Detection Of Glaucoma Progression Research Articles

How to evaluate structure in glaucomas?

AbstractThis course is designed for young ophthalmologists and will give the opportunity to discuss aspects of the structure and structural changes of the optic nerve head and the retinal nerve fiber layer related to glaucoma and the alteration of the visual function related to this disease. In the last few years there is increasing evidence of the importance of structural measurements particularly early in the disease, and combining information from structure and function can significantly improve detection and assessment of glaucoma progression. Different tools and new technologies for measuring structural changes will be discussed in details such as stereo‐ photographs, HRT, GDx and OCT.

Comparison of Event-Based Methods Using Optical Coherence Tomography and Automated Perimetry to Detect the Progression of Glaucoma in Patients with Open-Angle Glaucoma

Background/Aims: To compare event-based methods for estimating the incidence of glaucoma progression using optical coherence tomography (OCT) and automated perimetry and to assess agreement between structural and functional tests for detecting glaucoma progression. Methods: Functional progression of glaucoma was estimated by guided progression analysis (GPA) using a Humphrey field analyzer (HFA), and structural progression was assessed by OCT and defined as the decrease in retinal nerve fiber layer thickness based on test-retest variability data of previous reports on clock-hour and quadrant maps. The level of agreement between structural and functional progression was evaluated using kappa statistics. Results: Fifty eyes of 50 patients with open-angle glaucoma were enrolled in this retrospective study. The incidence of visual field progression estimated by GPA was 18%. The occurrence of structural progression assessed by OCT ranged from 18 to 68%. The more stringent OCT progression criterion using a quadrant map showed the best agreement with HFA GPA (ĸ = 0.423) and detected perimetric progression with high specificity, while the less stringent OCT criterion considering any clock hour showed the lowest agreement with functional progression (ĸ = 0.098). Conclusion: OCT progression criteria based on test-retest variability showed moderate agreement with perimetric progression, and more stringent criteria showed better agreement with functional progression than less stringent ones.

Longitudinal Structure-Function Relationships With Scanning Laser Ophthalmoscopy and Standard Achromatic Perimetry

To explore longitudinal correlations between structural and functional rates of glaucoma progression with confocal scanning laser ophthalmoscopy and standard achromatic perimetry. In this retrospective longitudinal study, 108 eyes with suspected or established glaucoma and 5 or more good-quality scanning laser ophthalmoscopy examinations (global pixel SD<50 μm) and 6 or more reliable visual field (VF) examinations were included. Global and regional rates of progression for VF sensitivity and rim area (RA) were calculated with linear regression analysis. Correlations of global and regional rates of progression were calculated with bivariate correlation analyses. Linear mixed models were built to determine predictive factors for functional and structural changes over time. The mean (SD) baseline mean deviation was -4.6 (4.9) decibels. The inferotemporal and superotemporal RAs had the highest overall rates of decay (0.0018 mm2/y). Glaucoma progressed in 38 (35.2%) and 20 (18.5%) eyes based on event and trend mean deviation criteria, respectively. The highest correlations of rates were observed between the superonasal or superotemporal RA and inferior VF clusters (ρ=0.25-0.39; P≤.03). Follow-up time, baseline RA, and their interaction were the only significant predictors for RA change; belonging to the group with progression was not associated with higher rates of RA progression. Longitudinal structure-function relationships are fair at best in eyes with suspected or established glaucoma. Eyes with progressing disease according to VF criteria do not show significantly higher rates of RA progression. Both structural and functional outcomes need to be monitored to detect glaucoma progression in a timely manner.

Detection of Glaucoma Progression by Assessment of Segmented Macular Thickness Data Obtained Using Spectral Domain Optical Coherence Tomography

We evaluated the clinical use of segmented macular layer thickness measurement in terms of glaucoma diagnosis and the ability to detect progression, and to compare such outcomes to those by circumpapillary retinal nerve fiber layer (cRNFLT) and total macular thickness (TMT) measurements. The study included 141 glaucomatous and 61 healthy eyes. All glaucomatous eyes were subjected to at least four spectral domain optical coherence tomography (SD-OCT) examinations (mean follow-up, 2.13 years). Segmented macular layers were the macular nerve fiber layer (NFL), ganglion cell and inner plexiform layer (GCA), and outer retinal layer (ORL; from outer plexiform layer to retinal pigment epithelium). Areas under receiver operating characteristic curves (AUCs) discriminating healthy from glaucomatous eyes were determined in baseline measurements. The sensitivity and specificity of these parameters in terms of glaucoma progression detection were determined, with reference to assessment of optic disc/retinal nerve fiber layer (RNFL) photographs/visual field (VF) deterioration as standard(s). GCA afforded the best diagnostic performance among three macular layers. The AUC of the GCA thickness (GCAT) was less than that of cRNFLT (0.869 vs. 0.953, P = 0.018), but superior to that of TMT (0.790, P = 0.05). Of the eyes, 38 showed progression during follow-up by standard The sensitivities of TMT, GCAT, and cRNFLT values in terms of detection of progression were 14%, 8%, and 5%, respectively. Although baseline cRNFL measurement was optimal in terms of glaucoma diagnosis, the GCAT and TMT showed similar levels of sensitivity in progression detection.

Pointwise Rates of Visual Field Progression Cluster according to Retinal Nerve Fiber Layer Bundles

To explore whether pointwise rates of visual field progression group together in patterns consistent with retinal nerve fiber layer (RNFL) bundles. Three hundred eighty-nine eyes of 309 patients from the Advanced Glaucoma Intervention Study with ≥6 years of follow-up and ≥12 reliable visual field exams were selected. Linear and exponential regression models were used to estimate pointwise rates of change over time. Clustering of pointwise rates of progression was investigated with hierarchical cluster analysis using Pearson's correlation coefficients as distance measure and an average linkage scheme for building the hierarchy with cutoff value of r > 0.7. The average mean deviation (±SD) was -10.9 (±5.4). The average (±SD) follow-up time and number of visual field exams were 8.1 (±1.1) years and 15.7 (±3.0), respectively. Pointwise rates of progression across the visual field grouped into clusters consistent with anatomic patterns of RNFL bundles with both linear (10 clusters) and exponential (six clusters) regression models. One hundred forty-four (37%) eyes progressed according to the two-omitting pointwise linear regression model. ointwise rates of change in glaucoma patients cluster into regions consistent with RNFL bundle patterns. This finding validates the clinical significance of such pointwise rates. The correlations among pointwise rates of change can be used for spatial filtering purposes, facilitating detection or prediction of glaucoma progression.

Glaucoma Progression Detection by Retinal Nerve Fiber Layer Measurement Using Scanning Laser Polarimetry: Event and Trend Analysis

PurposeTo evaluate the use of scanning laser polarimetry (SLP, GDx VCC) to measure the retinal nerve fiber layer (RNFL) thickness in order to evaluate the progression of glaucoma.MethodsTest-retest measurement variability was determined in 47 glaucomatous eyes. One eye each from 152 glaucomatous patients with at least 4 years of follow-up was enrolled. Visual field (VF) loss progression was determined by both event analysis (EA, Humphrey guided progression analysis) and trend analysis (TA, linear regression analysis of the visual field index). SLP progression was defined as a reduction of RNFL exceeding the predetermined repeatability coefficient in three consecutive exams, as compared to the baseline measure (EA). The slope of RNFL thickness change over time was determined by linear regression analysis (TA).ResultsTwenty-two eyes (14.5%) progressed according to the VF EA, 16 (10.5%) by VF TA, 37 (24.3%) by SLP EA and 19 (12.5%) by SLP TA. Agreement between VF and SLP progression was poor in both EA and TA (VF EA vs. SLP EA, k = 0.110; VF TA vs. SLP TA, k = 0.129). The mean (±standard deviation) progression rate of RNFL thickness as measured by SLP TA did not significantly differ between VF EA progressors and non-progressors (-0.224 ± 0.148 µm/yr vs. -0.218 ± 0.151 µm/yr, p = 0.874). SLP TA and EA showed similar levels of sensitivity when VF progression was considered as the reference standard.ConclusionsRNFL thickness as measurement by SLP was shown to be capable of detecting glaucoma progression. Both EA and TA of SLP showed poor agreement with VF outcomes in detecting glaucoma progression.

Progression detection in different stages of glaucoma: mean deviation versus visual field index

We evaluated and compared visual field index (VFI) and mean deviation (MD) capacity in detecting glaucoma progression at different stages. Participants were classified as having early-, moderate-, or advanced-stage glaucoma. Trend-based approaches (TA) using linear regression analysis of the VFI and MD (VFI TA, MD TA) over patient age were performed. The rate was determined by both approaches at different stages of glaucoma. We analyzed 173 eyes of 173 participants (mean follow-up 6.2 years). Glaucoma progressed in 24 eyes (13.9%) as determined by VFI TA and in 21 eyes (12.1%) as determined by MD TA. Agreement between VFI TA and MD TA was moderate to good (κ = 0.617). The rate was -0.29 ± 2.31 dB per year as determined by MD TA and 1.25 ± 4.79% per year as determined by VFI TA. Progression rate according to glaucoma severity was not significantly different among subgroups when assessed by both trend-based approaches. VFI TA and MD TA performed similarly in measuring different stages of glaucoma progression. However, VFI TA and MD TA did not have agree perfectly in glaucoma progression detection. As glaucomatous changes can be general or localized, we suggest that changes in the MD and VFI should be considered when monitoring glaucoma progression through all stages.

Influence of Visual Field Testing Frequency on Detection of Glaucoma Progression With Trend Analyses

To explore whether increased frequency of visual field testing leads to earlier detection of glaucoma progression with trend analyses. The visual fields of 468 eyes (381 patients) from the Advanced Glaucoma Intervention Study with 10 or more reliable visual field tests and 3 or more years of follow-up were studied. Starting at year 1, every other visual field examination was deleted to create a low-frequency data set, and the original group was kept as the high-frequency data set. The proportion of progressing eyes and the time to progression were compared between the 2 data sets with global and pointwise linear regression criteria. The median number of visual field examinations was 20 and 12 for the high- and low-frequency data sets, respectively. Based on primary mean deviation criteria, 204 eyes (43.6%) in the high-frequency data set and 160 eyes (34.2%) in the low-frequency data set progressed (P<.001), whereas 185 eyes (39.5%) in the high-frequency data set and 167 eyes (35.7%) in the low-frequency data set progressed according to pointwise linear regression (P=.02). The high-frequency data set was more likely to detect progression with mean deviation (hazard ratio [HR], 1.69 [95% confidence interval {CI}, 1.36-2.10]) or pointwise linear regression criteria (HR, 1.52 [95% CI, 1.21-1.90]). A similar number of improving eyes were detected with mean deviation criteria (HR, 0.95 [95% CI, 0.58-1.60]), but pointwise linear regression criteria were more likely to detect improvement in the high-frequency data set (HR, 2.27 [95% CI, 1.43-3.62]). The results did not significantly change after censoring data at 5 years. Increasing the frequency of visual field testing leads to earlier detection of glaucoma progression, especially with global trend analyses. This finding has significant implications for the care of patients with glaucoma.

Combining Structural and Functional Measurements to Improve Detection of Glaucoma Progression using Bayesian Hierarchical Models

To present and evaluate a new methodology for combining longitudinal information from structural and functional tests to improve detection of glaucoma progression and estimation of rates of change. This observational cohort study included 434 eyes of 257 participants observed for an average of 4.2 ± 1.1 years and recruited from the Diagnostic Innovations in Glaucoma Study (DIGS). The subjects were examined annually with standard automated perimetry, optic disc stereophotographs, and scanning laser polarimetry with enhanced corneal compensation. Rates of change over time were measured using the visual field index (VFI) and average retinal nerve fiber layer thickness (TSNIT average). A bayesian hierarchical model was built to integrate information from the longitudinal measures and classify individual eyes as progressing or not. Estimates of sensitivity and specificity of the bayesian method were compared with those obtained by the conventional approach of ordinary least-squares (OLS) regression. The bayesian method identified a significantly higher proportion of the 405 glaucomatous and suspect eyes as having progressed when compared with the OLS method (22.7% vs. 12.8%; P < 0.001), while having the same specificity of 100% in 29 healthy eyes. In addition, the bayesian method identified a significantly higher proportion of eyes with progression by optic disc stereophotographs compared with the OLS method (74% vs. 37%; P = 0.001). A bayesian hierarchical modeling approach for combining functional and structural tests performed significantly better than the OLS method for detection of glaucoma progression. (ClinicalTrials.gov number, NCT00221897.).

Clinical Use of OCT in Assessing Glaucoma Progression

Detection of disease progression is an important and challenging component of glaucoma management. Optical coherence tomography (OCT) has proved to be valuable in the detection of glaucomatous damage. With its high resolution and proven measurement reproducibility, OCT has the potential to become an important tool for glaucoma progression detection. This manuscript presents the capabilities of the OCT technology pertinent for detection of progressive glaucomatous damage and provides a review of the current knowledge on the device's clinical performance.

Evaluation of Retinal Nerve Fiber Layer Progression in Glaucoma: A Comparison between the Fast and the Regular Retinal Nerve Fiber Layer Scans

To compare the performance of the fast (256 A-scans in each scan circle) and the regular (512 A-scans in each scan circle) retinal nerve fiber layer (RNFL) scan protocols for detection of glaucoma progression using the Stratus optical coherence tomography (OCT) device (Carl Zeiss Meditec, Dublin, CA). Retrospective, longitudinal study. One hundred twenty-nine eyes from 72 glaucoma patients. All patients had been followed up for 2.9 to 6.1 years with a median follow-up of 4 months. All eyes had at least 4 serial RNFL measurements obtained with both the fast and the regular RNFL scans. Visual field (VF) assessment was performed on the same day as RNFL imaging. Retinal nerve fiber layer thickness and VF progression were evaluated with linear regression analysis against age. The mean rate of average RNFL thickness reduction was estimated with linear mixed modeling. The agreement of progression detection and the rate of change of RNFL thicknesses. A total of 1373 fast and 1373 regular RNFL scans and 1236 VF tests were analyzed. With reference to the average RNFL thickness, the fast RNFL scan detected more eyes with progression (21 eyes from 19 patients vs. 15 eyes from 13 patients) than the regular scan at a comparable level of specificity (96.9% vs. 96.1%). More eyes were found to have increasing RNFL thickness with age at individual clock hours (except for 3, 5, 6, and 11 o'clock) when the measurements were obtained with the regular scan. The agreement between the fast and the regular scan for detection of RNFL progression was fair to moderate, with κ values ranging between 0.14 and 0.49. The rate of average RNFL thickness progression was -1.01 μm per year for the fast RNFL scan and -0.77 μm per year for the regular scan. The choice of scan protocols in the Stratus OCT has a significant impact in the evaluation of RNFL progression. The fast RNFL scan seems to be preferable to follow RNFL damage in glaucoma.

A Review of Current Technology Used in Evaluating Visual Function in Glaucoma

Glaucoma is a blinding disease associated with characteristic progressive optic nerve damage and visual field loss. Visual field testing in the form of automated perimetry is critical in the clinical diagnosis and monitoring of glaucoma. Functional tests can also be powerful research tools in clinical trials and in the field of neuroprotection. Standard automated perimetry (SAP) commonly used today, however, has its limitations. Early diagnosis of glaucoma based on functional measures can be challenging since it has been shown that retinal ganglion cell loss precedes defects detected on SAP. In addition, SAP is a subjective test prone to inter-test variability making the evaluation of disease progression problematic. Newer algorithms and functional tests are now being used and developed in an attempt to improve the accuracy in the detection of glaucoma and disease progression.

Detecting glaucomatous progression using GDx with variable and enhanced corneal compensation using Guided Progression Analysis

ObjectiveTo compare detection of glaucoma progression with scanning laser polarimetry using two methods for corneal compensation.MethodsNormal, glaucoma suspects and glaucoma patients with 36 months' follow-up meeting the eligibility criteria were...

Agreement for Detecting Glaucoma Progression with the GDx Guided Progression Analysis, Automated Perimetry, and Optic Disc Photography

To evaluate the ability of the GDx Variable Corneal Compensation (VCC) Guided Progression Analysis (GPA) software for detecting glaucomatous progression. Observational cohort study. The study included 453 eyes from 252 individuals followed for an average of 46+/-14 months as part of the Diagnostic Innovations in Glaucoma Study. At baseline, 29% of the eyes were classified as glaucomatous, 67% of the eyes were classified as suspects, and 5% of the eyes were classified as healthy. Images were obtained annually with the GDx VCC and analyzed for progression using the Fast Mode of the GDx GPA software. Progression using conventional methods was determined by the GPA software for standard automated achromatic perimetry (SAP) and by masked assessment of optic disc stereophotographs by expert graders. Sensitivity, specificity, and likelihood ratios (LRs) for detection of glaucoma progression using the GDx GPA were calculated with SAP and optic disc stereophotographs used as reference standards. Agreement among the different methods was reported using the AC(1) coefficient. Thirty-four of the 431 glaucoma and glaucoma suspect eyes (8%) showed progression by SAP or optic disc stereophotographs. The GDx GPA detected 17 of these eyes for a sensitivity of 50%. Fourteen eyes showed progression only by the GDx GPA with a specificity of 96%. Positive and negative LRs were 12.5 and 0.5, respectively. None of the healthy eyes showed progression by the GDx GPA, with a specificity of 100% in this group. Inter-method agreement (AC(1) coefficient and 95% confidence intervals) for non-progressing and progressing eyes was 0.96 (0.94-0.97) and 0.44 (0.28-0.61), respectively. The GDx GPA detected glaucoma progression in a significant number of cases showing progression by conventional methods, with high specificity and high positive LRs. Estimates of the accuracy for detecting progression suggest that the GDx GPA could be used to complement clinical evaluation in the detection of longitudinal change in glaucoma.

Detection of Glaucoma Progression with Stratus OCT Retinal Nerve Fiber Layer, Optic Nerve Head, and Macular Thickness Measurements

To evaluate and compare the ability of optical coherence tomography (OCT) retinal nerve fiber layer (RNFL), optic nerve head, and macular thickness parameters to detect progressive structural damage in glaucoma. This observational cohort study included 253 eyes of 253 patients. Images were obtained annually with the Stratus OCT (Carl Zeiss Meditec, Inc., Dublin, CA) along with optic disc stereophotographs and standard automated perimetry (SAP) visual fields. The median follow-up time was 4.01 years. Progression was determined by the Guided Progression Analysis software for SAP (Carl Zeiss Meditec, Inc.) and by masked assessment of optic disc stereophotographs performed by expert graders. Random coefficient models and receiver operating characteristic (ROC) curves were used to evaluate the relationship between change in Stratus OCT parameters over time and progression as determined by SAP and/or stereophotographs. From the 253 eyes, 31 (13%) showed progression over time by stereophotographs and/or SAP. Mean rates of change in average RNFL thickness were significantly higher for progressors compared with nonprogressors (-0.72 mum/y vs. 0.14 mum/y; P = 0.004), with sensitivity of 77% for specificity of 80%. RNFL parameters performed significantly better than ONH and macular thickness measurements in discriminating progressors from nonprogressors. The parameters with the largest ROC curve areas for each scanning area were inferior RNFL thickness (0.84), cup area (0.66), and inferior inner macula thickness (0.64). Stratus OCT RNFL parameters discriminated between eyes progressing by visual fields or optic disc photographs and eyes that remained stable by these methods and performed significantly better than ONH and macular thickness parameters in detecting change over time.

Impact of Atypical Retardation Patterns on Detection of Glaucoma Progression using the GDx with Variable Corneal Compensation

To evaluate the impact of atypical retardation patterns (ARP) on detection of progressive retinal nerve fiber layer (RNFL) loss using scanning laser polarimetry with variable corneal compensation (VCC). Observational cohort study. The study included 377 eyes of 221 patients with a median follow-up of 4.0 years. Images were obtained annually with the GDx VCC (Carl Zeiss Meditec Inc, Dublin, California, USA), along with optic disc stereophotographs and standard automated perimetry (SAP) visual fields. Progression was determined by the Guided Progression Analysis software for SAP and by masked assessment of stereophotographs by expert graders. The typical scan score (TSS) was used to quantify the presence of ARPs on GDx VCC images. Random coefficients models were used to evaluate the relationship between ARP and RNFL thickness measurements over time. Thirty-eight eyes (10%) showed progression over time on visual fields, stereophotographs, or both. Changes in TSS scores from baseline were significantly associated with changes in RNFL thickness measurements in both progressing and nonprogressing eyes. Each 1-unit increase in TSS score was associated with a 0.19-microm decrease in RNFL thickness measurement (P < .001) over time. ARPs had a significant effect on detection of progressive RNFL loss with the GDx VCC. Eyes with large amounts of atypical patterns, great fluctuations on these patterns over time, or both may show changes in measurements that can appear falsely as glaucomatous progression or can mask true changes in the RNFL.

Performance of glaucoma progression analysis software in a glaucoma population

To compare visual field progression in glaucoma patients assessed by the glaucoma progression analysis (GPA) used in the Humphrey Field Analyzer perimeter and by objective clinical criteria. Retrospective cross-sectional study of 93 eyes of 93 consecutive glaucoma patients with at least five reliable visual fields. Progression of the visual field damage was analyzed by a masked observer using both GPA and defined clinical criteria. Prevalence of progressive visual field damage was determined by clinical criteria and GPA analysis. Agreement between both methods was quantified by kappa analysis. GPA performance was also calculated using clinical criteria analysis as the reference standard. The prevalence of progressive visual field damage was 30% and 29% with GPA evaluation and clinical criteria analysis respectively. Where two consecutive visual fields showing progressive damage were needed to confirm progression, the kappa index of agreement between these two approaches was 0.87 +/- 0.06 (mean +/- standard error of the mean). Where three consecutive fields showing progressive damage were required, the kappa index of agreement was 0.64 +/- 0.1. The GPA performance showed a sensitivity and specificity of 93% (95% CI, 83-100%) and 95% (95% CI, 90-100%) respectively, and a positive likelihood ratio of 20 if the two consecutive visual fields criterion was used. The performance was worse if three consecutive progressing visual fields were required to confirm progression. There is a strong correlation between GPA identification of glaucomatous progression and a thorough objective clinical assessment of the visual fields. GPA could be a useful test to aid clinicians in the detection of glaucomatous progression, with high specificity, strong positive likelihood ratio, and good sensitivity and negative likelihood ratio.

Ability of Stratus OCT to Detect Progressive Retinal Nerve Fiber Layer Atrophy in Glaucoma

To evaluate the ability of Stratus optical coherence tomography (OCT version 4.0; Carl Zeiss Meditec, Inc., Dublin, CA) to detect progressive glaucomatous retinal nerve fiber layer (RNFL) atrophy observed by red-free RNFL photography. Intersession test-retest variability of each clock hour, quadrant, and average RNFL thickness was determined in 53 control subjects. The sensitivity and specificity of OCT for identification of progressive RNFL atrophy were tested on subjects in whom this condition was clearly observed in red-free RNFL photographs (n=27) and in another control group (n=62), according to criteria derived from test-retest variability. The sensitivity of Stratus OCT RNFL measurement ranged from 14.8% (for average RNFL thickness) to 85.2% (for clock hour thickness) when tested at the 95% confidence level. The specificity of Stratus OCT RNFL measurement was approximately 95% for average RNFL thickness, but decreased considerably with clock hour (59.7%) and quadrant thickness (77.4%). This is presumably because multiple testing was used for multiple clock hours and quadrants. When calculated based on two consecutive follow-up examinations, the specificity for the clock hour measurements increased to 86.6% and that for quadrant thickness increased to 92.5%. The OCT-measured RNFL thickness change showed excellent topographic agreement with the progressive RNFL atrophy observed using RNFL photography. Within the limits of retest variability, Stratus OCT detects progressive RNFL atrophy with high sensitivity and moderate specificity in cases showing localized progressive loss of retinal nerve fibers in red-free photographs. The specificity can be improved by use of multiple measurements. Stratus OCT is a potentially useful technique for detection of glaucoma progression.

Measurement Variability in Heidelberg Retina Tomograph Imaging of Neuroretinal Rim Area

To investigate the optimal frequency of imaging during follow-up to detect glaucoma progression by characterizing variability (noise) in neuroretinal rim area (RA) measured by Heidelberg Retina Tomograph (HRT; Heidelberg Engineering, Heidelberg, Germany). RA noise was estimated from patient data and characterized by fitting theoretical distributions to the observed data. Multilevel regression was used to determine factors that significantly affect noise. Computer simulations of disease progression were performed by adding noise generated from the distribution derived from the observed data to the average rate of loss in RA estimated from longitudinal data. Rates of detection of disease progression were investigated for various progression rates, follow-up periods, and rates of imaging. Noise was not normally distributed and was best characterized by the hyperbolic distribution, which fit averages well while allowing for extreme values. Noise was greatly influenced by image quality, but age did not have a significant effect. Rates of detection improved for more frequent imaging, better quality images, and faster rates of disease progression. Noise in HRT measurement of RA is well characterized by the hyperbolic distribution. Sensitivity of detection improves with more frequent testing, but if consistently poor-quality images are yielded for a patient, the probability of detection is low. Results from this work could be used to tailor individual follow-up patterns for patients with different rates of RA loss and image quality, especially in a clinical trial setting.

Update prospektiver Glaukomstudien

Previously published prospective therapeutic intervention studies in ocular hypertension and glaucoma are summarized. The concept of intraocular pressure reduction was evaluated in normal tension glaucoma ["Early manifest glaucoma trial (EMGT)"], the "Collaborative normal-tension glaucoma study (CNTGS)" and ocular hypertension ["Ocular hypertensive study (OHTS)" as well as the "European glaucoma prevention study (EGPS)"]. Early open angle glaucoma patients were included in the EMGT trial as well as the "Collaborative initial glaucoma treatment study (CIGTS)", whereas advanced glaucoma patients were examined in the "Advanced glaucoma intervention study (AGIS)". The study design, the results and the conclusions will be highlighted in the text. The therapeutic concept of intraocular pressure reduction decreases the risk of progression by 50 % in normal tension glaucoma, ocular hypertension and early open angle glaucoma. The mean pressure reduction to 12 mmHg in advanced glaucoma abolished visual field progression. The natural course of the disease documented by the control groups is now known. Sensitive glaucoma progression detection is clinically available by glaucoma change probability maps (Humphrey-full threshold perimetry) used in the EMGT.