1,720,969 research outputs found
AGREEMENT TO DETECT GLAUCOMATOUS VISUAL FIELD PROGRESSION BY USING GLAUCOMA PROGRESSION ANALYSIS AND STANDARD HUMPHREY PRINTOUT
No full textEvaluation of threshold estimation and learning effect of two perimetric strategies, SITA Fast and CLIP, in damaged visual fields.
No full textPURPOSE. The threshold estimation, learning effect, and between-algorithm differences of the Fast
Swedish Interactive Thresholding Algorithm (SITA Fast), of the Humphrey Field Analyzer (HFA), and
the Continuous Light Increment Perimetry (CLIP) strategy of the Oculus Twinfield perimeter were
evaluated in damaged visual fields.
METHODS. Twenty-one glaucomatous patients with damaged visual fields (MD worse than –8 dB) underwent
Oculus Full Threshold (FT), Humphrey FT, SITA Fast, and CLIP 30-2 perimetric examinations.
All the tests were repeated in a second session at least 3 days later. The point-wise differences
in absolute sensitivity and of the total deviation plot values between FT and fast algorithms,
between fast algorithms and the learning effect were evaluated (Wilcoxon test and Bland-Altman
analysis).
RESULTS. The average point-wise sensitivity difference between SITA Fast and HFA FT strategy (0.84
dB) was significantly lower than that found between CLIP and Oculus FT strategy (1.71 dB). Between-
algorithm point-wise differences of the total deviation plot values of the fast strategies were
not significantly different. Learning effect for SITA Fast (0.67 dB) was higher than that found for
CLIP (0.39 dB). Test time for SITA (367±71 sec) and CLIP (453±98 sec) were about 55% and 35%,
respectively, shorter (p<0.001) than those found with FT algorithms. The acceptance for fast algorithms
and particularly for CLIP was significantly better.
CONCLUSIONS. The two fast strategies, even though using very different algorithms, showed good
threshold estimation compared to FT strategies with a consistent time saving in damaged visual
fields
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Comparison between discriminant analysis models and "glaucoma probability score" for the detection of glaucomatous optic nerve head changes
No full textPurpose: The aim of this study was to evaluate and compare 4 different discriminant analysis formulas and the new Glaucoma Probability Score (GPS) for the detection of morphometric optic nerve head changes in chronic open-angle glaucoma. Methods: This is a prospectively planned cross-sectional study. Two hundred and fourteen consecutive eyes were recruited into this study. For each patient, the eyes were evaluated by a slit lamp examination, and the visual fields were assessed by a Humphrey Field Analyzer 750 (HFA, Humphrey Inc, San Leandro, CA), using the standard full threshold 24-2 (Swedish Interactive Threshold Algorithm) program. The optic nerve heads were morphometrically evaluated using the Heidelberg Retina Tomograph 3 (HRT 3, Heidelberg Engineering, Heidelberg, Germany; software version 3.0). From the HRT data, 4 discriminant analysis formulas and the GPS were considered. All data were analyzed by Student t test and Pearson r coefficient. A linear regression model was also used to determine the independent contribution of variables included in the model. Sensitivity, specificity, diagnostic precision, and receiver operating characteristic curve areas were calculated for all the 5 methods examined. [kappa] statistic was used to study the agreement among, and between, the 5 different methods. Results: One hundred and nineteen normal eyes and 95 eyes with primary open-angle glaucoma were included in the study. No significant difference was found between the 2 study subgroups in both age and refractive error. Significant (P0.001) correlations were found between visual field indices and the HRT parameters. Sensitivity, specificity, and diagnostic precision of the 4 formulas ranged between 50% and 99.16%. Bathija et al's formula had the highest diagnostic precision, followed by Mikelberg's formula. Using [kappa] statistics, [kappa] ranged from 0.177 to 0.528 when comparing each single discriminant formula with the GPS. Conclusions: The GPS showed similar sensitivity and specificity to the Mikelberg and Bathija formulas; this method is a promising one for differentiating between healthy and glaucomatous eyes, requiring no subjective user input
The Sound of Scotoma: Audio Space Representation Reorganization in Individuals With Macular Degeneration
No full textBlindness is an ideal condition to study the role of visual input on the development of spatial representation, as studies have shown how audio space representation reorganizes in blindness. However, how spatial reorganization works is still unclear. A limitation of the study on blindness is that it is a “stable” system and it does not allow for studying the mechanisms that subtend the progress of this reorganization. To overcome this problem here we study, for the first time, audio spatial reorganization in 18 adults with macular degeneration (MD) for which the loss of vision due to scotoma is an ongoing progressive process. Our results show that the loss of vision produces immediate changes in the processing of spatial audio signals. In individuals with MD, the lateral sounds are “attracted” toward the central scotoma position resulting in a strong bias in the spatial auditory percept. This result suggests that the reorganization of audio space representation is a fast and plastic process occurring also later in life, after vision loss
Discrimination between normal and glaucomatous eyes with Heidelberg Retina Tomograph (HRT-3) parameters and classification systems
No full textExploring the Heidelberg Retinal Tomograph 3 Diagnostic Accuracy across Disc Sizes and Glaucoma Stages: a Multicenter Study
No full textPurpose: To investigate and compare the diagnostic accuracy of the Heidelberg Retinal Tomograph 3 (HRT3) diagnostic algorithms and establish whether they are affected by optic disc size and glaucoma severity.
Design: Multicenter cross-sectional evaluation of diagnostic tests.
Participants: Two hundred forty-two eyes from 139 normal subjects and 103 glaucomatous patients classified by the presence of a repeatable visual field (VF) defect.
Testing: Eyes were imaged by the HRT3. The diagnostic accuracies of Moorfields regression analysis (MRA) and the glaucoma probability score (GPS) was explored by sensitivity and specificity and area under the receiver operating characteristics curves (AUC). The analysis was performed globally and by optic disc size quartiles and by 3 VF severity groups.
Main Outcome Measures: Sensitivity, specificity, and AUC.
Results: The GPS showed a sensitivity (80% vs. 77%) similar to and a specificity (57% vs. 67%) lower than that of MRA Result. It showed a higher specificity in small discs than MRA Result (77% vs. 68%) but a low to very low specificity in medium to very large discs (medium, 61%; large, 50%; very large, 26%). Moorfields regression analysis Global showed the highest sensitivity and specificity (68% and 78%) in very large discs. R. Burke linear discriminant function (RB-LDF) and cup shape measure (CSM) showed the best and least variable AUC across optic nerve head sizes and glaucoma stages. The sensitivity of both MRA and the GPS decreased at the earlier glaucoma stages. The MRA and GPS agreement was moderate throughout the entire population and in small discs and early stage, whereas it was weaker among the other disc size and glaucoma stage subgroups.
Conclusions: HRT3 diagnostic algorithms’ accuracy is moderate. The GPS is less specific and more influenced by disc size than MRA. Cup shape measure and the RB-LDF offer the best and less variable performances across different disc sizes and glaucoma stages
Comparison between discriminant analysis models and "glaucoma probability score" for the detection of glaucomatous optic nerve head changes
No full textPURPOSE: The aim of this study was to evaluate and compare 4 different discriminant analysis formulas and the new Glaucoma Probability Score (GPS) for the detection of morphometric optic nerve head changes in chronic open-angle glaucoma. METHODS: This is a prospectively planned cross-sectional study. Two hundred and fourteen consecutive eyes were recruited into this study. For each patient, the eyes were evaluated by a slit lamp examination, and the visual fields were assessed by a Humphrey Field Analyzer 750 (HFA, Humphrey Inc, San Leandro, CA), using the standard full threshold 24-2 (Swedish Interactive Threshold Algorithm) program. The optic nerve heads were morphometrically evaluated using the Heidelberg Retina Tomograph 3 (HRT 3, Heidelberg Engineering, Heidelberg, Germany; software version 3.0). From the HRT data, 4 discriminant analysis formulas and the GPS were considered. All data were analyzed by Student t test and Pearson r coefficient. A linear regression model was also used to determine the independent contribution of variables included in the model. Sensitivity, specificity, diagnostic precision, and receiver operating characteristic curve areas were calculated for all the 5 methods examined. κ statistic was used to study the agreement among, and between, the 5 different methods. RESULTS: One hundred and nineteen normal eyes and 95 eyes with primary open-angle glaucoma were included in the study. No significant difference was found between the 2 study subgroups in both age and refractive error. Significant (P<0.001) correlations were found between visual field indices and the HRT parameters. Sensitivity, specificity, and diagnostic precision of the 4 formulas ranged between 50% and 99.16%. Bathija et al's formula had the highest diagnostic precision, followed by Mikelberg's formula. Using κ statistics, κ ranged from 0.177 to 0.528 when comparing each single discriminant formula with the GPS. CONCLUSIONS: The GPS showed similar sensitivity and specificity to the Mikelberg and Bathija formulas; this method is a promising one for differentiating between healthy and glaucomatous eyes, requiring no subjective user input. © 2008 by Lippincott Williams & Wilkins
- …
