![]() ![]() Some specific rules were added regarding the spatial homogeneity and clinical coherence of the clusters: (1) To maintain the spatial homogeneity of clusters (geographical continuity: a score had to relate to neighboring measurements), constraints were defined that restricted certain moves-that is, if a measurement was separated spatially from its cluster by another measurement, the former was moved to the nearest cluster. This iterative process continued until the system stabilized (i.e., no further movement was necessary). When this was not the case, the variable was moved to other scores to maximize its correlation. A variable was regarded as correctly classified when its correlation with a score was higher than that with any other score. Further analyses, based on longitudinal data, must be performed to confirm these findings.Ĭorrelations between each of the 52 variables and the scores were computed. It was possible to discriminate between clinical subgroups. Six well-separated, optimal scores were obtained from the Humphrey perimetry matrix. Scores of AC were lower in NS, NI, and TS PCSS was less in PCS BSE scores were less in TS and TI NaS scores were less in NS and NI.Ĭ onclusions. The six scores decreased sequentially from IVF to DD to AD. Six scores were identified: four peripheral scores (nasal superior, NS nasal inferior, NI temporal superior, TS and temporal inferior, TI) and two paracentral scores (PCSs superior, PCSS and inferior, PCSI). The average mean deviation was −9.2 dB and pattern standard deviation was 6.5 dB. Patients older than 60 years comprised 53.3% of the sample. Clinical predictability of the derived scores was checked by comparing clinical groups (ANOVA). Unidimensionality was checked by a stepwise Cronbach α curve. The number and content of constituent variable scores were identified by principal components analysis followed by Varimax Rotation and simple clustering, taking spatial distribution homogeneity and visual system anatomy into account. Visual field data of 437 patients were collected and classified by a glaucoma specialist into seven clinical groups: irregularities of VF (IVF), nasal step (NaS), arcuate scotoma (AC), paracentral scotoma (PCS), blind-spot enlargement (BSE), diffuse deficit (DD), and advanced deficit (AD). To extract unidimensional, well-separated latent scores that are anatomically and clinically valid from 52 standardized variables collected by Humphrey visual field (VF) perimetry (Carl Zeiss Meditec, Dublin, CA). ![]()
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