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Heather Livengood, Gadi Wollstein, Hiroshi Ishikawa, Mengfei Wu, Joel Schuman; Function and not structure in glaucoma is associated with Rasch-calibrated VFQ-25 scales. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4960. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Glaucoma affects subjects’ vision-related quality of life (VRQoL). VRQoL is an important subject-reported outcome which can be used to guide future evaluation of activities affected by glaucoma in order to enable timely treatment and/or referral to services such as vision rehabilitation. The National Eye Institute Visual Functioning Questionnaire-25 (VFQ-25) is commonly used in ophthalmic research. This study (1) uses Rasch analysis to select VFQ-25 items with high differential capability of person ability and (2) tests the association between Rasch-calibrated VFQ-25 visual functioning and socioemotional scales vs. measures of structure and function in glaucoma.
We recruited adults 50 years and older with glaucoma, no other ocular comorbidities, who underwent comprehensive ophthalmic evaluation, visual field (VF) testing, OCT, and completed the VFQ-25. Better-eye VF mean deviation (MD) and OCT parameters were analyzed. Rasch analysis was used to transform the item response in VFQ-25 from ordinal to linear scale while accounting for item hierarchical order based on the level of person ability. Multivariable regression analyses using Rasch-calibrated scales determined the association of VFQ-25 visual functioning and socioemotional scales with measures of structure-function, adjusting for the covariates age, sex, race, glaucoma symptoms, depressive symptoms, and best-corrected visual acuity.
77 subjects of average age 68 ± 9.6 years and better-eye MD of -3.7 ± 6.3 dB, OCT's retinal nerve fiber layer of 76.1 ± 13.3 μm, and ganglion cell inner plexiform layer of 69.8 ± 10.7 μm were enrolled. Rasch analysis selected 14 VFQ-25 items with high differential capability, of which 4 items fit the visual functioning scale and 10 items fit the socioemotional scale (Figure). Both the visual functioning and socioemotional scales were significantly associated with MD of the better eye (P ≤ 0.03). No OCT parameters were signifantly associated with either the visual functioning or socioemotional scales. Glaucoma symptoms had a significant association with both scales.
VFQ-25 visual functioning and socioemotional scales are associated with glaucoma severity as defined by VF MD. Neither scale was associated with a structural OCT measure. This finding is important in the use of structural and functional information measures in glaucoma to guide intervention decisions.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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