Abstract
Purpose: :
Decreased vision-related quality of life in glaucoma has been well established in previous studies using the 51 and 25 item versions of the National Eye Institute Visual Function Questionnaire (VFQ). This study examines how glaucoma subjects in the population-based National Health and Nutrition Examination Survey (NHANES) respond to the abbreviated 9-item version of the questionnaire (VFQ-9).
Methods: :
During the 2005-2008 NHANES survey, subjects over the age of 40 underwent frequency doubling perimetry testing (N30-5 FDT) and optic disc photographs. The definition for glaucoma was: 1) having 2 or more abnormal FDT points on two tests in the same eye with 1 abnormal point being the same in both tests and 2) a cup-to-disc ratio (CDR) or CDR asymmetry between eyes greater than or equal to 97.5th percentile for the normal NHANES population. The VFQ-9 administered to each subject consists of general vision, well being/mental health, near vision, distance vision, driving, role limitation, and peripheral vision subscales.
Results: :
5429 subjects completed both the FDT and optic disc photographs. Of these, 178 were classified as having glaucoma. Compared to other subjects over the age of 40, glaucoma subjects had similar mean composite VFQ-9 scores. They had, however, lower mean scores on the distance vision (glaucoma - 88.4, 95% CI: 84.3;92.5 vs. none - 93.6, 95% CI: 93.0;94.1) and peripheral vision subscales (glaucoma - 94.0, 95% CI: 91.7;96.3 vs. none - 97.0, 95% CI: 96.7;97.4). Subjects who reported having a diagnosis of glaucoma but did not meet clinical criteria had a lower mean composite VFQ-9 score (88.1, 95% CI: 84.9;91.4) than those who did not report a diagnosis of glaucoma and did not have clinical evidence of the disease (92.4, 95% CI: 92.0;92.8). Scores for those who clinically had glaucoma and self-reported having the disease trended towards being lower than their counterparts who clinically had glaucoma but were unaware of their diagnosis.
Conclusions: :
In the NHANES, glaucoma subjects do not exhibit differing composite VFQ-9 scores from controls but do have lower peripheral and distance vision subscale scores. Belief of having a diagnosis of glaucoma results in lower quality of life scores whether the subject has clinical signs of the disease or not. Given its shortened nature, the VFQ-9 may be suitable for use in evaluating glaucoma subjects’ quality of life in large population-based surveys if attention is paid to subscale scores.
Keywords: quality of life