Biomedical subjects

Douglas Hoffman

Publications and source records attributed to Douglas Hoffman.

8 recordsLinked to original sources

PubMed2006

Frequency-doubling perimetry: comparison with standard automated perimetry to detect glaucoma.

PURPOSE: To compare second generation frequency-doubling perimetry (FDP) with standard automated perimetry (SAP) to detect glaucomatous visual field abnormalities. DESIGN: Prospective, cross-sectional, controlled observational study. METHODS: Fifty eyes of 50 patients with glaucoma with confirmed SAP visual field abnormalities and 42 eyes from 42 normal control subjects were studied. Swedish Interactive Thresholding Algorithm (SITA) standard 24-2 SAP and FDP visual fields were performed. The correlation of global indices and the number of defects on total deviation (TD) and pattern deviation (PD) plots were compared. The spatial concordance of FDP and SAP defect locations was determined. RESULTS: In patients with glaucoma, significant correlations of mean deviation (MD) and pattern standard deviation (PSD) were found between SAP and FDP (P < .001 for MD and P < .001 for PSD), but not in the normal group. FDP had significantly greater defect scores than SAP on total deviation and PD plots in the glaucoma group (P = .028 and P = .01, respectively). In comparison with SAP, sensitivity and specificity of FDP were 92% and 98% with glaucoma hemifield test criteria and 98% and 93% with PSD <5% criteria, respectively. Similarly high diagnostic precision was found with MD and PSD (at 95% specificity; MD and PSD sensitivity was 82% and 90%, respectively). The location of defects within 12 hemifield clusters found with FDP agreed moderately well with those detected with SAP (kappa = .48). CONCLUSIONS: FDP and SAP perform similarly in their ability to detect visual field defects in early to moderate glaucoma. Larger and deeper defects detected with FDP suggests the possibility of earlier detection at high specificity.

Adult↗

PubMed2005

Pointwise linear regression for evaluation of visual field outcomes and comparison with the advanced glaucoma intervention study methods.

OBJECTIVE: To investigate pointwise linear regression (PLR) for longitudinal evaluation of visual fields and to compare results with those of the Advanced Glaucoma Intervention Study (AGIS) criteria. METHODS: We selected 509 eyes (401 patients) from the AGIS with 3 or more years of follow-up, 7 or more visual field examinations, and an AGIS reference score of 16 or lower. Visual field change at test locations was defined as a change of threshold sensitivity of 1 dB/y or higher and P<or=.01. Several sets of criteria were investigated for defining change of visual field series with PLR. MAIN OUTCOME MEASURES: Progression or improvement of visual field series with PLR and AGIS criteria. RESULTS: Mean (SD) follow-up time and baseline AGIS score were 7.4 (1.7) years and 7.7 (4.4), respectively. Pairwise agreement between AGIS and various PLR criteria ranged from 52% to 64% with the kappa statistic varying between 0.22 (95% confidence interval, 0.15-0.29) and 0.30 (95% confidence interval, 0.22-0.38). One hundred thirty-eight (27%) and 151 (30%) eyes progressed (85 eyes or 17% detected by both methods) while 72 (14%) and 11 (2%) eyes improved (5 eyes or 1% detected by both methods) based on AGIS and the most rigorous PLR criteria, respectively. CONCLUSIONS: Based on rigorous, clinically relevant criteria, PLR detects progression in a similar proportion of eyes compared with AGIS criteria. Pointwise linear regression may be superior to AGIS methods since it identifies fewer visual field series as improving.

Adult↗

PubMed2004

Identifying early glaucoma with optical coherence tomography.

PURPOSE: To evaluate performance of optical coherence tomography (OCT) for detection of early glaucoma. DESIGN: Observational case-control study. METHODS SETTING: University-based tertiary care center. STUDY POPULATION: One eye from 50 normals, 42 glaucoma suspects, and 59 early glaucoma patients meeting the following criteria: visual field (VF) mean deviation > or =-6.00 dB, age > or =40 years, spherical refractive error < or =5 diopters, astigmatism < or =3 diopters, and visual acuity > or =20/30. OBSERVATION PROCEDURE: Early glaucoma by VF (EGVF) was described as repeatable abnormal achromatic VFs based on predefined criteria. Glaucoma suspects (GS) were defined as presence of glaucomatous disk appearance with normal achromatic VFs. OUTCOME MEASURES: Average nerve fiber layer thickness (NFLT) and NFLT in each of four quadrants and 12 clock-hour sectors. Receiver operating characteristic curves and sensitivity and specificity were used to assess the performance of OCT. RESULTS: Average NFLT was 128.4 +/- 15.4, 102.0 +/- 25.4, and 86.5 +/- 31.5 microm in normal, GS, and EGVF eyes, respectively. Normal eyes were different from both glaucoma groups (P <.001); NFLT in the superior quadrant and at the 11 o'clock position had the highest area under the receiver operating characteristic curve (.840 and.933) in the GS and EGVF groups (P =.03). The sensitivity of the OCT for detection of glaucoma was 71% and 85% for the GS and EGVF groups with specificity fixed at 90%. CONCLUSION: The OCT discriminates well between eyes with early perimetric glaucoma and normal eyes. However, its performance is less adequate in eyes with suspicious disk and normal VFs.

Adult↗

PubMed2004

Optic disk appearance in advanced age-related macular degeneration.

PURPOSE: To describe and quantify the appearance of the optic disk in patients with advanced age-related macular degeneration (ARMD). DESIGN: Retrospective comparative study. METHODS: A total of 316 charts were reviewed. From these, 45 subjects with advanced ARMD (defined as geographic atrophy or disciform scar) in at least one eye were enrolled. Patients with glaucoma or glaucoma visual field defects were excluded. The probability of glaucomatous optic nerve damage was scored by evaluation of stereoscopic optic disk photographs in a masked fashion, according to a predefined evaluation scale and measured with confocal ophthalmoscopy (Heidelberg Retinal Tomograph; HRT). The area of macular involvement was measured in units of disk area. The optic disk evaluation scores and HRT measurements of a group of eyes with a large area of ARMD were compared with their fellow eyes with smaller areas of ARMD. The correlations between the area of macular involvement with the optic disk evaluation scores and HRT measurements were analyzed. MAIN OUTCOME MEASURES: The optic disk evaluation scores and the HRT measurements between study groups. RESULTS: Eyes with larger areas of ARMD had optic disks that were more likely to be classified as glaucomatous by clinical evaluation (3.45 +/- 0.23 vs 3.05 +/- 0.18, P =.015) and by HRT imaging analysis (-0.995 +/- 0.423 vs -0.376 +/- 0.249, P =.030) than the fellow eyes with smaller areas of ARMD. For eyes with six or more disk areas of ARMD, larger areas of ARMD correlated with a higher cup/disk ratio (P =.022), smaller neuroretinal rim area (P =.022), and glaucomatous classification (P =.040) with HRT discriminant function analysis. CONCLUSIONS: Eyes with large areas of geographic or diskiform ARMD have optic disk structural alterations that resemble glaucomatous optic neuropathy. This should be taken into consideration when evaluating patients with ARMD for glaucomatous damage.

Aged↗

PubMed2004

Variable corneal compensation improves discrimination between normal and glaucomatous eyes with the scanning laser polarimeter.

PURPOSE: The presently available scanning laser polarimeter (SLP) has a fixed corneal compensator (FCC) that neutralizes corneal birefringence only in eyes with birefringence that matches the population mode. A prototype variable corneal compensator (VCC) provides neutralization of individual corneal birefringence based on individual macular retardation patterns. The aim of this study was to evaluate the relative ability of the SLP with the FCC and with the VCC to discriminate between normal and glaucomatous eyes. DESIGN: Prospective, nonrandomized, comparative case series. PARTICIPANTS: Algorithm-generating set consisting of 56 normal eyes and 55 glaucomatous eyes and an independent data set consisting of 83 normal eyes and 56 glaucomatous eyes. TESTING: Sixteen retardation measurements were obtained with the SLP with the FCC and the VCC from all subjects. MAIN OUTCOME MEASURES: Dependency of parameters on age, gender, ethnic origin, and eye side was sought. Logistic regression was used to evaluate how well the various parameters could detect glaucoma. Discriminant functions were generated, and the area under the receiver operating characteristic (ROC) curve was determined. RESULTS: Discrimination between normal and glaucomatous eyes on the basis of single parameters was significantly better with the VCC than with the FCC for 6 retardation parameters: nasal average (P = 0.0003), superior maximum (P = 0.0003), ellipse average (P = 0.002), average thickness (P = 0.003), superior average (P = 0.010), and inferior average (P = 0.010). Discriminant analysis identified the optimal combination of parameters for the FCC and for the VCC. When the discriminant functions were applied to the independent data set, areas under the ROC curve were 0.84 for the FCC and 0.90 for the VCC (P<0.021). When the discriminant functions were applied to a subset of patients with early visual field loss, areas under the ROC curve were 0.82 for the FCC and 0.90 for the VCC (P<0.016). CONCLUSION: Individual correction for corneal birefringence with the VCC significantly improved the ability of the SLP to distinguish between normal and glaucomatous eyes and enabled detection of patients with early glaucoma.

Adult↗

PubMed2004

Predictive factors for glaucomatous visual field progression in the Advanced Glaucoma Intervention Study.

PURPOSE: To investigate the risk factors associated with visual field (VF) progression in the Advanced Glaucoma Intervention Study (AGIS) with pointwise linear regression (PLR) analysis of serial VFs. DESIGN: Prospective, multicenter, randomized clinical trial. PARTICIPANTS: Five hundred nine eyes of 401 patients from the AGIS with a baseline VF score of or=7 VF examinations, and >or=3 years of follow-up were selected. MAIN OUTCOME MEASURE: Visual field progression. METHODS: This is a cohort study of patients enrolled in a prospective randomized clinical trial (AGIS). Worsening of a test location on PLR analysis was defined as a change of threshold sensitivity of >or=1.00 decibels a year, with P<or=0.01. Visual field progression was defined as worsening of at least 2 test locations within a Glaucoma Hemifield Test cluster with PLR analysis. Multivariate logistic regression was used to determine risk factors associated with VF worsening. Intraocular pressure (IOP) fluctuation was defined as standard deviation of the IOP at all visits after the initial surgery. RESULTS: The mean (+/- standard deviation) follow-up time and baseline AGIS score were 7.4 (+/-1.7) years and 7.7 (+/-4.4), respectively. Visual field progression was detected with PLR analysis in 151 eyes (30%). Older age at the initial intervention (P = 0.0012; odds ratio [OR], 1.30; 95% confidence interval [CI], 1.11-1.50), larger IOP fluctuation (P = 0.0013; OR, 1.31; 95% CI, 1.12-1.54), increasing number of glaucoma interventions (P = 0.01; OR, 1.74; 95% CI, 1.14-2.64), and longer follow-up (P = 0.02; OR, 1.19; 95% CI, 1.03-1.38) were associated with increased odds of VF progression. When regression analyses were repeated in eyes with and without a history of cataract extraction, IOP fluctuation was the only variable to be consistently associated with VF progression. CONCLUSION: Both increasing age and greater IOP fluctuation increase the odds of VF progression by 30% (for each 5-year increment in age and 1-mmHg increase in IOP fluctuation). The higher risk conferred by IOP fluctuation was consistently observed in eyes with and without a history of cataract extraction.

Adult↗

PubMed2004

Prediction of visual field progression in glaucoma.

PURPOSE: To determine the probability of future glaucomatous visual field (VF) progression with clinical and perimetric data. METHODS: One hundred sixty-one eyes of patients (161) enrolled in the Advanced Glaucoma Intervention Study (AGIS) with >or=8 years of follow-up and a baseline VF score <or=16 were selected. VF progression at 8 years was determined with point-wise linear regression (PLR) analysis, using a two-omitting algorithm. The course of VF series over the first 4 years of follow-up was quantified by an index, the sum of slopes, which is the sum of all slopes of VF thresholds with P < 0.05 when PLR was performed on the 4-year data. The following parameters were included in a logistic regression model to predict 8-year outcomes from the first 4 years of follow-up: intervention sequence, age, AGIS VF score, mean IOP, IOP fluctuation, and sum of slopes. RESULTS: Sixty-four (40%) eyes progressed after 8 years as determined by PLR analysis. Two parameters were predictive of subsequent VF progression, as identified at 8 years (predictive power: 76%): more negative sum of slopes (i.e., faster or more extensive deterioration; P < 0.001) and older age at 4 years (P = 0.049). When sum of slopes alone was used to predict outcomes at 8 years, the predictive power was the same. CONCLUSIONS: The VF sum of slopes can be used to estimate the probability of subsequent VF worsening with reasonable, clinically useful accuracy. This probability may be combined with other clinical information for more effective clinical predictions and treatment decisions.

Aged↗

PubMed2003

Neural networks to identify glaucomatous visual field progression.

PURPOSE: To describe a method to determine progression of glaucoma based on visual field thresholds. DESIGN: Observational retrospective longitudinal cohort study. METHODS: A back propagation neural network with three hidden layers was developed with commercial software. Visual field data from 80 patients who participated in the Advanced Glaucoma Intervention Study (AGIS) were used. Glaucomatous visual field progression was defined as a change of 4 or more units in the AGIS score, confirmed by at least two sequential subsequent tests. Inputs to the neural network consisted of threshold measurements from 55 visual field locations from the baseline examination and each follow-up examination. The data set was randomized so the sequence of examinations would not influence the training or testing of the neural network. Two thirds of the randomized data were used for training and the remaining one third for testing. RESULTS: The mean age of 80 patients enrolled in AGIS at initial examination was 67.4 (+/- 7.3 standard deviation [SD]) years. The average follow-up period was 7.2 (+/-2.3 SD) years and the mean duration between examinations was 0.46 (+/- 0.39 SD) years. The neural network estimated the probability of progression for each baseline and follow-up comparison with an average sensitivity of 86% and specificity of 88%. The area under the receiver operating characteristic (ROC) curve was 0.92, with a sensitivity of 86% at the 80% specificity level and a sensitivity of 91% at the 90% specificity level. CONCLUSIONS: From analysis of AGIS data, progression of glaucoma could be detected from visual field thresholds with a neural network.

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