Number Of Visual Field Research Articles

The number of examinations required for the accurate prediction of the progression of the central 10-degree visual field test in glaucoma

The purpose of the study was to investigate the number of examinations required to precisely predict the future central 10-degree visual field (VF) test and to evaluate the effect of fitting non-linear models, including quadratic regression, exponential regression, logistic regression, and M-estimator robust regression model, for eyes with glaucoma. 180 eyes from 133 open angle glaucoma patients with a minimum of 13 Humphrey Field Analyzer 10-2 SITA standard VF tests were analyzed in this study. Using trend analysis with ordinary least squares linear regression (OLSLR), the first, second, and third future VFs were predicted in a point-wise (PW) manner using a varied number of prior VF sequences, and mean absolute errors (MAE) were calculated. The number of VFs needed to reach the minimum 95% confidence interval (CI) of the MAE of the OLSLR was investigated. We also examined the effect of applying other non-linear models. When predicting the first, second, and third future VFs using OLSLR, the minimum MAE was obtained using VF1–12 (2.15 ± 0.98 dB), VF1–11 (2.33 ± 1.10 dB), and VF1–10 (2.63 ± 1.36 dB), respectively. To reach the 95% CI of these MAEs, 10, 10, and 8 VFs were needed for the first, second and third future VF predictions, respectively. No improvement was observed by applying non-linear regression models. As a conclusion, approximately 8–10 VFs were needed to achieve an accurate prediction of PW VF sensitivity of the 10-degree central VF.

Comparison of Methods to Detect and Measure Glaucomatous Visual Field Progression.

PurposeTo compare methods to assess visual field (VF) progression in glaucoma.Methods4,950 VFs of 253 primary open angle-glaucoma patients were evaluated for progression with the following methods: clinical evaluation, guided progression analysis (GPA), mean deviation (MD), and visual field index (VFI) rates, Advanced Glaucoma Intervention Study (AGIS) and Collaborative Initial Glaucoma Treatment Study (CIGTS) scores, pointwise linear regression (PLR), permutation of PLR (PoPLR), and glaucoma rate index (GRI). A separate simulated series of longitudinal VFs was assessed with all methods except for GPA and clinical evaluation.ResultsThe average (±SD) age of the patients at baseline was 65.4 (±11.5) years. The average (±SD) follow-up was 11.8 (±4.6) years, and the mean (±SD) number of VFs was 16.8 (±7.0). Proportion of series detected as progressing was 65% for PoPLR, 58% for GRI, 41% for GPA, 40% for PLR, 36% for CIGTS, 35% for clinicians, 31% for MD rate, 29% for AGIS, and 22% for VFI rate. Median times to detection of progression were 7.3 years for PoPLR, 7.5 years for GRI, 11 years for clinicians, 14 years for GPA, 16 years for PLR, 17 years for CIGTS, 19 years for AGIS, and more than 20 years for MD and VFI rates. In simulated VF series, GRI had the highest partial area under the receiver operator characteristic curve (0.040) to distinguish between glaucoma progression and aging/cataract decay, followed by VFI rate (0.028), MD rate (0.024), and PoPLR (0.006).ConclusionsGRI and PoPLR showed the highest proportion of series detected as progressing and shortest times to progression detection. GRI exhibited the best ability to detect progression in the simulated VF series.Translational RelevanceKnowledge of the properties of every method would allow tailoring application in both clinical and research settings.

Risk Factors for Fast Visual Field Progression in Glaucoma

To identify baseline and longitudinal risk factors for fast visual field (VF) decay in patients with open-angle glaucoma. Retrospective cohort study. Patients with open-angle glaucoma with ≥6 VFs and ≥4 years of follow-up were included. VF decay rates were measured with the following methods: mean deviation (MD) rate, VF index (VFI) rate, and the Glaucoma Rate Index (GRI). The relationship between VF rates and clinical variables were investigated with linear mixed models. Logistic regression analysis was performed to determine which factors were associated with fast progression. A total of 1317 eyes of 745 patients with a mean (± SD) age of 63.3 (±10.9) years and a median (interquartile range) MD-2.4 (-0.7 to-5.6) dB at baseline were analyzed. The median (interquartile range) number of VFs was 12 (9 to 16), and mean follow-up duration was 11.5 (±3.7) years. Older age (P < .001), higher peak intraocular pressure (IOP) (P < .001), and glaucoma surgery during the study period (P < .001) were associated with faster rates of progression regardless of the method used. Worse baseline MD was associated with MD rate (P= .02), but neither with VFI rate (P=.37) nor GRI (P= .31); whereas pseudoexfoliative glaucoma was associated with faster rates of progression with MD (P = .008) and VFI (P = .01) rates, but not with GRI. Higher peak IOPs (P= .005) was a significant predictor for fast progression. In this cohort, older age, peak IOP, pseudoexfoliative glaucoma, and baseline MD were associated with the rate of glaucomatous VF worsening. Fast progressors had a higher peak IOP than non-fast progressors. The identification and appropriately aggressive treatment of fast progressors would reduce visual disability from glaucoma.

Visual Field Progression in Patients with Primary Angle-Closure Glaucoma Using Pointwise Linear Regression Analysis

To evaluate visual field (VF) progression and rate of glaucomatous VF loss in patients with primary angle-closure glaucoma (PACG) using pointwise linear regression (PLR) trend analysis. Clinic-based retrospective study. Primary angle-closure glaucoma patients with 5 or more reliable VF tests and with 5 years or more of follow-up. Visual field progression was assessed by PROGRESSOR software version 3.7 (Medisoft, Leeds, United Kingdom) and was defined by the presence of at least 2 adjacent testing points located within the same hemifield that showed progression with a change of -1 dB/year or more (P < 0.01) for inner points or -2 dB/year or more (P < 0.01) for edge points. We also performed a logistic regression analysis to determine the variables associated with rapid progression (defined as mean slope of progressing points ≥-1.5 dB/year). Visual field progression and rate of VF loss. Of the 1296 patients who were assessed, 398 (30.7%) fulfilled the inclusion criteria of 5 or more VFs and 5 years or more of follow-up. Visual field progression was observed in 63 of 398 eyes (15.8%) according to the PLR criteria. The overall mean rate of VF change for these patients was -0.12±0.51 dB/year over a mean follow-up period of 10.4±3.7 years. There were no significant differences in the age, gender distribution, follow-up duration, or number of VFs between those who showed progression and those who did not (all P > 0.05). The most common sector of VF progression was the superior arcuate area (65%). Rapid progression was found in 36 patients (57%). Multiple logistic regression analysis revealed older age and higher vertical cup-to-disc ratio (VCDR) at presentation as predictors of rapid progression (all P < 0.005) in the progressing group (n= 63). In patients with PACG being managed in a hospital setting, VF progression was noted in 15.8%, and the overall rate of VF loss was -0.12±0.51 dB/year. The superior arcuate was the most common sector of progression. Older age and higher VCDR at presentation were associated with rapid progression.

Global Visit Effects in Point-Wise Longitudinal Modeling of Glaucomatous Visual Fields.

One of the difficulties in modeling visual field (VF) data is the sometimes large and correlated measurement errors in the point-wise sensitivity estimates. As these errors affect all locations of the same VF, we propose to model them as global visit effects (GVE). We evaluate this model and show the effect it has on progression estimation and prediction. Visual field series (24-2 Full Threshold; 15 biannual VFs per patient) of 125 patients with primary glaucoma were included in the analysis. The contribution of the GVE was evaluated by comparing the fitting and predictive ability of a conventional model, which does not contain GVE, to such a model that incorporates the GVE. Moreover, the GVE's effect on the estimated slopes was evaluated by determining the absolute difference between the slopes of the models. Finally, the magnitude of the GVE was compared with that of other measurement errors. The GVE model showed a significant improvement in both the model fit and predictive ability over the conventional model, especially when the number of VFs in a series is limited. The average absolute difference in slopes between the models was 0.13 dB/y. Lastly, the magnitude of the GVE was more than three times larger than the measureable factors combined. By incorporating the GVE in the longitudinal modeling of VF data, better estimates may be obtained of the rate of progression as well as of predicted future sensitivities.

Parafoveal Scotoma Progression in Glaucoma: Humphrey 10-2 versus 24-2 Visual Field Analysis

To compare the performance of 10-2 versus 24-2 visual fields (VFs) in detecting progression of initial parafoveal scotoma (IPFS) in glaucomatous eyes. Retrospective, observational study. Glaucoma patients with the following criteria: (1) an IPFS (≥ 3 adjacent points with P<0.05 within the central 10° degrees of fixation, 1 point or more with P<0.01 lying at the innermost paracentral points, and no scotoma outside the central 10°) in either hemifield based on 2 reliable Humphrey 24-2 Swedish interactive threshold algorithm standard VFs, and (2) 5 or more 10-2 and 24-2 VFs. Based on threshold map sensitivities, VF progression, defined as having 1 or more significantly progressing point(s) with a slope of sensitivity of less than -1.0 dB/year at P<0.01, was evaluated using pointwise linear regression. The number of progressing eyes in 10-2 and 24-2 VF analyses. Fifty eyes (50 patients) were included (mean age ± standard deviation, 62 ± 9 years). Mean follow-up period (5.7 vs. 5.6 years) and number of VFs (7.6 vs. 7.8) were similar between 10-2 and 24-2 analyses (all P>0.3). Significantly more progressing eyes were detected in 10-2 than in 24-2 analyses (24 vs. 11 eyes; P = 0.007). This difference became greater within the central 10° (24 vs. 4 eyes; P<0.001). Four of the 11 progressing eyes in 24-2 analysis were missed in 10-2 analysis, whereas 17 of the 24 progressing eyes in 10-2 analysis were missed in 24-2 analysis. The 4 progressing eyes missed in 10-2 analysis had progressing point(s) only outside the central 10° in 24-2 analysis. The other 3 eyes with progressing point(s) only outside the central 10° in 24-2 analysis were detected as progressing in 10-2 analysis. Similar results were obtained when more stringent criteria (at least 2 significantly progressing points within the same hemifield) were used for VF progression. The 10-2 VF detects more progressing eyes than the 24-2 VF in glaucoma patients with IPFS, suggesting that closer surveillance of the central VF using testing algorithms with closely spaced grids is warranted in eyes with parafoveal scotomas. Proprietary or commercial disclosure may be found after the references.

Agreement between event-based and trend-based glaucoma progression analyses

To evaluate the agreement between event- and trend-based analyses to determine visual field (VF) progression in glaucoma. VFs of 175 glaucoma eyes with ≥5 VFs were analyzed by proprietary software of VF analyzer to determine progression. Agreement (κ) between trend-based analysis of VF index (VFI) and event-based analysis (glaucoma progression analysis, GPA) was evaluated. For eyes progressing by event- and trend-based methods, time to progression by two methods was calculated. Median number of VFs per eye was 7 and follow-up 7.5 years. GPA classified 101 eyes (57.7%) as stable, 30 eyes (17.1%) as possible and 44 eyes (25.2%) as likely progression. Trend-based analysis classified 122 eyes (69.7%) as stable (slope >-1% per year or any slope magnitude with P>0.05), 53 eyes (30.3%) as progressing with slope <-1% per year, P≤0.05 (sensitive criteria), and 37 eyes (21.1%) as progressing with slope <-1% per year, P≤0.01 (specific criteria). κ between sensitive criteria of GPA (possible combined with likely progression) and trend-based analysis was 0.48, and between specific criteria of GPA (possible clubbed with no progression) and trend-based analysis was 0.50. In eyes progressing by sensitive criteria of both methods (42 eyes), median time to progression by GPA (4.9 years) was similar (P=0.30) to trend-based method (5.0 years). This was also similar in eyes progressing by specific criteria of both methods (25 eyes; 5.6 years versus 5.9 years, P=0.23). Agreement between event- and trend-based progression analysis was moderate. GPA seemed to detect progression earlier than trend-based analysis, but this wasn't statistically significant.

Validation of Point-Wise Exponential Regression to Measure the Decay Rates of Glaucomatous Visual Fields

This study was conducted to validate a recently described technique for measuring the rates of visual field (VF) decay in glaucoma. A pointwise exponential regression (PER) model was used to calculate average rates of faster and slower deteriorating VF components, and that of the entire VF. Rapid progressors had a faster component rate of >25%/year. Mean deviation (MD) and visual field index (VFI) forecasts were calculated by (1) extrapolation of linear regression of MD and VFI, and (2) calculation de novo from the PER-predicted final thresholds. The mean (± SD) years of follow-up and number of VFs were 9.2 (± 2.7) and 13.7 (± 5.8), respectively. The median rates of the decay were -0.1 and 3.6 (%/year) for the slower and the faster components, respectively. The "rapid progressors" (32% of eyes) had a mean decay rate of 52.2%/year. In comparison with actual values, the average absolute difference and the mean squared error for MD forecasts with linear extrapolation of indices were 3.58 dB and 31.91 dB(2), and with the de novo recalculation from PER predictions were 2.95 dB and 17.49 dB(2), respectively. Similar results were obtained for VFI forecasts. Comparisons of the prediction errors for both the MD and VFI favored the PER forecasts (P < 0.001). PER for measuring rates of VF decay is a robust indicator of rates across a wide range of disease severity and can predict future global indices accurately. The identification of "rapid progressors" identifies high-risk patients for appropriate treatment.

Comparison of PROGRESSOR and Glaucoma Progression Analysis 2 to Detect Visual Field Progression in Treated Glaucoma Patients.

We compared the abilities of PROGRESSOR and Glaucoma Progression Analysis 2 (GPA2) to detect glaucomatous visual field (VF) progression. Retrospective cohort. We reviewed the charts of glaucoma patients with repeatable VF loss and ≥ 8 SITA-Standard 24-2 VFs. Progression was evaluated using 3 methods: (1) PROGRESSOR pointwise linear regression (Medisoft, Inc), (2) GPA2 VF index (VFI) regression (GPA-VFI), and (3) GPA Early Manifest Glaucoma Trial (EMGT) criteria (Carl Zeiss Meditec, Inc; GPA-EMGT). For PROGRESSOR, progression was determined when at least 2 adjacent test points in the same hemifield progressed by more than 1.0 dB/y, P < 0.01. For GPA-VFI, progression was defined when VFI rate was more than 1.0%/y, P < 0.01. A total of 130 eyes [130 patients; mean (SD) age, 63.6 (12.7) years; mean (SD) number of VF, 11.2 (3.6); mean follow-up time, 7.3 (1.8) years] were enrolled. There was a significant correlation between VFI and PROGRESSOR rates of change (r = 0.81, P < 0.01). The number of eyes progressing based on PROGRESSOR, GPA-VFI, and the GPA-EMGT criteria was 55, 37, and 46, respectively (P = 0.06). There was a moderate agreement between PROGRESSOR and the GPA-EMGT (κ = 0.43), between PROGRESSOR and GPA-VFI (κ = 0.57), and between GPA-VFI and GPA-EMGT (κ = 0.45). PROGRESSOR and GPA-EMGT tended to detect similar numbers of progressing points per eye [3.7 (5.8) vs 3.1 (4.4), P = 0.50, respectively]. The 3 methods showed statistically similar sensitivities for the detection of VF progression. In addition, the EMGT and PROGRESSOR criteria revealed good spatial consistency.

Risk Factors for Visual Field Progression in Treated Glaucoma

To determine intraocular pressure (IOP)-dependent and IOP-independent variables associated with visual field (VF) progression in treated glaucoma. Retrospective cohort of the Glaucoma Progression Study. Consecutive, treated glaucoma patients with repeatable VF loss who had 8 or more VF examinations of either eye, using the Swedish Interactive Threshold Algorithm (24-2 SITA-Standard, Humphrey Field Analyzer II; Carl Zeiss Meditec, Inc, Dublin, California), during the period between January 1999 and September 2009 were included. Visual field progression was evaluated using automated pointwise linear regression. Evaluated data included age, sex, race, central corneal thickness, baseline VF mean deviation, mean follow-up IOP, peak IOP, IOP fluctuation, a detected disc hemorrhage, and presence of beta-zone parapapillary atrophy. We selected 587 eyes of 587 patients (mean [SD] age, 64.9 [13.0] years). The mean (SD) number of VFs was 11.1 (3.0), spanning a mean (SD) of 6.4 (1.7) years. In the univariable model, older age (odds ratio [OR], 1.19 per decade; P=.01), baseline diagnosis of exfoliation syndrome (OR, 1.79; P=.01), decreased central corneal thickness (OR, 1.38 per 40 μm thinner; P<.01), a detected disc hemorrhage (OR, 2.31; P<.01), presence of beta-zone parapapillary atrophy (OR, 2.17; P<.01), and all IOP parameters (mean follow-up, peak, and fluctuation; P<.01) were associated with increased risk of VF progression. In the multivariable model, peak IOP (OR, 1.13; P<.01), thinner central corneal thickness (OR, 1.45 per 40 μm thinner; P<.01), a detected disc hemorrhage (OR, 2.59; P<.01), and presence of beta-zone parapapillary atrophy (OR, 2.38; P<.01) were associated with VF progression. IOP-dependent and IOP-independent risk factors affect disease progression in treated glaucoma. Peak IOP is a better predictor of progression than is IOP mean or fluctuation.

Glaucoma With Early Visual Field Loss Affecting Both Hemifields and the Risk of Disease Progression

To evaluate whether damage to both hemifields in glaucomatous eyes predicts more rapid disease progression than does single-hemifield involvement. We reviewed the medical records of 43 660 consecutive patients. Eyes with glaucomatous optic neuropathy, 10 or more Swedish Interactive Threshold Algorithm standard 24-2 visual fields in at least 5 years, and mean deviation (MD) smaller than -6.0 dB were included. Pointwise linear regression was used to determine progression. Cox proportional hazards analysis was used to calculate risk of progression based on different baseline covariates. We enrolled 205 eyes (205 patients; mean [SD] age, 64.2 [11.0] years; follow-up, 6.5 [1.8] years; number of visual fields, 12.3 [2.9]). Patients were divided into 3 groups: initial superior defect (group A; n = 79; MD, -3.4 [1.9] dB), initial inferior defect (group B; n = 61; MD, -3.4 [1.8] dB), and both hemifields affected (group C; n = 65; MD, -4.2 [1.5] dB). Group C progressed faster than did groups A and B (P < .02). Multivariate analysis showed significant effect of higher baseline intraocular pressure, thinner central corneal thickness, and initial damage to both hemifields. Initial damage to both hemifields increases the risk of glaucoma progression. More aggressive therapy should be considered for these eyes.

Increased rate of visual field loss associated with larger initial visual field threshold values on follow-up of open-angle glaucoma.

To determine the changes in the visual field over time and the factors that contribute to these changes on follow-up of open-angle glaucoma patients. From a retrospective review of patients' charts and visual fields, 30 eyes from 30 patients with open-angle glaucoma with a minimum of 3 years of follow-up were chosen. Visual fields were obtained with the Octopus perimeter about every 4 months. Regression analysis was used to obtain the slope for all the threshold values for each eye for the total field and nine different regions over time. Optic disc area was measured from single fundus photographs obtained at the beginning of the period of observation. The open-angle glaucomas were observed for a mean of 6.7 +/- 2.3 years. The number of visual fields per eye was 20.7 +/- 8.0. The mean threshold value of the total field for the first three visual fields was 18.0 +/- 5.2 dB. The visual fields of the 30 eyes with a mean intraocular pressure of 18 +/- 2 mm Hg during follow-up showed a significant decrease in their visual field slope of -0.384 dB/y for the total visual field. On multivariate analysis, the slope or rate of visual field loss was significantly correlated with the average of the first three initial visual field thresholds for the total visual field, temporal, and central regions so that the greater the threshold value the more rapid the rate of the visual field loss. For the total visual field and for the nasal, superior nasal, and temporal regions with lower initial threshold values, the rate of visual field loss was curvilinear with the rate of visual field loss increasing at greater initial mean threshold values. The other regions of the visual field showed a linear increasing rate of visual field loss with larger initial threshold values. Other factors significantly associated with progression of visual field loss were refractive error, race, the slope of the pulse rate, and the mean percent false positives and false negatives for initial to final observations. The mean and the slope of intraocular pressure from initial to final observation were not significant variables. In open-angle glaucomas observed for 6.7 +/- 2.3 years, there was a more rapid rate of visual field loss associated with larger initial threshold values and a less rapid rate of visual field loss associated with smaller initial threshold values indicating that the progression of visual field loss is greater in an earlier stage of disease.

A new diffuse loss index for estimating general glaucomatous visual field depression

Experience with a number of visual fields has shown that the algorithm used earlier for estimating general depression in glaucomatous visual fields was too conservative. A new, more sophisticated algorithm for calculating diffuse loss has been devised and the results obtained in the evaluation of 20 glaucomatous visual fields were compared with those obtained manually. The new algorithm is less restrictive, yet produces values for diffuse loss which agree well with the empirical estimates (R = 0.97, N = 14). The new diffuse loss index is also compared with the mean defect index (R = 0.77, N = 159), the 18th Bebie curve ranked value (R = 0.87, N = 159), and the previous diffuse loss index (R = 0.98, N = 105). A general discussion of various aspects of diffuse loss is included.

A microscopical method for the determination of potato-starch in flour

A microscopical method is described for estimating the percentage of potato-starch added to flour. A haemocytometer (as used for determining the number of blood corpuscles in blood samples) is filled with a rather stiff suspension of flour, in which the starch grains are uniformly distributed. The suspension in the haemocytometer is then liquified by warming so that all the starch grains collect on the bottom. The potato-starch grains are readily identified microscopically. By combination of counting and classifying the grains according to size, the amount of potato-starch in a certain number of visual fields may be estimated. Some data are given concerning the potato-starch content of Dutch bread flour during the period September 11th-October 30th, 1950.