Standard Automated Perimetry Visual Field Research Articles

Mapping Visual Field Defects With fMRI - Impact of Approach and Experimental Conditions.

Current initiatives to restore vision emphasize the need for objective assessments of visual field (VF) defects as pursued with functional magnetic resonance imaging (fMRI) approaches. Here, we compared population receptive field (pRF) mapping-based VF reconstructions to an fMRI method that uses more robust visual stimulation (on-off block design) in combination with individualized anatomy-driven retinotopic atlas-information (atlas-based VF). We investigated participants with sizable peripheral VF-deficits due to advanced glaucoma (n = 4) or retinitis pigmentosa (RP; n = 2) and controls (n = 6) with simulated scotoma. We obtained (1) standard automated perimetry (SAP) data as reference VFs and 3T fMRI data for (2) pRF-mapping [8-direction bar stimulus, fixation color change task] and (3) block-design full-field stimulation [8-direction drifting contrast patterns during (a) passive viewing (PV) and (b) one-back-task (OBT; reporting successions of identical motion directions) to probe the impact of previously reported task-related unspecific visual cortex activations]. Correspondence measures between the SAP and fMRI-based VFs were accuracy, assisted by sensitivity and specificity. We found an accuracy of pRF-based VF from V1 in patients [median: 0.62] that was similar to previous reports and increased by adding V2 and V3 to the analysis [0.74]. In comparison to the pRF-based VF, equivalent accuracies were obtained for the atlas-based VF for both PV [0.67] and, unexpectedly, the OBT [0.59], where, however, unspecific cortical activations were reflected by a reduction in sensitivity [0.71 (PV) and 0.35 (OBT)]. In conclusion, in patients with peripheral VF-defects, we demonstrate that previous fMRI procedures to obtain VF-estimates might be enhanced by: (1) pooling V1-V3 to enhance accuracy; (2) reporting sensitivity and specificity measures to increase transparency of the VF-reconstruction metric; (3) applying atlas-based procedures, if pRF-based VFs are not available or difficult to obtain; and (4) giving, counter-intuitively, preference to PV. These findings are expected to provide guidance to overcome current limitations of translating fMRI-based methods to a clinical work-up.

RetiNerveNet: using recursive deep learning to estimate pointwise 24-2 visual field data based on retinal structure

Glaucoma is the leading cause of irreversible blindness in the world, affecting over 70 million people. The cumbersome Standard Automated Perimetry (SAP) test is most frequently used to detect visual loss due to glaucoma. Due to the SAP test’s innate difficulty and its high test-retest variability, we propose the RetiNerveNet, a deep convolutional recursive neural network for obtaining estimates of the SAP visual field. RetiNerveNet uses information from the more objective Spectral-Domain Optical Coherence Tomography (SDOCT). RetiNerveNet attempts to trace-back the arcuate convergence of the retinal nerve fibers, starting from the Retinal Nerve Fiber Layer (RNFL) thickness around the optic disc, to estimate individual age-corrected 24-2 SAP values. Recursive passes through the proposed network sequentially yield estimates of the visual locations progressively farther from the optic disc. While all the methods used for our experiments exhibit lower performance for the advanced disease group (possibly due to the “floor effect” for the SDOCT test), the proposed network is observed to be more accurate than all the baselines for estimating the individual visual field values. We further augment the proposed network to additionally predict the SAP Mean Deviation values and also facilitate the assignment of higher weightage to the underrepresented groups in the data. We then study the resulting performance trade-offs of the RetiNerveNet on the early, moderate and severe disease groups.

Structure-function relationship in a series of glaucoma cases

To map retinal sensitivity and peripapillary retinal nerve fiber layer (RNFL) thickness, as measured by standard automated perimetry (SAP) and optical coherence tomography (OCT) respectively, in patients with various stages of primary open-angle glaucoma (POAG). Ninety patients with POAG were prospectively selected for SAP and for OCT RNFL thickness measurements. Factorial analysis performed independently for each hemifield was used to identify groups of related SAP visual field points. Pearson correlation coefficients were determined between visual field regions and peripapillary RNFL sectors and these data used to construct structure-function correlation maps for the various disease stages. Factorial analysis identified 4 factors or visual field regions for the inferior hemifield and 5 for the superior hemifield. For all patients and the subset of patients with advanced POAG, the strongest correlation was detected between the superior hemifield and the inferior RNFL sectors, while higher correlations for incipient and moderate disease stages were observed between the inferior hemifield and the superior RNFL sectors. In these patients, functional and structural damage can be mapped such that each zone of related SAP points correlates with one or several peripapillary RNFL zones. Such maps could improve our understanding of structure-function relationships in glaucoma.

Retinal Nerve Fiber Layer Features Identified by Unsupervised Machine Learning on Optical Coherence Tomography Scans Predict Glaucoma Progression.

PurposeTo apply computational techniques to wide-angle swept-source optical coherence tomography (SS-OCT) images to identify novel, glaucoma-related structural features and improve detection of glaucoma and prediction of future glaucomatous progression.MethodsWide-angle SS-OCT, OCT circumpapillary retinal nerve fiber layer (cpRNFL) circle scans spectral-domain (SD)-OCT, standard automated perimetry (SAP), and frequency doubling technology (FDT) visual field tests were completed every 3 months for 2 years from a cohort of 28 healthy participants (56 eyes) and 93 glaucoma participants (179 eyes). RNFL thickness maps were extracted from segmented SS-OCT images and an unsupervised machine learning approach based on principal component analysis (PCA) was used to identify novel structural features. Area under the receiver operating characteristic curve (AUC) was used to assess diagnostic accuracy of RNFL PCA for detecting glaucoma and progression compared to SAP, FDT, and cpRNFL measures.ResultsThe RNFL PCA features were significantly associated with mean deviation (MD) in both SAP (R2 = 0.49, P < 0.0001) and FDT visual field testing (R2 = 0.48, P < 0.0001), and with mean circumpapillary RNFL thickness (cpRNFLt) from SD-OCT (R2 = 0.58, P < 0.0001). The identified features outperformed each of these measures in detecting glaucoma with an AUC of 0.95 for RNFL PCA compared to an 0.90 for mean cpRNFLt (P = 0.09), 0.86 for SAP MD (P = 0.034), and 0.83 for FDT MD (P = 0.021). Accuracy in predicting progression was also significantly higher for RNFL PCA compared to SAP MD, FDT MD, and mean cpRNFLt (P = 0.046, P = 0.007, and P = 0.044, respectively).ConclusionsA computational approach can identify structural features that improve glaucoma detection and progression prediction.

Can Probability Maps of Swept-Source Optical Coherence Tomography Predict Visual Field Changes in Preperimetric Glaucoma?

To determine the usefulness of swept-source optical coherence tomography (SS-OCT) probability maps in detecting locations with significant reduction in visual field (VF) sensitivity or predicting future VF changes, in patients with classically defined preperimetric glaucoma (PPG). Of 43 PPG patients, 43 eyes were followed-up on every 6 months for at least 2 years were analyzed in this longitudinal study. The patients underwent wide-field SS-OCT scanning and standard automated perimetry (SAP) at the time of enrollment. With this wide-scan protocol, probability maps originating from the corresponding thickness map and overlapped with SAP VF test points could be generated. We evaluated the vulnerable VF points with SS-OCT probability maps as well as the prevalence of locations with significant VF reduction or subsequent VF changes observed in the corresponding damaged areas of the probability maps. The vulnerable VF points were shown in superior and inferior arcuate patterns near the central fixation. In 19 of 43 PPG eyes (44.2%), significant reduction in baseline VF was detected within the areas of structural change on the SS-OCT probability maps. In 16 of 43 PPG eyes (37.2%), subsequent VF changes within the areas of SS-OCT probability map change were observed over the course of the follow-up. Structural changes on SS-OCT probability maps could detect or predict VF changes using SAP, in a considerable number of PPG eyes. Careful comparison of probability maps with SAP results could be useful in diagnosing and monitoring PPG patients in the clinical setting.

Predicting Risk of Motor Vehicle Collisions in Patients with Glaucoma: A Longitudinal Study.

PurposeTo evaluate the ability of longitudinal Useful Field of View (UFOV) and simulated driving measurements to predict future occurrence of motor vehicle collision (MVC) in drivers with glaucoma.DesignProspective observational cohort study.Participants117 drivers with glaucoma followed for an average of 2.1 ± 0.5 years.MethodsAll subjects had standard automated perimetry (SAP), UFOV, driving simulator, and cognitive assessment obtained at baseline and every 6 months during follow-up. The driving simulator evaluated reaction times to high and low contrast peripheral divided attention stimuli presented while negotiating a winding country road, with central driving task performance assessed as “curve coherence”. Drivers with MVC during follow-up were identified from Department of Motor Vehicle records.Main Outcome MeasuresSurvival models were used to evaluate the ability of driving simulator and UFOV to predict MVC over time, adjusting for potential confounding factors.ResultsMean age at baseline was 64.5 ± 12.6 years. 11 of 117 (9.4%) drivers had a MVC during follow-up. In the multivariable models, low contrast reaction time was significantly predictive of MVC, with a hazard ratio (HR) of 2.19 per 1 SD slower reaction time (95% CI, 1.30 to 3.69; P = 0.003). UFOV divided attention was also significantly predictive of MVC with a HR of 1.98 per 1 SD worse (95% CI, 1.10 to 3.57; P = 0.022). Global SAP visual field indices in the better or worse eye were not predictive of MVC. The longitudinal model including driving simulator performance was a better predictor of MVC compared to UFOV (R2 = 0.41 vs R2 = 0.18).ConclusionsLongitudinal divided attention metrics on the UFOV test and during simulated driving were significantly predictive of risk of MVC in glaucoma patients. These findings may help improve the understanding of factors associated with driving impairment related to glaucoma.

Predicting Progression of Glaucoma from Rates of Frequency Doubling Technology Perimetry Change

To evaluate the ability of longitudinal frequency doubling technology (FDT) to predict the development of glaucomatous visual field loss on standard automated perimetry (SAP) in glaucoma suspects. Prospective, observational cohort study. The study included 587 eyes of 367 patients with suspected glaucoma at baseline selected from the Diagnostic Innovations in Glaucoma Study (DIGS) and the African Descent and Glaucoma Evaluation Study (ADAGES). These eyes had an average of 6.7 ± 1.9 FDT tests during a mean follow-up time of 73.1 ± 28.0 months. Glaucoma suspects had intraocular pressure (IOP) >21 mmHg or an optic disc appearance suspicious of glaucoma. All patients had normal or nonrepeatable abnormal SAP at baseline. Humphrey Matrix FDT (Carl Zeiss Meditec, Inc, Dublin, CA) testing was performed within 6 months of SAP testing. The study end point was the development of 3 consecutive abnormal SAP test results. Joint longitudinal survival models were used to evaluate the ability of rates of FDT pattern standard deviation (PSD) change to predict the development of visual field loss on SAP, adjusting for confounding variables (baseline age, mean IOP, corneal thickness, and follow-up measurements of SAP PSD). The R(2) index was used to evaluate and compare the predictive abilities of the model containing longitudinal FDT PSD data with the model containing only baseline data. Sixty-three of 587 eyes (11%) developed SAP visual field loss during follow-up. The mean rate of FDT PSD change in eyes that developed SAP visual field loss was 0.07 dB/year versus 0.02 dB/year in those that did not (P < 0.001). Baseline FDT PSD and slopes of FDT PSD change were significantly predictive of progression, with hazard ratios of 1.11 per 0.1 dB higher (95% confidence interval [CI], 1.04-1.18; P = 0.002) and 4.40 per 0.1 dB/year faster (95% CI, 1.08-17.96; P = 0.04), respectively. The longitudinal model performed significantly better than the baseline model with an R(2) of 82% (95% CI, 74-89) versus 11% (95% CI, 2-24), respectively. Rates of FDT PSD change were highly predictive of the development of SAP visual field loss in glaucoma suspects. This finding suggests that longitudinal FDT evaluation may be useful for risk stratification of patients with suspected glaucoma.

Comparison of visual field test results obtained through Humphrey matrix frequency doubling technology perimetry versus standard automated perimetry in healthy children

Aims:The aim of this study was to compare the visual field test results in healthy children obtained via the Humphrey matrix 24-2 threshold program and standard automated perimetry (SAP) using the Swedish interactive threshold algorithm (SITA)-Standard 24-2 test.Materials and Methods:This prospective study included 55 healthy children without ocular or systemic disorders who underwent both SAP and frequency doubling technology (FDT) perimetry visual field testing. Visual field test reliability indices, test duration, global indices (mean deviation [MD], and pattern standard deviation [PSD]) were compared between the 2 tests using the Wilcoxon signed-rank test and paired t-test. The performance of the Humphrey field analyzer (HFA) 24-2 SITA-standard and frequency-doubling technology Matrix 24-2 tests between genders were compared with Mann-Whitney U-test.Results:Fifty-five healthy children with a mean age of 12.2 ± 1.9 years (range from 8 years to 16 years) were included in this prospective study. The test durations of SAP and FDT were similar (5.2 ± 0.5 and 5.1 ± 0.2 min, respectively, P = 0.651). MD and the PSD values obtained via FDT Matrix were significantly higher than those obtained via SAP (P < 0.001), and fixation losses and false negative errors were significantly less with SAP (P < 0.05). A weak positive correlation between the two tests in terms of MD (r = 0.352, P = 0.008) and PSD (r = 0.329, P = 0.014) was observed.Conclusion:Children were able to complete both the visual test algorithms successfully within 6 min. However, SAP testing appears to be associated with less depression of the visual field indices of healthy children. FDT Matrix and SAP should not be used interchangeably in the follow-up of children.

Estimating the Rate of Retinal Ganglion Cell Loss in Glaucoma

To present and evaluate a new method of estimating rates of retinal ganglion cell (RGC) loss in glaucoma by combining structural and functional measurements. Observational cohort study. The study included 213 eyes of 213 glaucoma patients followed up for an average of 4.5 ± 0.8 years with standard automated perimetry visual fields and optical coherence tomography. A control group of 33 eyes of 33 glaucoma patients underwent repeated tests over a short period to test the specificity of the method. An additional group of 52 eyes from 52 healthy subjects followed up for an average of 4.0 ± 0.7 years was used to estimate age-related losses of RGCs. Estimates of RGC counts were obtained from standard automated perimetry and optical coherence tomography, and a weighted average was used to obtain a final estimate of the number of RGCs for each eye. The rate of RGC loss was calculated for each eye using linear regression. Progression was defined by a statistically significant slope faster than the age-expected loss of RGCs. From the 213 eyes, 47 (22.1%) showed rates of RGC loss that were faster than the age-expected decline. A larger proportion of glaucomatous eyes showed progression based on rates of RGC loss rather than based on isolated parameters from standard automated perimetry (8.5%) or optical coherence tomography (14.6%; P < .01), while maintaining similar specificities in the stable group. The rate of RGC loss estimated from combining structure and function performed better than either isolated structural or functional measures for detecting progressive glaucomatous damage.

Quantification of Visual Field Loss in Age-Related Macular Degeneration

BackgroundAn evaluation of standard automated perimetry (SAP) and short wavelength automated perimetry (SWAP) for the central 10–2 visual field test procedure in patients with age-related macular degeneration (AMD) is presented in order to determine methods of quantifying the central sensitivity loss in patients at various stages of AMD.Methods10–2 SAP and SWAP Humphrey visual fields and stereoscopic fundus photographs were collected in 27 eyes of 27 patients with AMD and 22 eyes of 22 normal subjects.ResultsMean Deviation and Pattern Standard Deviation (PSD) varied significantly with stage of disease in SAP (both p<0.001) and SWAP (both p<0.001), but post hoc analysis revealed overlap of functional values among stages. In SWAP, indices of focal loss were more sensitive to detecting differences in AMD from normal. SWAP defects were greater in depth and area than those in SAP. Central sensitivity (within 1°) changed by −3.9 and −4.9 dB per stage in SAP and SWAP, respectively. Based on defect maps, an AMD Severity Index was derived.ConclusionsGlobal indices of focal loss were more sensitive to detecting early stage AMD from normal. The SWAP sensitivity decline with advancing stage of AMD was greater than in SAP. A new AMD Severity Index quantifies visual field defects on a continuous scale. Although not all patients are suitable for SWAP examinations, it is of value as a tool in research studies of visual loss in AMD.

Integrating Event- and Trend-Based Analyses to Improve Detection of Glaucomatous Visual Field Progression

To present and evaluate a new method of integrating event- and trend-based analyses of visual field progression in glaucoma. Observational cohort study. The study included 711 eyes of 357 glaucoma patients or suspects followed up for an average of 5.0 ± 2.0 years with an average of 7.7 ± 2.3 standard automated perimetry visual fields. An additional group of 55 eyes of 55 glaucoma patients underwent repeated tests over a short period to test the specificity of the method. Event-based analysis of progression was performed using the Guided Progression Analysis (GPA; Carl-Zeiss Meditec, Inc., Dublin, CA). Trend-based assessment used the visual field index (VFI). A hierarchical Bayesian model was built to incorporate results from the GPA in the prior distribution for the VFI slopes, allowing the event-based method to influence the inferences made for the trend-based assessment. The Bayesian method was compared with the conventional ordinary least squares (OLS) regression method of trend-based assessment. Of the 711 eyes followed up over time, 64 (9%) had confirmed progression with GPA. Bayesian slopes of VFI change were able to detect 63 of these eyes (98%). An additional group of 49 eyes (7%) had progression by Bayesian slopes, but not by GPA. Slopes of VFI change calculated by the OLS method were able to identify only 32 of the 64 eyes (50%) with GPA progression. The agreement with GPA was significantly better for the Bayesian compared with the OLS method (κ = 0.68 vs. 0.43, respectively; P<0.001). Eyes progressing only by the Bayesian method had faster rates of change than those progressing only by the OLS method. When applied to the 50 eyes in the stable glaucoma group, both the Bayesian and the OLS methods had a specificity of 96%. A Bayesian hierarchical modeling approach for integrating event- and trend-based assessments of visual field progression performed better than either method used alone. Estimates of rates of change obtained from the Bayesian model had increased precision and may be superior to the conventional OLS method for providing information on the risk of development of functional impairment in the disease.

Comparing rates of retinal nerve fibre layer loss with GDxECC using different methods of visual-field progression

BackgroundThis prospective analysis was designed to examine the rate of RNFL loss using scanning laser polarimetry (GDx enhanced corneal compensation (GDxECC)) in progressing versus non-progressing eyes using various methods to...

The Relationship between Intraocular Pressure Reduction and Rates of Progressive Visual Field Loss in Eyes with Optic Disc Hemorrhage

To evaluate rates of visual field progression in eyes with optic disc hemorrhages and the effect of intraocular pressure (IOP) reduction on these rates. Observational cohort study. The study included 510 eyes of 348 patients with glaucoma who were recruited from the Diagnostic Innovations in Glaucoma Study (DIGS) and followed for an average of 8.2 years. Eyes were followed annually with clinical examination, standard automated perimetry visual fields, and optic disc stereophotographs. The presence of optic disc hemorrhages was determined on the basis of masked evaluation of optic disc stereophotographs. Evaluation of rates of visual field change during follow-up was performed using the visual field index (VFI). The evaluation of the effect of optic disc hemorrhages on rates of visual field progression was performed using random coefficient models. Estimates of rates of change for individual eyes were obtained by best linear unbiased prediction (BLUP). During follow-up, 97 (19%) of the eyes had at least 1 episode of disc hemorrhage. The overall rate of VFI change in eyes with hemorrhages was significantly faster than in eyes without hemorrhages (-0.88%/year vs. -0.38%/year, respectively, P<0.001). The difference in rates of visual field loss pre- and post-hemorrhage was significantly related to the reduction of IOP in the post-hemorrhage period compared with the pre-hemorrhage period (r = -0.61; P<0.001). Each 1 mmHg of IOP reduction was associated with a difference of 0.31%/year in the rate of VFI change. There was a beneficial effect of treatment in slowing rates of progressive visual field loss in eyes with optic disc hemorrhage. Further research should elucidate the reasons why some patients with hemorrhages respond well to IOP reduction and others seem to continue to progress despite a significant reduction in IOP levels. Proprietary or commercial disclosure may be found after the references.

Correlation between macular and retinal nerve fibre layer Fourier-domain OCT measurements and visual field loss in chiasmal compression

The aim of this study was to test the correlation between Fourier-domain (FD) optical coherence tomography (OCT) macular and retinal nerve fibre layer (RNFL) thickness and visual field (VF) loss on standard automated perimetry (SAP) in chiasmal compression. A total of 35 eyes with permanent temporal VF defects and 35 controls underwent SAP and FD-OCT (3D OCT-1000; Topcon Corp.) examinations. Macular thickness measurements were averaged for the central area and for each quadrant and half of that area, whereas RNFL thickness was determined for six sectors around the optic disc. VF loss was estimated in six sectors of the VF and in the central 16 test points in the VF. The correlation between VF loss and OCT measurements was tested with Spearman's correlation coefficients and with linear regression analysis. Macular and RNFL thickness parameters correlated strongly with SAP VF loss. Correlations were generally stronger between VF loss and quadrantic or hemianopic macular thickness than with sectoral RNFL thickness. For the macular parameters, we observed the strongest correlation between macular thickness in the inferonasal quadrant and VF loss in the superior temporal central quadrant (rho=0.78; P<0.001) whereas for the RNFL parameters the strongest correlation was observed between the superonasal optic disc sector and the central temporal VF defect (rho=0.60; P<0.001). Although FD-OCT RNFL and macular thickness measurements were both correlated with VF loss, the correlation was stronger with quadrantic macular than with RNFL thickness measurements in patients with temporal hemianopia. Such measurements could potentially be used to quantify neuronal loss in patients with chiasmal compression.

Analyse d’un nouvel indice d’évaluation du champ visuel, le VFI, dans l’hypertonie oculaire et le glaucome

The Visual Field Index -VFI- is a new perimetric index allowing evaluation of visual function level and progression. In this study, we analysed this new index, that provides a trend analysis of visual field loss progression in Ocular Hypertension and Glaucoma. We also compared results with event analysis. Retrospective study on 94 eyes of 54 patients: 35 OHT(ocular hypertension), 34 early POAG (primary open angle glaucoma) (0>MD>-6 dB), 13 moderate POAG (-6>MD>-12 dB) and 12 advanced POAG (MD<-12 dB), with a mean follow-up of 6.5 years (4 to 8 years). Each subject performed a mean number of 10 standard automated perimetry visual field tests (Humphrey SITA Standard 24-2), excluding tests without reliable indices. VFI progression rate was analysed. VFI progression during the first half period of follow up was compared with that during the second half period. VFI progression was confronted with script alert messages delivered by the last GPA (Guided Progression Analysis) event analysis program. VFI values were "stable or with low progression" in 100% of OHT patients, 88% of early POAG, 38.5% of moderate POAG, 33% of advanced POAG. Progression during the first half period (mean of 3 years) of follow-up could be extrapolated for the second half period in 97% of OHT patients, 76% of early POAG, 70% of moderate POAG, 75% of advanced POAG. Results from VFI trend analysis and GPA event analysis corresponded in 97% of OHT patients, 85% of early POAG, 85% of moderate POAG, and 87% of advanced POAG. VFI seems to be a useful indicator for glaucoma evaluation and progression follow-up. It completes the event analysis. Some very advanced POAG cannot be analysed by GPA event analysis. VFI should be able to be used for further follow-up. All these results require validation in larger population. The purpose would be to assess if VFI is able to detect different profiles of progression to help treatment decisions.

Prediction of Functional Loss in Glaucoma From Progressive Optic Disc Damage

To evaluate the ability of progressive optic disc damage detected by assessment of longitudinal stereophotographs to predict future development of functional loss in those with suspected glaucoma. The study included 639 eyes of 407 patients with suspected glaucoma followed up for an average of 8.0 years with annual standard automated perimetry visual field and optic disc stereophotographs. All patients had normal and reliable standard automated perimetry results at baseline. Conversion to glaucoma was defined as development of 3 consecutive abnormal visual fields during follow-up. Presence of progressive optic disc damage was evaluated by grading longitudinally acquired simultaneous stereophotographs. Other predictive factors included age, intraocular pressure, central corneal thickness, pattern standard deviation, and baseline stereophotograph grading. Hazard ratios for predicting visual field loss were obtained by extended Cox models, with optic disc progression as a time-dependent covariate. Predictive accuracy was evaluated using a modified R(2) index. Progressive optic disc damage had a hazard ratio of 25.8 (95% confidence interval, 16.0-41.7) and was the most important risk factor for development of visual field loss with an R(2) of 79%. The R(2)s for other predictive factors ranged from 6% to 26%. Presence of progressive optic disc damage on stereophotographs was a highly predictive factor for future development of functional loss in glaucoma. These findings suggest the importance of careful monitoring of the optic disc appearance and a potential role for longitudinal assessment of the optic disc as an end point in clinical trials and as a reference for evaluation of diagnostic tests in glaucoma.

A comparison between microperimetry and standard achromatic perimetry of the central visual field in eyes with glaucomatous paracentral visual-field defects

Background and aims:The aim was to correlate retinal sensitivity as determined by scanning laser ophthalmoscope microperimetry (SLO-MP) in glaucomatous eyes with paracentral visual field (VF) defects detected by standard automated...

Comparison of Retinal Nerve Fiber Layer and Optic Disc Imaging for Diagnosing Glaucoma in Patients Suspected of Having the Disease

To compare retinal nerve fiber layer (RNFL) and optic disc topographic imaging for detection of optic nerve damage in patients suspected of having glaucoma. Observational cohort study. A cohort of 82 patients suspected of having glaucoma based on the appearance of the optic nerve. All patients were imaged using the GDx VCC scanning laser polarimeter and HRT (software version 3.0) confocal scanning laser ophthalmoscope. All patients had normal standard automated perimetry visual fields at the time of imaging and were classified based on history of documented stereophotographic evidence of progressive glaucomatous change in the appearance of the optic nerve occurring before the imaging sessions. Areas under the receiver operating characteristic (ROC) curves were used to evaluate the diagnostic accuracies of GDx VCC and the HRT. Forty eyes with progressive glaucomatous optic nerve change were included in the glaucoma group, and 42 eyes without any evidence of progressive damage to the optic nerve followed untreated for an average time of 8.97+/-3.08 years were included in the normal group. The area under the ROC curve for the best parameter from GDx VCC (nerve fiber indicator [NFI]) was significantly larger than that of the best parameter from the HRT (rim volume) (0.83 vs. 0.70; P = 0.044). The NFI parameter also had a larger ROC curve area than that of the contour line-independent parameter glaucoma probability score (0.83 vs. 0.68; P = 0.023). Assuming borderline results as normal, the Moorfields regression analysis classification had a sensitivity of 48% for specificity of 69%. For a similar specificity (70%), the parameter NFI had a significantly larger sensitivity (83%) (P = 0.003). Retinal nerve fiber layer imaging with GDx VCC had a superior performance versus topographic optic disc assessment with the HRT for detecting early damage in patients suspected of having glaucoma. For glaucoma diagnosis, these results suggest that GDx VCC may offer advantage over the HRT when these tests are combined with clinical examination of the optic nerve.

Structure-Function Relationship Is Stronger with Enhanced Corneal Compensation than with Variable Corneal Compensation in Scanning Laser Polarimetry

To compare the structure-function relationship between peripapillary retinal nerve fiber layer (RNFL) retardation, measured with scanning laser polarimetry (SLP) with both enhanced and variable corneal compensation (ECC [enhanced corneal compensation] and VCC [variable corneal compensation], respectively; features of the GDx Nerve Fiber Analyzer; Carl Zeiss Meditec, Inc., Dublin, CA), and visual field (VF) sensitivity, measured with standard automated perimetry (SAP) in normal and glaucomatous eyes and the effect of marked atypical birefringence patterns (ABPs) on this relationship. Thirty-three healthy subjects, and 68 patients with primary open-angle glaucoma (POAG) took part in the study. ECC and VCC images were taken in one randomly selected eye of each subject. VF tests were also obtained in the same eyes. The structure-function relationship was assessed in six peripapillary sectors and their matching VF areas and was reassessed after eliminating eyes with marked ABPs. Correlations (Spearman's correlation coefficients, r(s)) in the structure-function relationship were generally stronger in images taken with ECC than in those taken with VCC. With ECC, the relationship was significantly more curvilinear when VF sensitivity was expressed in the standard decibel scale and more linear when VF sensitivity was expressed in an antilog scale than with VCC. When eyes with marked ABP images were removed from the analysis, the structure-function relationship with VCC improved, and no statistically significantly differences were found in the relationships between VCC and ECC. The structure-function relationship between RNFL retardation and SAP VF sensitivity was stronger in images obtained with the GDx ECC than with the GDx VCC (Carl Zeiss Meditec, Inc., Dublin, CA). ABPs, which appeared more markedly with VCC than with ECC, weakened the structure-function relationship.

Comparing Multifocal VEP and Standard Automated Perimetry in High-Risk Ocular Hypertension and Early Glaucoma

To compare the diagnostic performance of multifocal visual evoked potential (mfVEP) and standard automated perimetry (SAP), in eyes with high-risk ocular hypertension or early glaucoma. Both eyes of 185 individuals with high-risk ocular hypertension or early glaucoma were evaluated. Subjects ranged in age from 37 to 87 (mean +/- SD: 61 +/- 11 years). Pattern-reversal mfVEPs were obtained by using VERIS (Electro-Diagnostic Imaging, San Mateo, CA) with a four-electrode array and were analyzed with custom software. SAP visual fields (SITA-standard; Carl Zeiss Meditec, Inc., Dublin, CA) were obtained within 22.3 +/- 27.0 days of the mfVEP. Stereo disc photographs and Heidelberg Retina Tomograph (HRT) images were obtained during one visit, which was within 24.8 +/- 50.4 days of the mfVEP and 33.1 +/- 62.9 days of the SAP visual field. Abnormalities on the mfVEP were defined by using a variety of cluster criteria: SAP with pattern standard deviation (PSD) P </= 0.05 or glaucoma hemifield test (GHT) outside normal limits, according to OHTS criteria (SAP-OHTS). In separate analyses cluster criteria were used to determine SAP abnormalities. Disc photographs were graded as either glaucomatous optic neuropathy (GON) or normal by two independent masked experts, and disagreements were adjudicated by a third masked expert. The overall Moorfields regression analysis (MRA) result from the HRT was used as a separate diagnostic classification. All eyes classified as "borderline" by the MRA were assigned to the normal category (i.e., "within normal limits"). Sensitivity for mfVEP or SAP was defined as the percentage of GON eyes that had an abnormality on the functional test. Specificity for mfVEP or SAP was defined as the percentage of eyes with normal optic disc structure that had normal functional test results. Disc photographs from 50% of eyes were graded GON. Both eyes were graded GON in 71 (38%) of the 185 subjects. Exactly half as many eyes were abnormal by HRT MRA. The average SAP mean deviation (MD) was +0.3 +/- 2.1 dB; average PSD was 2.3 +/- 1.9 dB. By OHTS criteria, 83 (22%) of the 370 eyes had an abnormal SAP. Depending on the cluster criterion used, the proportion of eyes with an abnormal SAP ranged from 8% to 26% and with an abnormal mfVEP, from 14% to 45%. A criterion with an estimated specificity in normal subjects of 91% resulted in 102 (28%) eyes with an abnormal mfVEP. For criteria with estimated specificities of 95% and 99%, respectively, 88 (24%) eyes and 52 (14%) eyes had an abnormal mfVEP. Agreement between SAP and mfVEP ranged from 75% to 81%. The sensitivity of SAP-OHTS to detect GON (using the disc photograph as diagnostic standard) was 29%, whereas specificity was 84%. Sensitivity of the mfVEP to detect GON, for cluster criteria with disc structure specificity between 84% and 87%, ranged from 28% to 32%. When the HRT MRA was used as the diagnostic standard, sensitivities of both functional tests to detect GON increased to 42%. The diagnostic performance of mfVEP was similar to that of SAP. However, the two modalities agreed in only approximately 80% of eyes, suggesting that they may detect slightly different functional deficits.