Biomedical subjects

Linda M Zangwill

Publications and source records attributed to Linda M Zangwill.

At least 19 recordsLinked to original sources

PubMed2007

The effects of study design and spectrum bias on the evaluation of diagnostic accuracy of confocal scanning laser ophthalmoscopy in glaucoma.

PURPOSE: To assess the effects of study design and spectrum bias on the evaluation of diagnostic accuracy of confocal scanning laser ophthalmoscopy (CSLO) in glaucoma. METHODS: Analysis 1 included 67 eyes with glaucomatous visual field loss and 56 eyes of normal volunteers. Estimates of diagnostic accuracy in this analysis were compared to those obtained from analysis 2, which included a cohort of patients with suspected glaucoma, but without visual field loss at the time of CSLO imaging. For analysis 2, 40 eyes with progressive glaucomatous optic disc change were included in the glaucoma group and 43 eyes without any evidence of progressive damage to the optic nerve that were observed untreated for an average time of 9.01 +/- 3.09 years were included in the normal group. Areas under the receiver operating characteristic (ROC) curves (AUC) were used to evaluate diagnostic accuracy of CSLO parameters. RESULTS: There was a statistically significant difference between the performance of the parameter with largest AUC, discriminant function Bathija, in analysis 1 (AUC = 0.91) compared with its performance in analysis 2 (AUC = 0.71; P = 0.002). For the contour-line-independent parameter glaucoma probability score, a statistically significant difference was also observed in the performance obtained in analysis 1 (AUC = 0.89) compared with analysis 2 (AUC = 0.65; P < 0.001). CONCLUSIONS: Estimates of diagnostic accuracy of CSLO in glaucoma can be largely different depending on the population studied and the reference standard used to define disease. Diagnostic accuracy estimates obtained from case-control studies including well-defined groups of subjects with or without disease may not be applicable to the clinically relevant population.

Adult↗

PubMed2007

The effect of atypical birefringence patterns on glaucoma detection using scanning laser polarimetry with variable corneal compensation.

PURPOSE: The purpose of this study was to investigate the effect of the presence of atypical birefringence patterns, as measured by the typical scan score (TSS), on the diagnostic accuracy of a scanning laser polarimeter (the GDx VCC; Carl Zeiss Meditec, Inc., Dublin, CA) assessed by receiver operating characteristic (ROC) curves for discriminating between glaucoma and healthy eyes. METHODS: Two hundred thirty-three glaucomatous eyes (repeatable abnormal visual fields by pattern standard deviation [PSD] and/or glaucoma hemifield test [GHT]) from 153 patients with glaucoma and 104 eyes from 71 healthy participants enrolled in the UCSD Diagnostic Innovations in Glaucoma Study (DIGS) were imaged using the GDx VCC. An ROC regression model was used to evaluate the influence of the covariates TSS; disease severity, defined as standard automated perimetry (SAP) mean deviation [MD]; and age in years on the diagnostic accuracy of the GDx parameters nerve fiber indicator [NFI], TSNIT (temporal, superior, nasal, inferior, temporal) average thickness, superior average thickness, inferior average thickness, and TSNIT standard deviation. Areas under the ROC curve were calculated for specific levels of the covariates according to the results provided by the model. RESULTS: TSS and SAP MD significantly affected the diagnostic accuracy of each investigated GDx VCC parameter. Low TSSs, indicating the presence of atypical scans, were associated with decreased accuracy. For NFI, ROC curve areas ranged from 0.749 (when TSS = 20) to 0.904 (when TSS = 100). A similar influence of TSS was found for other parameters. In addition, diagnostic accuracy increased with increasing disease severity. For instance, for NFI, ROC curve areas ranged from 0.853 (when SAP MD = -3) to 0.954 (when SAP MD = -15). CONCLUSIONS: The diagnostic accuracy of GDx VCC parameters is affected by disease severity and is adversely affected by the presence of atypical retardation patterns (i.e., decreasing TSS). GDx VCC scans with atypical scan patterns should be interpreted with caution when used in clinical practice.

Adolescent↗

PubMed2006

Retinotopic organization of primary visual cortex in glaucoma: Comparing fMRI measurements of cortical function with visual field loss.

Primary open angle glaucoma (POAG) is a progressive optic neuropathy characterized by retinal ganglion cell loss. Experimental primate glaucoma indicates neuronal degeneration of the lateral geniculate nucleus (LGN) and activity changes in the visual cortex (V1). Neuronal degeneration has also been shown in a post-mortem human study of the optic nerve, LGN and visual cortex. Functional magnetic resonance imaging (fMRI), a non-invasive means of inferring function-specific neuronal activity, provides an opportunity to evaluate glaucomatous changes in neuronal activity throughout the visual pathway in vivo. The purpose of this study is to demonstrate that the relationship between visual field loss in human POAG and the functional organization of V1 can be measured using novel fMRI analysis methods. Visual field defects were measured using standard automated perimetry (SAP). A retinotopic map of visual space was obtained for V1, and the retinotopy data was fit with a template. The template was used to project regions within the visual field onto a flattened representation of V1. Viewing through the glaucomatous vs. fellow eye was compared by alternately presenting each eye with a scotoma-mapping stimulus. The resulting blood oxygen level dependent (BOLD) fMRI response was compared to interocular differences in thresholds for corresponding regions of the visual field. The spatial pattern of activity observed in the flattened representation agreed with the pattern of visual field loss. Furthermore, the amplitude of the BOLD response was correlated on a pointwise basis with the difference in sensitivity thresholds between the glaucomatous and fellow eyes (r = 0.53, p < 0.0001). The BOLD signal in human V1 is altered for POAG patients in a manner consistent with the loss of visual function. FMRI of visual brain areas is a potential means for quantifying glaucomatous changes in neuronal activity. This should enhance our understanding of glaucoma, and could lead to new diagnostic techniques and therapies.

Animals↗

PubMed2006

Intereye concordance in locations of visual field defects in primary open-angle glaucoma: diagnostic innovations in glaucoma study.

PURPOSE: To determine the overlap in defective visual field locations between the right and left eyes of primary open-angle glaucoma patients. DESIGN: Cross-sectional retrospective analysis of data from a prospectively designed longitudinal study. PARTICIPANTS: Patients with glaucomatous optic neuropathy in at least 1 eye and 2 consecutive reliable standard automated perimetry fields within 15 months were included, yielding 468 eyes of 234 patients. METHODS: Concordance in defective visual field locations between right and left eyes were calculated as the number of overlapping locations divided by the total number of defective locations (intereye concordance ratio). Concordance ratios also were calculated within an eye over time (intraeye concordance ratio) and between unmatched pairs of fields (unmatched concordance ratio). RESULTS: Intereye concordance (0.24+/-0.02) was significantly smaller than intraeye concordance (0.37+/-0.02) and significantly larger than unmatched concordance (0.14+/-0.01). There was a significant interaction between concordance type and defect size, such that there was no difference in concordance ratios for defects of fewer than 8 locations, and the difference between intereye concordance versus intraeye concordance and unmatched concordance ratios increased with larger defect sizes. CONCLUSIONS: A spatial relationship exists between defective locations of an individual's eyes. Future studies will show whether information about the spatial relationship is useful to guide the modification of visual field test locations to improve detection of loss and perhaps also progression.

Adult↗

PubMed2006

Relationship between patterns of visual field loss and retinal nerve fiber layer thickness measurements.

PURPOSE: To investigate the association between patterns of visual field (VF) loss and retinal nerve fiber layer (RNFL) thickness measurements. DESIGN: Observational cross-sectional study. METHODS: One hundred twenty-one glaucoma patients and 65 healthy subjects from the Diagnostic Innovations in Glaucoma Study (DIGS) were included. All glaucoma patients had repeatable abnormal VFs and scanning laser polarimetry (SLP) RNFL thickness measurements. RNFL measurements were obtained from 16 equal parapapillary sectors. Patterns of VF loss were classified as arcuate, partial arcuate, nasal step, or paracentral in each VF hemifield. Logistic regression analysis was performed to determine which RNFL sectors were associated with each VF pattern. The ability of SLP to discriminate between eyes with different VF patterns and healthy eyes using receiver operating characteristic (ROC) curve analyses also was investigated. RESULTS: VF patterns in the superior hemifield were significantly associated with RNFL sectors in the temporal inferior hemiretina (P < .05). ROC curve areas for discrimination between eyes with different VF patterns and healthy eyes ranged from 0.85 to 0.95. VF patterns in the inferior hemifield were most strongly associated with temporal superior RNFL sectors (P < .05). ROC curve areas for discrimination between different VF patterns and healthy eyes ranged from 0.73 to 0.98. SLP could discriminate between apparently unaffected VF hemifields in glaucoma eyes and VF hemifields in healthy eyes. CONCLUSIONS: Parapapillary RNFL thickness was topographically related to patterns of VF loss. SLP can differentiate between apparently unaffected VF hemifields in glaucoma eyes and normal VF hemifields in healthy eyes.

Aged↗

PubMed2006

Inter-eye comparison of patterns of visual field loss in patients with glaucomatous optic neuropathy.

PURPOSE: To compare inter-eye patterns of visual field (VF) loss on standard automated perimetry (SAP) in patients with glaucomatous optic neuropathy. DESIGN: Observational cross-sectional study. METHODS: Four-hundred-and-ninety eyes of 245 patients with glaucomatous optic neuropathy in at least one eye defined by masked stereophoto review were included. Patients had two reliable SAP visual fields within fifteen months for each eye. Patterns of visual field loss were classified independently by two graders masked to all other patient information. Patterns were described as altitudinal, arcuate, partial arcuate, paracentral, nasal step, temporal wedge, or normal based on the classification system of Keltner and associates. Superior and inferior hemifields were graded separately. RESULTS: Inter-grader agreement in visual field patterns before adjudication was 97% and 94% for the worse eye (superior and inferior hemifield) and 97% and 95% for the better eye (superior and inferior hemifield). The percentage of correspondence by hemifield location was: 53% (superior-superior), 62% (inferior-inferior), 45% (superior-inferior), and 55% (inferior-superior). The highest correspondence of individual glaucomatous VF pattern between eyes was for arcuate (superior-superior) and inferior partial arcuate (inferior-inferior) defects (24% and 26%, respectively). Smaller hemifield patterns showed lower correspondence between the eyes (nasal step, paracentral, temporal wedge, 0% to 13% correspondence). CONCLUSIONS: Patterns of visual field loss between eyes often corresponded within the same VF hemifield (superior-superior, inferior-inferior) as well as between opposite hemifields (inferior-superior), although opposite hemifield correspondence was less common. More advanced visual field defects (for example, partial arcuate) showed higher correspondence rates between the eyes than less advanced defects.

Aged↗

PubMed2006

Agreement and repeatability for standard automated perimetry and confocal scanning laser ophthalmoscopy in the diagnostic innovations in glaucoma study.

PURPOSE: To assess agreement between structural and functional testing in classifying eyes as normal or abnormal and their repeatability on two consecutive visits by means of standard automated perimetry (SAP) and confocal scanning laser ophthalmoscopy. DESIGN: Analysis of selected data obtained from a prospective longitudinal observational cohort study, the Diagnostic Innovations in Glaucoma Study. METHODS: One hundred fifty-one participants with a SAP and a Heidelberg Retina Tomograph (HRT) test within a three-month window at two visits within 15 months were included. Eyes were classified by SAP and HRT at each visit. Agreement and repeatability were assessed by kappa statistics. RESULTS: At visit 1, 33 (22%) of 151 eyes had only SAP defects, 11 (7%) eyes had only HRT defects, and 35 (23%) eyes had both SAP and HRT defects. Seventy-two eyes (48%) were classified as normal by both tests. Similar results were obtained for visit 2. The agreement between SAP and HRT in classifying eyes was 70% (kappa = 0.393) at visit one and 68% (kappa = 0.363) at visit 2. Repeatability of classification by SAP alone, HRT alone, and both SAP and HRT between visits 1 and 2 was 84% (kappa = 0.693), 89% (kappa = 0.752), and 90% (kappa = 0.723), respectively. CONCLUSIONS: Agreement between SAP and HRT was only fair at both visits. Repeatability across visits was substantial for SAP alone, HRT alone, and for the combination of SAP and HRT. These results suggest that detection of particular features of glaucomatous damage depends on the technique used. Structural and functional tests appear complementary, and both should be used for early detection of glaucoma.

Female↗

PubMed2006

Baseline optical coherence tomography predicts the development of glaucomatous change in glaucoma suspects.

PURPOSE: To assess whether baseline retinal nerve fiber layer (RNFL) measurements obtained with optical coherence tomography (OCT2; Carl Zeiss Meditec, Dublin, California, USA) are predictive of the development of glaucomatous change. DESIGN: Cohort study. METHODS: Participants were recruited from the University of California, San Diego (UCSD) longitudinal Diagnostic Innovations in Glaucoma Study (DIGS). One eye was studied from each of 114 glaucoma suspects with normal standard automated perimetry (SAP) and OCT RNFL imaging at baseline. The cohort was divided into two groups based on the development of glaucomatous change (repeatable abnormal visual fields and/or a change in the stereophotographic appearance of the optic disk). Cox proportional hazards models were used to determine the predictive ability of OCT RNFL thickness measurements. RESULTS: Over a 4.2-year average follow-up period, 23 eyes (20%) developed glaucomatous changes and 91 (80%) did not. At baseline, thinner RNFL measurements, higher SAP pattern standard deviation (PSD), "glaucoma" stereophotograph assessment, and thinner central corneal thickness (CCT) were associated with the study endpoints in univariate analysis. After adjusting for age, intraocular pressure (IOP), CCT, and PSD in multivariate models, a 10 mum thinner average, superior and inferior RNFL at baseline was predictive of glaucomatous change [hazard ratio (95% CI); 1.51 (1.11 to 2.12), 1.57 (1.17 to 2.18), and 1.49, (1.19 to 1.91), respectively]. Results were consistent when stereophotographic assessment was included in multivariate analysis. CONCLUSIONS: Thinner OCT RNFL measurements at baseline were associated with development of glaucomatous change in glaucoma suspect eyes. RNFL thinning was an independent predictor of the glaucomatous change, even when adjusting for stereophotograph assessment, age, IOP, CCT, and PSD.

Cohort Studies↗

PubMed2006

Combining structural and functional testing for detection of glaucoma.

PURPOSE: To assess whether the combined use of both structural and functional tests improves discrimination between healthy and glaucomatous eyes over either type of testing alone. DESIGN: Observational cross-sectional study. PARTICIPANTS: One hundred twenty-three eyes of 123 participants enrolled in the Diagnostic Innovations in Glaucoma Study. METHODS: Because both structural and functional tests were evaluated, 2 definitions of glaucoma were used: glaucomatous visual field (VF) damage based on repeatable abnormal standard automated perimetry results (n = 43) and glaucomatous optic disc (glaucomatous optic neuropathy [GON]) based on masked assessment of optic disc stereophotographs (n = 65). Participants had scanning laser polarimetry, optical coherence tomography (OCT), and confocal scanning laser ophthalmoscopy imaging in addition to frequency-doubling technology (FDT) perimetry and short-wavelength automated perimetry (SWAP) testing completed within a 6-month interval. MAIN OUTCOME MEASURES: For each glaucoma definition, sensitivities and specificities were calculated for the best structural parameters, FDT perimetry pattern standard deviation (PSD), and SWAP PSD/glaucoma hemifield test, and then for each possible pairwise combination of one structural and one functional parameter. RESULTS: The best structural parameters for discriminating between glaucoma and control eyes were nerve fiber indicator for scanning laser polarimetry, inferior average retinal nerve fiber layer thickness for OCT, and Moorfields regression classification for confocal scanning laser ophthalmoscopy. Sensitivities and specificities for detecting glaucomatous VF damage for scanning laser polarimetry, OCT, confocal scanning laser ophthalmoscopy, FDT perimetry, and SWAP were 41.9% and 98.3%, 58.1% and 98.3%, 58.1% and 84.5%, 44.2% and 98.3%, and 65.1% and 86.2%, respectively. Adding FDT perimetry to each of the best structural parameters led to a significant (P<0.05) increase in sensitivity without a significant change in specificity compared with structural parameters alone. Adding SWAP to each of the best structural parameters led to a significant increase in sensitivity and also a significant decrease in specificity compared with each structural parameter alone. CONCLUSIONS: A combination of parameters from structural tests and functional tests can improve the sensitivity of glaucoma detection. The sensitivity and specificity desired for a particular clinical application will determine the selection of the particular diagnostic tests.

Aged↗

PubMed2006

Retinal nerve fiber layer analysis in the diagnosis of glaucoma.

PURPOSE OF REVIEW: The detection of optic disc and retinal nerve fiber layer damage and change is the cornerstone of glaucoma management. Assessment of the retinal nerve fiber layer for localized and diffuse damage has been traditionally based on clinical examination, with documentation of change primarily qualitative. With the latest improvements in optical imaging instruments, objective and quantitative measurements of the retinal nerve fiber layer are now possible. This review summarizes the results from recent cross-sectional studies evaluating the discriminating ability of automated retinal nerve fiber layer measurements to detect glaucoma, and from longitudinal studies assessing the ability to predict and monitor glaucomatous changes. RECENT FINDINGS: Numerous cross-sectional studies have documented good diagnostic accuracy of a scanning laser polarimeter (GDx VCC), the optical coherence tomograph (Stratus), and the Heidelberg Retina Tomograph retinal nerve fiber layer measurements for differentiating between healthy and glaucoma eyes. There are only limited data available on the ability of these retinal nerve fiber layer measurements to document change over time. SUMMARY: It is essential that the clinician understand the specific strengths and weaknesses of each technique so that only good quality retinal nerve fiber layer information will be used in conjunction with careful clinical examination and visual function testing for glaucoma management decisions. Longitudinal studies are needed to evaluate the ability of these instruments to document retinal nerve fiber layer change over time.

Diagnostic Imaging↗

PubMed2006

Influence of disease severity and optic disc size on the diagnostic performance of imaging instruments in glaucoma.

PURPOSE: To evaluate the influence of disease severity and optic disc size on the diagnostic accuracy of three imaging technologies for structural assessment in glaucoma: confocal scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography. METHODS: One hundred five patients with glaucoma and 61 normal subjects were recruited from the Diagnostic Innovations in Glaucoma Study (DIGS). All individuals underwent imaging with the GDx Variable Corneal and Lens Compensator (VCC; Carl Zeiss Meditec, Inc., Dublin, CA), the Heidelberg Retina Tomograph II (HRT II; Heidelberg Engineering, GmbH, Dossenheim, Germany), and the Stratus OCT (Stratus OCT; Carl-Zeiss Meditec, Inc.) within a 6-month period. Severity of disease was based on the AGIS (Advanced Glaucoma Intervention Study) visual field score. To evaluate the influence of severity of glaucoma and optic disc size on the diagnostic accuracy of the imaging instruments, the sensitivities of the tests were fitted as a function of the AGIS score and disc area, by using logistic marginal regression models. RESULTS: The severity of visual field loss had a significant influence on the sensitivity of all imaging instruments. More severe disease was associated with increased sensitivity. This influence was similar among the three instruments. With regard to optic disc area, larger optic discs were associated with decreased sensitivity for the Stratus OCT parameter Average Thickness and the GDx VCC parameter Nerve Fiber Indicator, whereas small optic discs were associated with increased sensitivity. For the HRT II parameter Moorfields regression analysis classification, an inverse effect was observed. CONCLUSION: The diagnostic performances of the GDx VCC, HRT II, and Stratus OCT were significantly influenced by the severity of the disease and optic disc size. These covariates should be taken into account when comparing the performances of these tests for glaucoma diagnosis.

Aged↗

PubMed2006

A statistical approach to the evaluation of covariate effects on the receiver operating characteristic curves of diagnostic tests in glaucoma.

PURPOSE: To describe an approach for the evaluation of covariate effects on receiver operating characteristic (ROC) curves and to apply this methodology to the investigation of the effects of disease severity and age on the diagnostic performance of frequency doubling technology (FDT) and standard automated perimetry (SAP) visual function tests for glaucoma detection. METHODS: The study included 370 eyes of 211 participants, with 174 eyes of 110 patients having glaucomatous optic neuropathy and 196 eyes of 101 subjects being normal. All patients underwent visual function testing with FDT 24-2 Humphrey Matrix and SAP SITA (Carl Zeiss Meditec, Inc., Dublin, CA). Disease severity was evaluated by the amount of neuroretinal rim loss assessed by confocal scanning laser ophthalmoscopy. An ROC regression model was fitted to evaluate the influence of disease severity and age on the diagnostic performance of the pattern SD (PSD) index from FDT 24-2 and SAP SITA. RESULTS: After adjustment for age, the areas under the ROC curves (AUCs) for SAP SITA PSD for 10%, 30%, 50%, and 70% loss of neuroretinal rim area were 0.638, 0.756, 0.852, and 0.920, respectively. Corresponding values for FDT 24-2 PSD were 0.766, 0.857, 0.922, and 0.962. For 10% and 30% rim loss, FDT 24-2 PSD had a significantly larger AUC than did SAP SITA PSD. CONCLUSIONS: A regression methodology to evaluate covariate effects on ROC curves can be useful for assessment of diagnostic tests in glaucoma. Using the proposed methodology, a significantly better performance of FDT 24-2 compared to SAP SITA for diagnosis of early glaucoma was demonstrated.

Age Factors↗

PubMed2006

Structure-function relationships using confocal scanning laser ophthalmoscopy, optical coherence tomography, and scanning laser polarimetry.

PURPOSE: To assess the strength of the association between retinal nerve fiber layer (RNFL) thickness and optic disc topography measured with confocal retinal tomography (HRT II; Heidelberg Engineering, Dossenheim, Germany), optical coherence tomography (StratusOCT; Carl Zeiss Meditec, Inc., Dublin, CA), and scanning laser polarimetry (GDx with variable corneal compensator, VCC; Carl Zeiss Meditec, Inc.), and visual field (VF) sensitivity and to determine whether this association is better expressed as a linear or nonlinear function. METHODS: One hundred twenty-seven patients with glaucoma or suspected glaucoma and 127 healthy eyes from enrollees in the Diagnostic Innovations in Glaucoma Study (DIGS) were tested on HRT II, StratusOCT, GDx VCC, and standard automated perimetry (SAP, with the Swedish Interactive Thresholding Algorithm [SITA]) within 3 months of each other. Linear and logarithmic associations between RNFL thickness (HRT II, StratusOCT, and GDx VCC) and neuroretinal rim area (HRT II) and SAP sensitivity expressed in decibels were determined globally and for six RNFL/optic disc regions (inferonasal, inferotemporal, temporal, superotemporal, superonasal, and nasal) and six corresponding VF regions (superior, superonasal, nasal, inferonasal, inferior, and temporal). RESULTS: The associations (R2) between global and regional RNFL/optic disc measurements and VF sensitivity ranged from <0.01 (temporal RNFL, nasal VF, and nasal RNFL, temporal VF; linear and logarithmic associations) to 0.26 (inferotemporal RNFL, superonasal VF; logarithmic association) for HRT II; from 0.02 (temporal RNFL, nasal VF; linear association) to 0.38 (inferotemporal RNFL, superonasal VF; logarithmic association) for OCT; and from 0.03 (temporal RNFL, nasal VF; linear association) to 0.21 (inferotemporal RNFL, superonasal VF; logarithmic association) for GDx. Structure-function relationships generally were strongest between the inferotemporal RNFL-optic disc sector and the superonasal visual field and were significantly stronger for StratusOCT RNFL thickness than for other instruments in this region. Global associations (linear and logarithmic) were significantly stronger using OCT compared with HRT. In most cases, logarithmic fits were not significantly better than linear fits when visual sensitivity was expressed in log units (i.e., decibels). CONCLUSIONS: These results suggest that structure-function associations are strongest with StratusOCT measurements and are similar between HRT II and GDx VCC and these associations are generally no better expressed logarithmically than linearly when healthy, suspect, and glaucomatous eyes are considered.

Female↗

PubMed2006

Identifying glaucomatous vision loss with visual-function-specific perimetry in the diagnostic innovations in glaucoma study.

PURPOSE: To compare the diagnostic results of four perimetric tests and to identify useful parameters from each for determining abnormality. METHODS: One hundred eleven eyes with glaucomatous optic neuropathy (GON), 31 with progressive optic neuropathy (PGON) 53 with ocular hypertension, and 51 with no disease were included (N = 246). Visual field results were not used to classify the eyes. Short-wavelength automated perimetry (SWAP), frequency-doubling technology perimetry (FDT), high-pass resolution perimetry (HPRP), and standard automated perimetry (SAP) were performed. Receiver operating characteristic (ROC) curves were used to compute the areas under the curves (AUC) and sensitivity levels at given specificities for a variety of abnormality criteria. The agreement among tests for abnormality, location, and extent of visual field deficit were assessed. RESULTS: AUC analysis: When the normal group was compared with the GON group, the FDT pattern SD (PSD) area was larger than the HPRP PSD (P = 0.020), and the FDT area of total deviation (TD) <5% was larger than the HPRP mean deviation (MD; P = 0.004). When the normal group was compared with the PGON group, the FDT area of pattern deviation (PD) <5% was larger than the SWAP PSD (P = 0.020). A difference from previous work was that AUCs for PSD or the best SAP were not significantly poorer than those in the function-specific tests. At set specificities, FDT yielded higher sensitivities than all other tests for all parameters. The agreement among tests for abnormality was fair to moderate (kappa = 247-0.563). When loss was present on more than one test, the quadrant of the visual field affected was the same in 95% (79/83) of eyes. The number of eyes identified and number of abnormal quadrants increased across groups with increasing certainty of glaucoma. CONCLUSIONS: At equal specificity, no single perimetric test was always affected, whereas others remained normal. Several parameters at suggested criterion values provided good sensitivity and specificity. FDT showed the highest sensitivity overall, with SAP performing better than in prior reports. Of note, the same area of the retina was identified as damaged in all tests.

Adult↗

PubMed2005

Agreement among 3 optical imaging methods for the assessment of optic disc topography.

PURPOSE: To assess the agreement of disc topography measurements between the Heidelberg Retina Tomograph (HRT II), Retinal Thickness Analyzer (RTA), and Optical Coherence Tomograph (StratusOCT). DESIGN: Observational cross-sectional study. PARTICIPANTS: Forty-two randomly chosen eyes of 42 subjects. METHODS: Each subject underwent HRT II, RTA, and StratusOCT examination. Two experienced examiners drew the contour lines for the HRT II and RTA. Bland and Altman plots were used to evaluate agreement for each topographic parameter among the instruments. The Spearman coefficient of rank correlation was evaluated for each topographic parameter. MAIN OUTCOME MEASURES: Agreement in the measurement of optic disc topography among 3 imaging instruments, as evaluated by regression-based 95% limits of agreement. RESULTS: For optic disc area, the agreement between HRT II-RTA and StratusOCT-RTA revealed the existence of proportional bias, indicated by significant slopes of the regression lines (P = 0.01 and P = 0.02, respectively). The 95% limits of agreement between instruments varied with the actual optic disc size measurement. Heidelberg Retina Tomograph disc area measurements tended to be consistently lower than StratusOCT disc area measurements (fixed bias). The Spearman correlation coefficient between the instruments ranged from r = 0.35 (rim area, HRT II-StratusOCT) to r = 0.91 (cup area, HRT II-RTA). CONCLUSIONS: Moderate to high correlation was found in measurements of optic disc topography among different instruments. However, the analysis of agreement indicated important discrepancies among instruments. Therefore, these instruments should not be used interchangeably to obtain measurements of the optic disc for glaucoma diagnosis.

Aged↗

PubMed2005

Validation of a predictive model to estimate the risk of conversion from ocular hypertension to glaucoma.

OBJECTIVES: To develop and validate a predictive model to estimate the risk of conversion from ocular hypertension to glaucoma. METHODS: Predictive models for the 5-year risk of conversion to glaucoma were derived from the results of the Ocular Hypertension Treatment Study (OHTS). The performance of these models was assessed in an independent population of 126 subjects with ocular hypertension from a longitudinal study (Diagnostic Innovations in Glaucoma Study [DIGS]). The performance of the OHTS-derived models was assessed in the DIGS cohort according to equality of regression coefficients, discrimination (c-index), and calibration. RESULTS: Thirty-one patients (25%) developed glaucoma during follow-up. Hazard ratios for DIGS- and OHTS-derived predictive models were similar for age, intraocular pressure, central corneal thickness, vertical cup-disc ratio, and pattern standard deviation but were significantly different for the presence of diabetes mellitus. When applied to the DIGS population, the OHTS-derived predictive models had reasonably good discrimination (c-indexes of 0.68 [full model] and 0.73 [reduced model]) and calibration. CONCLUSIONS: The OHTS-derived predictive models performed well in assessing the risk of glaucoma development in an independent population of untreated subjects with ocular hypertension. A risk scoring system was developed that allows calculation of the 5-year risk of glaucoma development for an individual patient.

Disease Progression↗

PubMed2005

Differences in visual function and optic nerve structure between healthy eyes of blacks and whites.

OBJECTIVE: To investigate differences in visual function, optic disc topography, and retinal nerve fiber layer (RNFL) thickness between healthy eyes of blacks and whites. METHODS: Visual function was assessed in healthy eyes of 50 blacks and 50 whites using standard automated perimetry, short-wavelength automated perimetry, and frequency doubling technology perimetry. Optic disc topography and RNFL thickness were measured using the Heidelberg Retina Tomograph and the optical coherence tomograph. RESULTS: Mean standard automated perimetry mean deviations were within the normal range for both groups. Blacks had worse mean deviation values than whites using frequency doubling technology perimetry (mean +/- SD, -1.8 +/- 3.2 dB vs -0.1 +/- 2.4 dB), blacks had larger optic disc areas than whites using the Heidelberg Retina Tomograph (mean +/- SD, 2.1 +/- 0.4 mm2 vs 1.7 +/- 0.4 mm2), the RNFL of blacks was thicker than that of whites by 16.91 microm superiorly and 10.10 microm inferiorly using optical coherence tomography, and blacks had slightly higher intraocular pressures than whites (mean +/- SD, 16.5 +/- 2.5 mm Hg vs 15.2 +/- 3.2 mm Hg) and thinner central corneas (mean +/- SD, 540.5 +/- 43.2 microm vs 560.9 +/- 35.5 microm). No racial differences were found in mean RNFL thickness, pattern standard deviation on all tests, or any of the short-wavelength automated perimetry variables. CONCLUSIONS: Minimal racial differences in visual function were found, but race significantly affected optic disc topography and superior and inferior RNFL thickness measurements in healthy eyes. The racial differences observed for intraocular pressure could theoretically increase after correcting for central corneal thickness. Prospective studies are needed to further investigate these findings.

Anthropometry↗

PubMed2005

Baseline topographic optic disc measurements are associated with the development of primary open-angle glaucoma: the Confocal Scanning Laser Ophthalmoscopy Ancillary Study to the Ocular Hypertension Treatment Study.

OBJECTIVE: To determine whether baseline confocal scanning laser ophthalmoscopy (CSLO) optic disc topographic measurements are associated with the development of primary open-angle glaucoma (POAG) in individuals with ocular hypertension. METHODS: Eight hundred sixty-five eyes from 438 participants in the CSLO Ancillary Study to the Ocular Hypertension Treatment Study with good-quality baseline CSLO images were included in this study. Each baseline CSLO parameter was assessed in univariate and multivariate proportional hazards models to determine its association with the development of POAG. RESULTS: Forty-one eyes from 36 CSLO Ancillary Study participants developed POAG. Several baseline topographic optic disc measurements were significantly associated with the development of POAG in both univariate and multivariate analyses, including larger cup-disc area ratio, mean cup depth, mean height contour, cup volume, reference plane height, and smaller rim area, rim area to disc area, and rim volume. In addition, classification as "outside normal limits" by the Heidelberg Retina Tomograph classification and the Moorfields Regression Analysis classifications (overall, global, temporal inferior, nasal inferior, and superior temporal regions) was significantly associated with the development of POAG. Within the follow-up period of this analysis, the positive predictive value of CSLO indexes ranged from 14% (Heidelberg Retina Tomograph classification and Moorfields Regression Analysis overall classification) to 40% for Moorfields Regression Analysis temporal superior classification. CONCLUSIONS: Several baseline topographic optic disc measurements alone or when combined with baseline clinical and demographic factors were significantly associated with the development of POAG among Ocular Hypertension Treatment Study participants. Longer follow-up is required to evaluate the true predictive accuracy of CSLO measures.

False Positive Reactions↗