using Micropulse? transscleral cyclophotocoagulation (Iridex) in the treatment of glaucoma. Methods: Retrospective study in adult patients with glaucoma with at least 6 months of follow-up, and only one session of Micropulse?. The same surgical technique was used in all cases. The only laser parameter that could vary was the total treatment duration (in seconds). The remaining parameters were fixed at 2 Watts of power and 0.5 ms (31.3%) of active cycle. Results: A total of 22 eyes of 17 patients with glaucoma of various types and stages were included (mainly congenital and pseudoexfoliation). The mean follow-up time was 7.9 months. The total treatment duration varied from 100 to 180 seconds. Definition of success: 5 mmHg < Intraocular pressure (IOP) < 21 mm Hg and a reduction of ≥ 20% of the baseline value and no addition of oral carbonic anhydrase inhibitors, and no re-operation. The overall success rate was 72.7% in the first month, 54% at 4 months, 41% at 6 months, and 27.3% at final follow-up. Patients with longer treatment durations (180s) achieved better results. The mean reduction in IOP in successful eyes was 36% (from 26.3 to 16.7 mm Hg, SD 4.58, P = .028). No complications were reported. Conclusions: In a heterogeneous population of glaucoma (mostly congenital and pseudoexfoliation types), a low success rate (27.3%) was obtained in the medium-term with a single session of Micropulse?.
关键词： Infrared diode laser,Glaucoma,Micropulse?,Cyclophotocoagulation
更新于2025-09-23 15:23:52
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Comparison between broadband and monochromatic photopic negative response in full-field electroretinogram in controls and subjects with primary open-angle glaucoma
摘要： Purpose A prospective, cross-sectional, case–control study was conducted to investigate the role of broadband and monochromatic photopic negative response (PhNR) of the full-field flash electroretinogram (ERG) in the evaluation of ganglion cell damage in primary open-angle glaucoma (POAG) subjects. Methods Subjects with POAG and age-matched normal subjects were recruited from the outpatient department of a tertiary eye care center in South India. A total of 25 patients with POAG and 50 age-matched normal subjects were recruited. ERG was recorded using broadband (3.5 cd.s/m2 white stimulus on 10 cd/m2 white background) and monochromatic (3.5 cd.s/m2 red stimulus on 10 cd/m2 blue background and 1 cd.s/m2 blue stimulus on 10 cd/m2 yellow background) stimuli. Results The reduction in PhNR amplitude in POAG compared to normal individuals was higher in red-on-blue PhNR [26.37 μV; p < 0.001, confidence interval (CI) 19.34 to 33.4] as compared to broadband stimuli (16.41 μV; p < 0.001, CI 8.68 to 24.13), and blue on yellow (21.96 μV; p < 0.001, CI 10.12 to 33.8). Red-on-blue PhNR amplitudes correlated better with mean deviation (MD; r = -0.66, p < 0.05), pattern standard deviation (PSD; r = -0.4, p = 0.04), visual field index (VFI; r = -0.58, p < 0.05), and retinal nerve fiber layer thickness (r = -0.67, p < 0.05) in comparison with broadband and monochromatic blue-on-yellow PhNR. Receiver operating characteristic curve revealed largest area under the curve (0.89) in red-on-blue PhNR compared to broadband (0.76) and blue on yellow (0.74). The sensitivity and specificity was also higher in red-on-blue PhNR (72% and 80%, respectively) as compared to the other stimuli (sensitivity and specificity of broadband 0.68 and 0.7, blue on yellow 0.64 and 0.7, respectively). Conclusion Correlation of PhNR with Humphrey visual field parameters and retinal nerve fiber layer thickness showed that red-on-blue PhNR can be a useful additional tool for clinical assessment of retinal ganglion cell dysfunction in glaucoma patients. Red-on-blue PhNR was more sensitive as compared to white-on-white and blue-on-yellow PhNR in identifying ganglion cell dysfunction and correlates well with other structural and functional tests for glaucoma such as MD, PSD, VFI, and RNFL thickness.
关键词： Primary open-angle glaucoma,Photopic negative response,Broadband ERG,Full-field electroretinogram,Monochromatic ERG
更新于2025-09-23 15:23:52
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Detection of visual field defects by opticians - with Damato Multifixation Campimetry Online
摘要： Purpose: To study Damato Multifixation Campimetry Online (DMCO), an inexpensive online visual field test, used for screening at optician shops in Denmark. Methods: This was an evaluation of a diagnostic test and customers were included if minimum 50 years old, with a visual acuity of minimum 0.5 and with less myopia than 6 D. Standard equipment was a computer, a wireless mouse and a computer monitor. We used the 'DMCO STANDARD 4,5' algorithm for screening. DMCO results were electronically transmitted to the authors. Customers with a positive DMCO test received an eye examination including the reference standard Humphrey Visual Field Analyzer 30–2 SITA Fast test. A subset of control participants with a negative DMCO test received the same examination in order to estimate the number of false and true negatives. DMCO specificity and sensitivity were estimated according to five reference standards with 95% confidence intervals. Results: The population comprised 627 individuals, 381 women and 246 men, from 13 optician shops. Mean age was 62 years (SD 7.4). DMCO was positive in 32 individuals and 27 individuals were classified as 'true positives' with diagnoses such as glaucoma, cataract and neurological visual field defects. Of the 595 individuals with a negative DMCO test, 110 were examined and nine individuals were classified as 'false negatives' according to diagnoses. Depending on reference the specificity was 97–99% and sensitivity was 14–69%. Conclusion: Screening with DMCO demonstrated high specificity, whereas sensitivity was unsatisfactory. Future studies with enough power to estimate the true sensitivity is needed.
关键词： Humphrey Field Analyzer,glaucoma,screening test,Damato Multifixation Campimetry Online,specificity,opticians/optometrists
更新于2025-09-23 15:23:52
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Development of a new algorithm based on FDT Matrix perimetry and SD-OCT to improve early glaucoma detection in primary care
摘要： Purpose: The purpose of this study was to develop an objective algorithm to discriminate the earliest stages of glaucoma using frequency doubling technology (FDT) Matrix perimetry and spectral domain-optical coherence tomography (OCT) technology to improve primary care detection. Materials and methods: Three hundred six eyes (mean age 58.67±15.12) from 161 patients were included and classified in the following three groups: 101 nonglaucoma (GI-NG), 100 glaucoma suspect (GII-SG), and 105 open-angle glaucoma (GIII-OAG). All participants underwent a visual field exploration using the Humphrey Matrix visual field instrument and retinal nerve fiber layer evaluation using the Topcon 3D OCT-2000. Pattern deviation plot was divided into 19 areas and five aggrupation or quadrants and ranked with a value between 0 and 4 according to its likelihood of normality, and differences among three groups were analyzed. Principal component analysis (PCA) was also used to extract the most notable features of FDT and OCT, and a logistic regression analysis was applied to obtain the classification rules. Results: Only area numbers 7 and 12 and the central zone of FDT Matrix showed statistical differences (P<0.05) between GI-NG and GII-SG. The classification rules were estimated by the four PCA obtained from FDT Matrix and 3D OCT-2000 in a separate and combined use. Area under the receiver operating characteristic curve was 78.88% with FDT-PCA, 82.09% with OCT-PCA, and 94.27% with combined use of FDT and OCT-PCA to discriminate GI-NG and GII-SG. Conclusion: The predictive rules based on FDT-PCA or OCT-PCA provide a high sensitivity and specificity to detect the earliest stages of glaucoma and even better in combined use. These predictive rules may help the future development of software for FDT Matrix perimetry and 3D OCT-2000, which will greatly improve their diagnostic ability, making them useful in daily practice in a primary care setting.
关键词： 3D OCT-2000,PCA,glaucoma,primary care,FDT Matrix
更新于2025-09-23 15:23:52
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Micropulse Versus Continuous Wave Transscleral Cyclophotocoagulation in Refractory Pediatric Glaucoma
摘要： The aim of this study was to compare the safety and efficacy of micropulse cyclophotocoagulation (MP-CPC) and transscleral continuous wave cyclophotocoagulation (CW-CPC) for the treatment of refractory glaucoma in the pediatric age group. This prospective study included 45 eyes of 36 children requiring transscleral cyclophotocoagulation, in the period spanning from September 2016 to August 2017, using micropulse (MP-CPC) or continuous wave (CW-CPC) modes. The intraocular pressure (IOP) reduction, success rates, and complications were compared for both groups. Success was defined as an IOP of 5 to 21 mm Hg, in the absence of vision-threatening complications at 6 months. The MP-CPC group included 17 eyes, in patients aged 67.8 ± 48 months, and the CW-CPC group included 28 eyes, in patients aged 61.3 ± 38.3 months. There was a tendency toward lower IOP in the MP-CPC group at all follow-ups, almost reaching statistical significance at 2 weeks and 3 months (P = 0.05). IOP reduction was 63% in the MP-CPC group and 67% in the CW-CPC group (P = 0.6). The success rate was higher in the MP-CPC group (71% vs. 46% in the CW-CPC group), but the difference was not significant (P = 0.1). No significant complications were noted in the MP-CPC group whereas, in the CW-CPC group, 1 eye developed phthisis bulbi, and 2 eyes had severe pain and uveitis (P = 0.3). Both the MP-CPC and CW-CPC are effective in lowering the IOP in children with refractory glaucoma. However, the rate of complications, pain, and inflammation seem to be lower with the micropulse mode, making it a safer alternative for cyclophotocoagulation, especially since retreatments are often needed.
关键词： micropulse laser,cyclophotocoagulation,pediatric glaucoma
更新于2025-09-23 15:23:52
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Optical Coherence Tomography Angiography of Optic Disc and Macula Vessel Density in Glaucoma and Healthy Eyes
摘要： Aim: To study the microvascular density of the macular and optic nerve head in healthy and glaucoma subjects using optical coherence tomography angiography. Methodology: We performed a cross-sectional cohort study on healthy subjects and patients with glaucoma. The AngioVue Enhanced Microvascular Imaging System was used to capture the optic nerve head and macula images during one visit. En face segment images of the macular and optic disc were studied in layers. Microvascular density of the optic nerve head and macula were quanti?ed by the number of pixels measured by a novel in-house developed software. Areas under the receiver operating characteristic curves (AUROC) were used to determine the accuracy of differentiating between glaucoma and healthy subjects. Results: A total of 24 (32 eyes) glaucoma subjects (57.5 ± 9.5-y old) and 29 (58 eyes) age-matched controls (51.17 ± 13.5-y old) were recruited. Optic disc and macula scans were performed showing a greater mean vessel density (VD) in healthy compared with glaucoma subjects. The control group had higher VD than the glaucoma group at the en face segmented layers of the optic disc (optic nerve head: 0.209 ± 0.05 vs. 0.110 ± 0.048, P < 0.001; vitreoretinal interface: 0.086 ± 0.045 vs. 0.052 ± 0.034, P = 0.001; radial peripapillary capillary: 0.146 ± 0.040 vs. 0.053 ± 0.036, P < 0.001; and choroid: 0.228 ± 0.074 vs. 0.165 ± 0.062, P < 0.001). Similarly, the VD at the macula was also greater in controls than glaucoma patients (super?cial retina capillary plexus: 0.115 ± 0.016 vs. 0.088 ± 0.027, P < 0.001; deep retina capillary plexus: 0.233 ± 0.027 vs. 0.136 ± 0.073, P < 0.001; outer retinal capillary plexus: 0.190 ± 0.057 vs. 0.136 ± 0.105, P = 0.036; and choriocapillaris: 0.225 ± 0.053 vs. 0.153 ± 0.068, P < 0.001. The AUROC was highest for optic disc radial peripapillary capillary (0.96), followed by nerve head (0.92) and optic disc choroid (0.76). At the macula, the AUROC was highest for deep retina (0.86), followed by choroid (0.84), super?cial retina (0.81), and outer retina (0.72). Conclusions: Microvascular density of the optic disc and macula in glaucoma patients was reduced compared with healthy controls. VD of both optic disc and macula had a high diagnostic ability in differentiating healthy and glaucoma eyes.
关键词： optical coherence tomography angiography,glaucoma,microvascular density
更新于2025-09-23 15:23:52
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Automatic determination of vertical cup-to-disc ratio in retinal fundus images for glaucoma screening
摘要： Glaucoma is a chronic progressive optic neuropathy that causes visual impairment or blindness, if left untreated. It is crucial to diagnose it at an early stage in order to enable treatment. Fundus photography is a viable option for population-based screening. A fundus photograph enables the observation of the excavation of the optic disc - the hallmark of glaucoma. The excavation is quanti?ed as vertical cup-to-disc ratio (VCDR). The manual assessment of retinal fundus images is, however, time-consuming and costly. Thus, an automated system is necessary to assist human observers. We propose a computer aided diagnosis system, which consists of localization of the optic disc, determination of the height of the optic disc and the cup, and computation of the VCDR. We evaluated the performance of our approach on eight publicly available data sets, which have in total 1712 retinal fundus images. We compared the obtained VCDR values with those provided by an experienced ophthalmologist and achieved a weighted VCDR mean difference of 0.11. The system provides a reliable estimation of the height of the optic disc and the cup in terms of the Relative Height Error (RHE = 0.08 and 0.09, respectively). Bland-Altman analysis showed that the system achieves a good agreement with the manual annotations especially for large VCDRs, which indicate pathology.
关键词： GMLVQ,Glaucoma,retinal fundus images,vertical cup-to-disc ratio,trainable COSFIRE ?lters
更新于2025-09-23 15:23:52
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[IEEE 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - Mon Tresor, Plaine Magnien, Mauritius (2018.12.6-2018.12.7)] 2018 International Conference on Intelligent and Innovative Computing Applications (ICONIC) - Optic Disc Segmentation Based on Correlation Feature Information
摘要： Glaucoma, one of the major causes of blindness, has been identified as a disease that causes the degeneration of the optic disc. An highly accurate automated detection of the optic disc (OD) has however been noted to be of great importance for the efficient diagnosis of the disease. This paper presents a study on an unsupervised approach usage of Haralick Correlation texture feature for the segmentation of optic disc in colored fundus retinal images. The grayscale and green channel of the colored fundus image are investigated. When compared with some methods in the literature, the experimental study of the proposed method achieved very high average accuracy rates of 98.59% and 98.36% using grayscale and green channel of the colored fundus image respectively on DRIVE database.
关键词： Optic disc,Segmentation,Correlation,Haralick Feature,image processing,Glaucoma
更新于2025-09-23 15:22:29