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Alessandro Jammal, Nara Gravina Ogata, Fabio Bernardi Daga, Ricardo Y Abe, Vital P Costa, Felipe Medeiros; What amount of visual field loss is associated with visual impairment in glaucoma?. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5101.
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© ARVO (1962-2015); The Authors (2016-present)
Previous studies have reported significant associations between quality of life (QoL) scores derived from the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) and the severity of visual field defects assessed by standard automated perimetry (SAP) in glaucoma. However, it is still not clear how much damage on SAP needs to be present for patients to exhibit a significant decline on vision-related quality of life. This study proposes a new methodology for clarifying at which point patients with glaucoma develop significant disability from the disease.
263 patients with glaucoma were included. Vision-related disability was assessed by NEI VFQ-25. A latent class analysis (LCA) model was applied to categorize NEI VFQ-25 results, and SAP mean deviation (MD) and binocular mean sensitivity (MS) values were investigated in each class. The optimal number of classes was defined based on the lowest scores for Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), goodness of fit from Lo-Mendell-Rubin test and parametric bootstrapped likelihood ratio test, as well as classification of precision, interpretability and clinical utility.
The model with two classes, disabled and nondisabled, had the best fit. The model had an entropy of 0.965. The disabled group was represented by 48 (18%) patients and had mean MD of the better eye of -5.98 ± 6.31 dB versus -2.51 ± 3.92 dB in the nondisabled group (P < 0.001). For the worse eye, corresponding values were -13.36 ± 9.31dB and -6.05 ± 6.02 dB, respectively (P < 0.001). Mean NEI VFQ-25 scores were 71.88 ± 11.22 in the disabled group versus 93.84 ± 4.56 in the nondisabled group (P < 0.001). (Table 1)
Application of a latent class model to analyze patient-reported QoL outcomes in glaucoma allowed the investigation of the amount of visual field loss associated with significant disability in the disease.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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