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Comparison of Central Corneal Thickness using Anterior Segment Optical Coherence Tomography Versus Ultrasound Pachymetry
摘要： Introduction: Corneal thickness is an important and sensitive indicator of corneal health. It is useful in monitoring corneal diseases such as corneal oedema and keratoconus, and selecting patients for refractive surgery. Central Corneal Thickness (CCT) is a risk factor for Primary Open-Angle Glaucoma (POAG). Aim: To compare CCT using ultrasound pachymetry and Anterior Segment Optical Coherence Tomography (AS-OCT), and also to find out the reproducibility of AS–OCT readings for both central and pericentral corneal areas. Materials and Methods: This prospective cross-sectional study was conducted on 120 patients above 40 years of age, and with clinically normal corneas, who underwent CCT measurements by both ultrasound and AS-OCT. Both the eyes were analysed. Two measurements by AS-OCT and 25 measurements by ultrasound pachymetry were taken. The readings were averaged and compared by paired t-test. Repeatability of the OCT pachymetry map sector averages, was assessed by pooled standard deviation, obtained from the two measurements taken from each eye. Results: The CCT in right eye by OCT and ultrasound was 516.28±29.76 μm and 532.42±29.71 μm, respectively. The CCT in left eye by OCT and ultrasound was 515.82±29.88 μm and 532.36±29.83 μm, respectively. The difference in CCT measurement by AS-OCT and ultrasound was statistically significant (p<0.001); mean ultrasound CCT being 16.14 μm and 16.54 μm greater than the mean AS-OCT, CCT in right eye and left eye respectively. For AS-OCT, intra-session repeatability was measured. Repeatability of the OCT mapping was 0.01 μm to 1.6 μm and 0.01 μm to 1.9 μm in the right eye and left eye respectively. Conclusion: The CCT measurement by ultrasound pachymetry gives higher values compared to AS-OCT measurement. Hence, they cannot be interchangeably used in clinical practice. The AS- OCT provides highly repeatable pachymetry map measurements both centrally and pericentrally.
关键词： Primary open-angle glaucoma,Reproducibility,2-mm pachymetry map
更新于2025-09-09 09:28:46
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Automated, Noncontact Intraocular Pressure Home Monitoring after Implantation of a Novel Telemetric Intraocular Pressure Sensor in Patients with Glaucoma: A Feasibility Study
摘要： Purpose. Reliable and regular assessment of intraocular pressure (IOP) is important for the monitoring of patients with glaucoma. The purpose of this study was to evaluate the feasibility of a novel system for the automated, noncontact measurement of IOP. Patients and Methods. A first-generation telemetric IOP sensor was previously implanted in the ciliary sulcus of six patients with open-angle glaucoma during cataract surgery. Using this technology, automated noninvasive tonometry may be performed in a home setting. In the present study, a modified sleep mask and a modified eyepatch with incorporated coil antennae for measurements during nighttime and daytime, respectively, were tested on a single patient. Results. In this feasibility study, the 24 h wear of the prototype measuring apparatus was well tolerated. Three sequences of 24 h IOP measurements with at least 200 IOP measurements per day were performed (Sequence 1: mean 19.6 ± 2.7 mmHg, range 13.4–28.7 mmHg; Sequence 2: mean 21.0 ± 3.0 mmHg, range 13.1–30.5 mmHg; Sequence 3: mean 19.9 ± 2.4 mmHg, range 12.6–27 mmHg). Conclusions. For the first time, repeated and automated 24-hour measurements are possible using a prototype noncontact reading system after implantation of a novel telemetric IOP sensor in patients with glaucoma.
关键词： noncontact tonometry,glaucoma,intraocular pressure,automated measurement,telemetric sensor
更新于2025-09-09 09:28:46
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Diagnostic Ability of Macular Ganglion Cell Layer Measurements in Glaucoma Using Swept Source Optical Coherence Tomography
摘要： Purpose: To evaluate diagnostic ability of macular ganglion cell complex (mGCC), macular ganglion cell inner plexiform layer (mGCIPL) measurements in glaucoma using swept source deep range imaging optical coherence tomography (DRI OCT-1, Topcon Co., Tokyo, Japan). Methods: From August of 2014 to July of 2015, 109 eyes of 109 subjects were assessed for the average thickness and sectional thickness of both mGCC and mGCIPL to determine whether there exists any significant difference among advanced stage glaucoma group, early stage glaucoma group and normal group in Swept source OCT. Comparisons were also made between the above measurements and circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements in their diagnostic accuracy, sensitivity, and specificity. Results: The diagnostic ability of mGCC based-mean thickness value (area under the curve [AUC] = 0.78/ 0.99) in detecting early stage glaucoma group as well as advanced stage group was not significantly different from that of cpRNFL thickness measurement. However, there was a significant difference in thickness between mGCIPL (AUC = 0.70) and cpRNFL in early stage glaucoma groups (p = 0.018). The sensitivities and specificities of mGCC were 0.95/0.97, and those of mGCIPL were 0.92/0.97, respectively. Conclusions: The two swept source OCT based methods measuring retinal ganglion cell layer thickness appeared to have a good diagnostic accuracy, high sensitivity and specificity in detecting glaucomatous eyes. Nevertheless, of the two methods, mGCC thickness measurement was more efficient in detecting early glaucomatous changes.
关键词： Macular ganglion cell complex,Swept source optical coherence tomography,Glaucoma,Macular ganglion cell and inner plexiform layer
更新于2025-09-09 09:28:46
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Multi-parametric Optic Disc Segmentation Using Superpixel Based Feature Classification
摘要： Glaucoma along with diabetic retinopathy is a major cause of vision blindness and is projected to affect over 80 million people by 2020. Recently, expert systems have matched human performance in disease diagnosis and proven to be highly useful in assisting medical experts in the diagnosis and detection of diseases. Hence, automated optic disc detection through intelligent systems is vital for early diagnosis and detection of Glaucoma. This paper presents a multi-parametric optic disk detection and localization method for retinal fundus images using region-based statistical and textural features. Highly discriminative features are selected based on the mutual information criterion and a comparative analysis of four benchmark classifiers: Support Vector Machine, Random Forest (RF), AdaBoost and RusBoost is presented. The results of the proposed RF classifier based pipeline demonstrate its highly competitive performance (accuracies of 0.993, 0.988 and 0.993 on the DRIONS, MESSIDOR and ONHSD databases) with the state-of-the-art, thus making it a suitable candidate for patient management systems for early diagnosis of the Glaucoma.
关键词： Random forest,AdaBoostM1,RusBoost,Glaucoma,Support vector machine
更新于2025-09-09 09:28:46
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Optic disc topography in Malay patients with normal-tension glaucoma and primary open-angle glaucoma
摘要： Background: There are limited data concerning the optic disc topography in normal-tension glaucoma (NTG) and primary open-angle glaucoma (POAG) patients living in Southeast Asian countries. This study aims to compare optic disc parameters in patients with NTG and POAG in Malaysia and to discuss the results in comparison with studies of NTG and POAG in other Asian countries. Methods: This prospective cross-sectional study was performed in two hospitals with glaucoma service in Malaysia from 2010 to 2012. Seventy-seven patients of Malay ethnicity were enrolled in this study, including 32 NTG patients and 45 POAG patients. Using the Heidelberg Retinal Tomograph III, we measured optic disc area, cup area, rim area, cup volume, rim volume, cup-to-disc area ratio, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean retinal nerve fiber layer thickness, and retinal nerve fiber layer cross-sectional area. Results: The eyes for NTG patients had significantly larger optic disc areas (2.65 [standard deviation, 0.41] vs 2.40 [standard deviation, 0.36] mm2, respectively; P=0.006) and cup areas (1.54 [standard deviation, 0.43] vs 1.32 [standard deviation, 0.40] mm2, respectively; P=0.027) compared with the eyes of POAG patients. Comparison of the other parameters between the two groups revealed no significant difference (P0.050). The moderate and severe NTG patients showed significantly deeper cups and larger disc and cup areas when compared with the moderate and severe POAG patients (P0.050). Conclusion: The NTG patients in this study have notably larger optic disc and cup areas than the POAG patients. Our observations are consistent with those reported in studies of NTG and POAG patients in Korea. The deeper cups and larger disc and cup areas may serve as indicators of severity when comparing NTG with POAG. However, these findings require verification with IOP and visual field results.
关键词： optic disc topography,primary open-angle glaucoma,Heidelberg Retina Topography III,Malay ethnicity,normal-tension glaucoma
更新于2025-09-04 15:30:14
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Blue Multifocal Pupillographic Objective Perimetry in Glaucoma
摘要： This study investigated multifocal pupillographic objective perimetry (mfPOP) stimuli that target the intrinsic photosensitivity of melanopsin retinal ganglion cells. The diagnostic potential for glaucoma is compared between stimuli biased toward either cone input to these cells or their melanopsin response. Nineteen glaucoma patients and 24 normal subjects were tested using mfPOP stimulus protocols with either 33-ms yellow or 750-ms blue stimuli. Subjects’ color discrimination was assessed using the Farnsworth 100-hue test. Pupillary responses were measured, and mixed-effects regression was used to quantify results. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) analysis. The mean reduction in moderate to severe glaucoma pupil responses using blue mfPOP stimuli was larger but more variable than that of the shorter yellow stimuli (blue: (cid:2)1.32 dB [t(40) ? (cid:2)2.29; P ? 0.027]; yellow: (cid:2)0.93 dB [t(40) ? (cid:2)3.13; P ? 0.003]). Color discrimination decreased signi?cantly with age and glaucoma, with type III blue-yellow anomalies dominating. ROC analysis revealed similar diagnostic accuracies (AUC for eyes classi?ed as moderate to severe; blue: 81.7%, yellow: 83.7). Slightly higher sensitivity and speci?city were obtained using blue stimuli in mild disease (AUCs blue: 71.1, cf. yellow: 67.7), although this difference was not signi?cant. In moderate to severe glaucoma, diagnostic accuracy of yellow and blue was similar, but blue stimuli showed limited ability to resolve scotomas. Blue mfPOP stimuli, however, may have advantages over yellow in detecting early glaucoma.
关键词： pupil,melanopsin,visual ?eld,glaucoma
更新于2025-09-04 15:30:14
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The Usefulness of Gaze Tracking as an Index of Visual Field Reliability in Glaucoma Patients
摘要： PURPOSE. We evaluated the usefulness of gaze tracking (GT) results as an index of visual ?eld reliability in glaucoma. METHODS. The study population consisted of 631 eyes of 400 patients with open angle glaucoma in an institutional practice, with 10 visual ?elds (VFs). For the observational procedure, visual ?xation was assessed using the gaze ?xation chart at the bottom of the VF (Humphrey Field Analyzer, 30-2 SITA standard) printout. Average frequency of eye movement between 18 and 28 (move1–2), 38 and 58 (move3–5), and greater than or equal to 68 (move?6) were calculated. In addition, average tracking failure frequency (TFF) and average blinking frequency (BF) were calculated. The relationship between mean deviation (MD), ?xation losses (FLs), false-positives (FPs), false-negatives (FNs), move1–2, move3–5, move?6, TFF, BF, and pattern standard deviation (PSD) were evaluated using linear modeling. Main outcome measures included parameters related to over- or underestimation of MD values. RESULTS. Patients’ mean MD progression rate was (cid:2)0.23 dB/y. The best model to predict MD values included FL rate, FP rate, move3–5, move?6, TFF, BF, and PSD as dependent variables with coef?cients of 0.90, 9.2, (cid:2)0.57, (cid:2)0.52, (cid:2)2.2, (cid:2)1.1, and (cid:2)0.56, respectively (P < 0.001). CONCLUSIONS. High FL and FP rates tend to raise MD values. By contrast, high values of move3–5, move?6, TFF, BF, and PSD tend to lower MD values. Thus, GT parameters can be used as new indices of VF reliability through the prediction of over- or underestimation of VF results.
关键词： glaucoma,visual ?eld,gaze tracking
更新于2025-09-04 15:30:14
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Does the Location of Bruch's Membrane Opening Change Over Time? Longitudinal Analysis Using San Diego Automated Layer Segmentation Algorithm (SALSA)
摘要： PURPOSE. We determined if the Bruch’s membrane opening (BMO) location changes over time in healthy eyes and eyes with progressing glaucoma, and validated an automated segmentation algorithm for identifying the BMO in Cirrus high-definition coherence tomography (HD-OCT) images. METHODS. We followed 95 eyes (35 progressing glaucoma and 60 healthy) for an average of 3.7 6 1.1 years. A stable group of 50 eyes had repeated tests over a short period. In each B-scan of the stable group, the BMO points were delineated manually and automatically to assess the reproducibility of both segmentation methods. Moreover, the BMO location variation over time was assessed longitudinally on the aligned images in 3D space point by point in x, y, and z directions. RESULTS. Mean visual field mean deviation at baseline of the progressing glaucoma group was (cid:2)7.7 dB. Mixed-effects models revealed small nonsignificant changes in BMO location over time for all directions in healthy eyes (the smallest P value was 0.39) and in the progressing glaucoma eyes (the smallest P value was 0.30). In the stable group, the overall intervisit–intraclass correlation coefficient (ICC) and coefficient of variation (CV) were 98.4% and 2.1%, for the respectively, automated algorithm for the manual segmentation and 98.1% and 1.9%, respectively, CONCLUSIONS. Bruch’s membrane opening location was stable in normal and progressing glaucoma eyes with follow-up between 3 and 4 years indicating that it can be used as reference point in monitoring glaucoma progression. The BMO location estimation with Cirrus HD-OCT using manual and automated segmentation showed excellent reproducibility.
关键词： BMO location variation,glaucoma,automated segmentation,reference plane
更新于2025-09-04 15:30:14
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Spectral-Domain Optical Coherence Tomography Features in Open-Angle Glaucoma With Diabetes Mellitus and Inadequate Glycemic Control
摘要： PURPOSE. To evaluate spectral-domain optical coherence tomography (SD-OCT) features according to glycemic control status in open-angle glaucoma with diabetes mellitus. METHODS. Subjects underwent comprehensive ocular examination, visual ?eld testing, and SD-OCT imaging (Cirrus HD-OCT). The relationship between glycosylated hemoglobin (HbA1c) and OCT measurements was compared between diabetic nonglaucomatous eyes and diabetic glaucomatous eyes. Glaucoma-discriminating ability was assessed using the area under the receiver operating characteristic curves (AUCs) for OCT parameters and compared between groups relative to the glycemic control group. RESULTS. Analysis was performed on 69 nonglaucomatous and 87 glaucomatous eyes in the nondiabetic group, and on 72 nonglaucomatous and 56 glaucomatous eyes in the diabetic group. Average, inferonasal, inferior, and inferotemporal ganglion cell–inner plexiform layer (GCIPL) thicknesses were positively correlated with HbA1c in diabetic nonglaucomatous eyes (P ? 0.040, 0.037, 0.025, and 0.013, respectively). The AUC of the average cup-to-disc area ratio (CDR), vertical CDR, and cup volume in diabetic eyes with poor glycemic control was signi?cantly higher than those in nondiabetic eyes (P ? 0.011, 0.003, and 0.043, respectively). The AUC of cube volume, cube average thickness, and minimal GCIPL thickness in diabetic eyes with poor glycemic control was lower than those in nondiabetic eyes (P ? 0.006, 0.007, and 0.004, respectively). CONCLUSIONS. In this study, optic nerve head parameters had a superior ability to discriminate glaucoma in diabetic eyes with poor glycemic control. Conversely, the ability to discriminate glaucoma using macular parameters tended to be lower for diabetic eyes with inadequate glycemic control.
关键词： spectral-domain optical coherence tomography,diabetes mellitus,ganglion cell-inner plexiform layer,glaucoma
更新于2025-09-04 15:30:14
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Comprehensive Three-Dimensional Analysis of the Neuroretinal Rim in Glaucoma Using High-Density Spectral-Domain Optical Coherence Tomography Volume Scans
摘要： To describe spectral-domain optical coherence tomography (OCT) methods for quantifying neuroretinal rim tissue in glaucoma and to compare these methods to the traditional retinal nerve fiber layer thickness diagnostic parameter. Neuroretinal rim parameters derived from three-dimensional (3D) volume scans were compared with the two-dimensional (2D) Spectralis retinal nerve fiber layer (RNFL) thickness scans for diagnostic capability. This study analyzed one eye per patient of 104 glaucoma patients and 58 healthy subjects. The shortest distances between the cup surface and the OCT-based disc margin were automatically calculated to determine the thickness and area of the minimum distance band (MDB) neuroretinal rim parameter. Traditional 150-lm reference surface–based rim parameters (volume, area, and thickness) were also calculated. The diagnostic capabilities of these five parameters were compared with RNFL thickness using the area under the receiver operating characteristic (AUROC) curves. The MDB thickness had significantly higher diagnostic capability than the RNFL thickness in the nasal (0.913 vs. 0.818, P ? 0.004) and temporal (0.922 vs. 0.858, P ? 0.026) quadrants and the inferonasal (0.950 vs. 0.897, P ? 0.011) and superonasal (0.933 vs. 0.868, P ? 0.012) sectors. The MDB area and the three neuroretinal rim parameters based on the 150-lm reference surface had diagnostic capabilities similar to RNFL thickness. The 3D MDB thickness had a high diagnostic capability for glaucoma and may be of significant clinical utility. It had higher diagnostic capability than the RNFL thickness in the nasal and temporal quadrants and the inferonasal and superonasal sectors.
关键词： neuroretinal rim,spectral-domain optical coherence tomography,glaucoma,optic disc,optic nerve
更新于2025-09-04 15:30:14