Biomedical subjects

Rupert R Bourne

Publications and source records attributed to Rupert R Bourne.

4 recordsLinked to original sources

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.

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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.

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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.

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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.

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