Impact of Visual Field Loss on Vision-Specific Quality of Life in African Americans: The African American Eye Disease Study

Abstract

Purpose: To elucidate how visual field loss (VFL) impacts self-reported vision-specific quality of life (VSQOL) in African Americans, who experience a disproportionate burden of visual impairment.

Design: Cross-sectional, population-based cohort.

Methods: Eligible participants (n = 7,957) were recruited who self-identified as African American, were aged 40 years or older, and resided in Inglewood, California, USA. A total of 6,347 participants (80.0%) completed clinical eye examinations. Total mean deviation (MD) of VFL was measured bilaterally as decibels (dB) using the Humphrey SITA Standard 24-2 test. VSQOL was measured using the National Eye Institute Visual Function Questionnaire (NEI-VFQ 25) and scored using item response theory (IRT).

Results: Participants with reliable data (n = 5,121) had a mean age of 60.7 years (standard deviation 11.0); those with worse VFL were older; had more comorbidities, lower income, less education, and worse visual acuity; and were more likely to be unemployed and depressed. Using IRT analysis, a change in VF of 6.2 (95% confidence interval [CI]: 5.3, 7.7) dB and 9.2 (95% CI: 7.5, 11.9) dB was necessary to observe a meaningful (5-point) difference in vision-related task and emotional well-being scores, respectively. VFL had the greatest impact on self-reported driving ability (6.0 dB [95% CI: 5.2, 7.1]), followed by satisfaction with general vision, near vision, vision-related mental health, and peripheral vision.

Conclusions: The strongest impact of VFL reported by African Americans was on their ability to complete visual tasks, especially for driving. An effect of VFL on emotional well-being also was observed, but the magnitude of association was about 50% lower for well-being compared to that of task.

Figure 1:

LOWESS plot of predicted VSQOL IRT composite scores regressed on VFL in the BSE LOWESS = Locally Weighted Scatterplot Smoothing; NEI-VFQ-25 = National Eye Institute Visual Function Questionnaire 25-ltem; IRT = Item Response Theory; VFL = Visual Field Loss; MD = Mean Deviation; dB = Decibels; BSE = Better-Seeing Eye The LOWESS smoothing parameter is 0.6. Gray bars represent 95% confidence limits of the predicted NEI-VFQ-25 IRT composite scores. Linear regression models were adjusted for age, number of comorbidities, sex (female), education (< 4 years of college), working status (unemployed), income (≤ $20,000), has health insurance (yes), has vision insurance (yes), visual acuity loss (20/40 or worse), and depression (a good bit of the time or more in the last 4 weeks).

Figure 2:

Effect sizes comparing VSQOL in each VFL severity category to those without VFL VSQOL = Vision-Specific Quality of Life; AFEDS = African American Eye Disease Study; VFL = Visual Field Loss; CTT = Classical Test Theory; IRT = Item Response Theory; ANCOVA = Analysis of Covariance; ES = Effect Sizes; NEI-VFQ-25 = National Eye Institute Visual Function; SF-12 = 12-Item Short-Form Health Survey ES below 0.20 are negligible and not shown. ES from 0.20 to less than 0.50 are considered small, 0.50 to less than 0.80 are medium, and 0.80 or more are large. ES were calculated from ANCOVA models as the difference in adjusted mean QOL scores for each VFL severity category and the no VFL category, divided by the standard deviation of QOL score in the no VFL group. ES are shown for the NEI-VFQ-25 CTT composite, the IRT task and well-being composites, all 11 CTT subscales, and the general health item; CTT subscales are grouped by task or well-being and ordered by descending ES in the bilateral moderate/severe comparison. The SF-12 component scores are also shown. VFL severity was stratified into five categories: no VFL (mean deviation [MD] > 2 decibels [dB] in both eyes), unilateral mild VFL (−6 dB 2 dB in the other eye; or 6 dB < MD < 2 dB in one eye, MD < 6 dB in the other eye), and bilateral moderate-to-severe VFL (MD < 6 dB in both eyes). *NEI-VFQ-25 item response theory and classical test theory composite scores are marked for emphasis. ^||Scores could be generated for only 4,574 of the participants who reported that they were currently driving or had driven in the past.