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Next Generation PERG Method: Expanding the Response Dynamic Range and Capturing Response Adaptation
摘要： Purpose: To compare a new method for steady-state pattern electroretinogram (PERGx) with a validated method (PERGLA) in normal controls and in patients with optic neuropathy. Methods: PERGx and PERGLA were recorded in a mixed population (n ? 33, 66 eyes) of younger controls (C1; n ? 10, age 38 6 8.3 years), older controls (C2; n ? 11, 57.9 6 8.09 years), patients with early manifest glaucoma (G; n ? 7, 65.7 611.6 years), and patients with nonarteritic ischemic optic neuropathy (N; n ? 5, mean age 59.4 6 8.6 years). The PERGx stimulus was a black-white horizontal grating generated on a 14 3 14 cm LED display (1.6 cycles/deg, 15.63 reversals/s, 98% contrast, 800 cd/m2 mean luminance, 258 field). PERGx signal and noise were averaged over 1024 epochs (~2 minutes) and Fourier analyzed to retrieve amplitude and phase. Partial averages (16 successive samples of 64 epochs each) were also analyzed to quantify progressive changes over recording time (adaptation). Results: PERGLA and PERGx amplitudes and latencies were correlated (Amplitude R2 ? 0.59, Latency R2 ? 0.39, both P , 0.0001) and were similarly altered in disease. Compared to PERGLA, however, PERGx had shorter (16 ms) latency, higher (1.393) lower (0.373) noise, and higher (4.23) signal-to-noise ratio. PERGx amplitude, displayed marked amplitude adaptation in C1 and C2 groups and no significant adaptation in G and N groups. Conclusions: The PERGx high signal-to-noise ratio may allow meaningful recording in advanced stages of optic nerve disorders. it quantifies response adaptation, which may be selectively altered in glaucoma and optic neuropathy.
关键词： signal-to-noise ratio,non-arteritic ischemic optic neuropathy,neural adaptation,glaucoma,pattern electroretinogram
更新于2025-09-04 15:30:14
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Exploring Test–Retest Variability Using High-Resolution Perimetry
摘要： Purpose: Test–retest variability (TRV) of visual field (VF) data seriously degrades our capacity to recognize true VF progression. We conducted repeated high-resolution perimetry with a test interval of 0.58 to investigate the sources of TRV. In particular, we examined whether the spatial variance of the observed sensitivity changes or if their absolute magnitude was of more importance. Methods: Sixteen eyes of 16 glaucoma patients were each tested three times at 61 VF locations along the superior-temporal 458 meridian using a modified protocol of the Octopus 900 perimeter. TRV was quantified as the standard deviation of the repeats at each point (retest-SD). We also computed the mean sensitivity at each point (retest-MS) and the running spatial-SD along the tested meridian. Multiple regression models investigated whether any of those variables (and also age, sex, and VF eccentricity) were significant independent determinants of TRV. Results: The main independent determinants of TRV were the retest-MS at (cid:2)0.04 dB TRV/dB loss (P , 0.0001, t-statistic 5.05), and the retest-SD at 0.47 dB spatial variance/dB loss (P , 0.0001, t-statistic 12.5). Conclusions: The larger effect for the spatial-SD suggested that it was perhaps a stronger determinant of TRV than scotoma depth per se. This might support the hypothesis that rapidly varying interactions between small perimetric stimuli, sensitivity across the field, and normal fixational jitter are strong determinants of TRV. Translational Relevance: Our study indicates that methods that might reduce the effects of jagged sensitivity changes, such as increasing stimulus size or better gaze tracking, could reduce TRV.
关键词： glaucoma,high-resolution perimetry,test–retest variability
更新于2025-09-04 15:30:14
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Evaluation of a Region-of-Interest Approach for Detecting Progressive Glaucomatous Macular Damage on Optical Coherence Tomography
摘要： Purpose: To evaluate a manual region-of-interest (ROI) approach for detecting progressive macular ganglion cell complex (GCC) changes on optical coherence tomography (OCT) imaging. Methods: One hundred forty-six eyes with a clinical diagnosis of glaucoma or suspected glaucoma with macular OCT scans obtained at least 1 year apart were evaluated. Changes in the GCC thickness were identified using a manual ROI approach (ROIM), whereby region(s) of observed or suspected glaucomatous damage were manually identified when using key features from the macular OCT scan on the second visit. Progression was also evaluated using the global GCC thickness and an automatic ROI approach (ROIA), where contiguous region(s) that fell below the 1% lower normative limit and exceeded 288 lm2 in size were evaluated. Longitudinal signal-to-noise ratios (SNRs) were calculated for progressive changes detected by each of these methods using individualized estimates of test–retest variability and age-related changes, obtained from 303 glaucoma and 394 healthy eyes, respectively. Results: On average, the longitudinal SNR for the global thickness, ROIA and ROIM methods were (cid:2)0.90 y(cid:2)1, (cid:2)0.91 y(cid:2)1, and (cid:2)1.03 y(cid:2)1, respectively, and was significantly more negative for the ROIM compared with the global thickness (P ? 0.003) and ROIA methods (P ? 0.021). Conclusions: Progressive glaucomatous macular GCC changes were optimally detected with a manual ROI approach. Translational Relevance: These findings suggests that an approach based on a qualitative evaluation of OCT imaging information and consideration of known patterns of damage can improve the detection of progressive glaucomatous macular damage.
关键词： progression,optical coherence tomography,macula,glaucoma
更新于2025-09-04 15:30:14
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Glaucoma diagnosis using discrete wavelet transform and histogram features from fundus images
摘要： Glaucoma is one of the main eye diseases; it cause progressive deterioration of optic nerve fibers due to increased fluid pressure. The existing methods of glaucoma diagnosis are time consuming, expensive and require practiced clinicians to understand the eye problems. Hence fast, cheap and more accurate glaucoma diagnosis methods are needed. This paper presents an innovative idea for diagnosis of glaucoma using third level two dimensional discrete wavelet transform (2D DWT) and histogram features from fundus images. The 2D DWT is used to decompose the glaucoma and healthy images and histogram features are extracted from 2D DWT decomposed sub band images. The least square support vector machine (LS-SVM) is used as a classifier which classifies the glaucoma and healthy images using the extracted features. The proposed method yielded classification accuracy of 88.33%, 87.50%, and 86.67% for ten, eight and five-fold cross validation respectively. The obtained classification accuracy, sensitivity and specificity are 88.33%, 90.00%, and 85.00% for tenfold cross validation respectively. Obtained results prove that the performance of the proposed method is better compared to the existing methods. It may considerably increases the diagnosis speed of ophthalmologists.
关键词： Discrete Wavelet Transform,Feature Extraction,Glaucoma,Support Vector Machine,Pre-Processing
更新于2025-09-04 15:30:14
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Pseudoexfoliation material on posterior chamber intraocular lenses
摘要： The presence of pseudoexfoliation material on the surface of an intraocular lens (IOL) is a rare finding. We report a series of seven cases with different patterns of pseudoexfoliation material deposition on the posterior chamber IOLs, recognized 2–20 years after cataract surgery. Six patients had an IOL implanted in the capsular bag and one in the ciliary sulcus. Two patients had undergone posterior capsulotomy. Although the pathophysiological mechanisms and clinical significance of this finding remain unknown, the careful follow-up of pseudophakic patients with known or suspected pseudoexfoliation syndrome is essential to monitor the development or progression of glaucoma, since deposition of pseudoexfoliation material continues even after cataract surgery.
关键词： cataract,intraocular lens,exfoliation syndrome,glaucoma
更新于2025-09-04 15:30:14
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Correlation between optic nerve head structural parameters and glaucomatous visual field indices
摘要： We examined associations between optic nerve head structural parameters and glaucomatous visual field indices. The study population included patients with glaucomatous optic neuropathy who were evaluated at Aichi Medical University, Nagakute, Aichi, Japan, from October 2010 to January 2011. A total of 57 eyes from 33 patients were assessed. We measured visual field using a Humphrey field analyzer, peripapillary retinal nerve fiber layer thickness (RNFL-T), and Bruch’s membrane opening-minimum rim width (BMO-MRW) using spectral domain optical coherence tomography, and rim area with referring three-dimensional photography. Spearman’s rank correlation coefficients were calculated between the threshold of visual sensitivity or total deviation of visual field and the following five optic nerve head structural parameters: RNFL-T length, BMO-MRW length, rim area, and calculated RNFL-T and BMO-MRW volumes (each length multiplied by rim area). The Akaike information criterion was calculated to determine which structural parameter was the best predictor of each visual field index. Threshold of visual sensitivity had correlation coefficients of 0.23 with global sector of RNFL-T, 0.32 with BMO-MRW, 0.14 with rim area, 0.21 with RNFL-T volume, and 0.26 with BMO-MRW volume. The correlation coefficients for each parameter with total deviation of visual field were 0.22, 0.33, 0.28, 0.36, and 0.37, respectively. The Akaike information criterion of BMO-MRW showed the smallest values in analyses of both threshold of visual sensitivity and total deviation. The present results show that RNFL-T volume and BMO-MRW volume were more strongly correlated with total deviation than BMO-MRW, but BMO-MRW appeared to be the best predictor of the two glaucomatous visual field indices.
关键词： retinal nerve fiber layer thickness,rim area,visual field,glaucoma,spectral domain optical coherence tomography,Bruch’s membrane opening-minimum rim width
更新于2025-09-04 15:30:14
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Evaluation of the Structure–Function Relationship in Glaucoma Using a Novel Method for Estimating the Number of Retinal Ganglion Cells in the Human Retina
摘要： PURPOSE. We developed a simple method for estimating the number of retinal ganglion cells (RGCs) in the human retina using optical coherence tomography (OCT), compared it to a previous approach, and demonstrated its potential for furthering our understanding of the structure–function relationship in glaucoma. METHODS. Swept-source (ss) OCT data and 10-2 visual ?elds (VFs) were obtained from 43 eyes of 36 healthy controls, and 50 eyes of 50 glaucoma patients and suspects. Using estimates of RGC density from the literature and relatively few assumptions, estimates of the number of RGCs in the macula were obtained based on ssOCT-derived RGC layer thickness measurements. RESULTS. The RGC estimates were in general agreement with previously published values derived from histology, whereas a prior method based on VF sensitivity did not agree as well with histological data and had signi?cantly higher (P ? 0.001) and more variable (P < 0.001) RGC estimates than the new method based on ssOCT. However, the RGC estimates of the new approach were not zero for extreme VF losses, suggesting that a residual, non-RGC contribution needs to be added. Finally, the new ssOCT-derived RGC estimates were signi?cantly (P < 0.001 to P ? 0.018) related to VF sensitivity (Spearman’s q ? 0.26–0.47), and, in contrast to claims made in prior studies, statistically signi?cant RGC loss did not occur more often than statistically signi?cant visual loss. CONCLUSIONS. The novel method for estimating RGCs yields values that are closer to histological estimates than prior methods, while relying on considerably fewer assumptions. Although the value added for clinical applications is yet to be determined, this approach is useful for assessing the structure–function relationship in glaucoma.
关键词： visual ?elds,glaucoma,retinal ganglion cells,structure versus function,macula,optical coherence tomography
更新于2025-09-04 15:30:14
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Shape Changes of the Anterior Lamina Cribrosa in Normal, Ocular Hypertensive, and Glaucomatous Eyes Following Acute Intraocular Pressure Elevation
摘要： PURPOSE. The purpose of this study was to estimate and compare changes in anterior lamina cribrosa (LC) morphology in normal, ocular hypertensive (OHT), and glaucomatous eyes following acute elevations in intraocular pressure (IOP). METHODS. The optic nerve heads (ONHs) of 97 subjects (17 OHT, 19 primary open-angle glaucoma [POAG], 31 primary angle-closure glaucoma [PACG], and 30 normal subjects) were imaged using optical coherence tomography (OCT). Intraocular pressure was raised twice by applying forces to the anterior sclera, using an ophthalmodynamometer. After each IOP elevation, IOP was held constant and measured; each ONH was rescanned with OCT. In each OCT volume, the anterior LC was enhanced, delineated, and its global shape index (GSI) calculated and compared across groups. RESULTS. The baseline IOP was 17.5 6 3.5 mm Hg and was increased to 38 6 5.9 mm Hg and then to 46.5 6 5.9 mm Hg. At the ?rst IOP increment, mean GSI was signi?cantly smaller than that at baseline in normal subjects and glaucoma subjects (P < 0.05) but not in OHT subjects (P ? 0.12). For the second IOP increment, the mean GSI was signi?cantly smaller than that at baseline in normal subjects and in OHT eyes (P < 0.05). After adjusting for age, sex, and baseline IOP, the LC of POAG eyes was found to be signi?cantly more posteriorly curved than that of normal subjects (P ? 0.04). CONCLUSIONS. Acute IOP elevations altered anterior LC shape in a complex nonlinear fashion. The LC of POAG eyes was more cupped following acute IOP elevations compared to that of normal subjects.
关键词： morphometry,glaucoma,elevation,global shape index,intraocular pressure,lamina cribrosa,adaptive compensation
更新于2025-09-04 15:30:14
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Cross-Sectional Imaging Analysis of Epiretinal Membrane Involvement in Unilateral Open-Angle Glaucoma Severity
摘要： PURPOSE. To determine the relevance of epiretinal membranes (ERMs) in primary open-angle glaucoma (POAG) and potential risk for glaucoma severity. METHODS. Sixty eyes of 30 patients with POAG who had a unilateral ERM were analyzed; 60 nonglaucomatous eyes of 30 patients with a unilateral ERM also were recruited in this institutional cross-sectional study. Patients underwent swept-source (SS) optical coherence tomography (OCT) imaging and visual ?eld testing. Intraindividual differences in the SS-OCT retinal nerve ?ber layer (RNFL) disc cupping area measurements and visual ?eld outcomes were analyzed in the two groups. RESULTS. In patients with POAG, the mean circumpapillary RNFL thickness in the eyes with an ERM was 75.6 6 16.5 lm superiorly and 71.8 6 26.0 inferiorly compared with the fellow eyes without an ERM (87.2 6 23.6 lm, P ? 0.0061 and 81.3 6 27.7 lm, P ? 0.034, respectively). The areas of disc cupping and cup-to-disc ratio seen on OCT horizontal and vertical B-scans were larger in eyes with an ERM than in the fellow eyes without ERM (P ? 0.0004 and P ? 0.0011, respectively). The average mean deviations were (cid:2)11.6 6 7.5 dB in the ERM group and (cid:2)8.19 6 6.4 dB in the group with no ERM (P ? 0.029). Eyes with an ERM received more antiglaucoma eye drops (P ? 0.018). Those differences were not seen between eyes with an ERM or fellow eyes in patients without glaucoma. CONCLUSIONS. The presence of an ERM can be a potential risk factor for unilateral severity in eyes with POAG.
关键词： epiretinal membrane,glaucoma,inner retina
更新于2025-09-04 15:30:14
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Development of Visual Field Screening Procedures: A Case Study of the Octopus Perimeter
摘要： Purpose: We develop a methodology for designing perimetric screening procedures, using Octopus perimeters as a case study. Methods: The process has three stages: analytically determining specificity and number of presentations required for different multisampling suprathreshold schemes at a single location of the visual field, ranking visual field locations by their positive predictive value (PPV) for glaucoma, and determining a pass/fail criteria for the test. For the case study the Octopus G-program visual field test pattern is used, and a dataset of 385 glaucoma and 86 normal patients. Results: Using a 1-of-3 sampling strategy at a level equal to the 95 percentile of normal observers gave the most robust specificity under the influences of false-negative responses using an average of 1.5 presentations per location. The PPV analysis gave 19 locations that completely classified our glaucomatous data. A further 9 points were added to screen for nonglaucomatous loss. The final stage found that insisting that 3 locations are missed for the screening to fail gave a simulated specificity and sensitivity of approximately 95% for unreliable responders. Conclusions: Our method gives a principled approach to choosing between the many parameters of a visual field screening procedure. We have developed a procedure for the Octopus that should terminate in less than 1 minute for normal observers with high specificity and sensitivity to glaucoma. Translational Relevance: Visual field screening is used in community settings and eye care practice. This study provides a principled approach to the development of such screening procedures and details a new procedure.
关键词： screening,glaucoma,visual field
更新于2025-09-04 15:30:14