Psychometrics of a new questionnaire to assess glaucoma adherence: the Glaucoma Treatment Compliance Assessment Tool (an American Ophthalmological Society thesis).

PURPOSE: To report the psychometrics of the Glaucoma Treatment Compliance Assessment Tool (GTCAT), a new questionnaire designed to assess adherence with glaucoma therapy. METHODS: We developed the questionnaire according to the constructs of the Health Belief Model. We evaluated the questionnaire using data from a cross-sectional study with focus groups (n = 20) and a prospective observational case series (n=58). Principal components analysis provided assessment of construct validity. We repeated the questionnaire after 3 months for test-retest reliability. We evaluated predictive validity using an electronic dosing monitor as an objective measure of adherence. RESULTS: Focus group participants provided 931 statements related to adherence, of which 88.7% (826/931) could be categorized into the constructs of the Health Belief Model. Perceived barriers accounted for 31% (288/931) of statements, cues-to-action 14% (131/931), susceptibility 12% (116/931), benefits 12% (115/931), severity 10% (91/931), and self-efficacy 9% (85/931). The principal components analysis explained 77% of the variance with five components representing Health Belief Model constructs. Reliability analyses showed acceptable Cronbach's alphas (>.70) for four of the seven components (severity, susceptibility, barriers [eye drop administration], and barriers [discomfort]). Predictive validity was high, with several Health Belief Model questions significantly associated (P <.05) with adherence and a correlation coefficient (R (2)) of .40. Test-retest reliability was 90%. CONCLUSION: The GTCAT shows excellent repeatability, content, construct, and predictive validity for glaucoma adherence. A multisite trial is needed to determine whether the results can be generalized and whether the questionnaire accurately measures the effect of interventions to increase adherence.

The impact of eyeglasses on vision-related quality of life in American Indian/Alaska Natives.

PURPOSE: To determine the change in vision-related quality-of-life scores after providing eyeglasses to American Indian/Alaska Natives with undercorrected refractive error. STUDY DESIGN: Prospective, comparative (nonrandomized) interventional study. METHODS: We compared a group with undercorrected refractive error to a control group who did not need a change in eyeglasses. Undercorrected refractive error was defined as distance visual acuity 20/40 or worse in the better-seeing eye that could be improved by at least 2 lines in Snellen visual acuity. Intervention was the provision of new glasses to the undercorrected refractive error group members, based on results of manifest refraction. The main outcome measures were the differences in the 25-Item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) scores from baseline (Time 1) to the time after providing eyeglasses (Time 2). RESULTS: The NEI VFQ-25 median Composite score at Time 1 was significantly lower in those with undercorrected refractive error when compared to the control group (75 vs 92, P = .001). The median Composite score for the undercorrected refractive error group improved to 96 (P < .001) at Time 2 when compared to Time 1, while the control group remained stable at 93 (P = .417). The undercorrected refractive error group showed significantly greater improvement than the control group in 8 of 12 subscale scores and in the overall Composite score (all P values ≤ .05). A multivariate linear regression analysis, which controlled for differences in age, percent self-identified American Indian/Alaskan Native, and best-corrected visual acuity between the undercorrected refractive error and control group, showed eyeglasses to be significantly associated with improvement in NEI VFQ-25 composite score. CONCLUSION: Visual impairment from undercorrected refractive error is common in American Indian/Alaskan Natives. Providing eyeglasses results in a large, significant increase in vision-related quality of life.

The effect of visual impairment on vision-related quality of life in American Indian/Alaska Natives.

PURPOSE: To determine if National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) scores decrease with worsening visual acuity (VA) in American Indian/Alaska Natives (Al/AN), as well as determine the other associated explanatory factors for vision-related quality of life. METHODS: The study included 414 randomly selected AI/AN tribal members aged 40 years or older from the Pacific Northwest. We excluded candidates who were deceased, seriously ill, had dementia, or otherwise were unable to perform subjective testing such as visual field testing. The participants completed the NEI-VFQ-25, as well as a detailed eye examination. We defined visual impairment as presenting distance VA 20/40 or worse in the better-seeing eye. The main outcome measures were NEI-VFQ-25 composite and subscale scores. We compared median NEI-VFQ-25 composite and subscale scores in those with visual impairment to those without visual impairment. RESULTS: Visual impairment occurred in 53 (12.8%, Cl: 9.6-16.0) participants. The NEI-VFQ-25 median composite score was significantly lower in those with visual impairment as compared to those without visual impairment (77.5 vs. 90.1, p = .001). A univariate analysis showed VA to be significantly (p < .05) associated with all subscales except ocular pain. When controlling for age, gender, income level, education, percent AIAN heritage, and marital status, a multivariate proportional odds model analysis showed VA to be the best predictor of NEI-VFQ 25 composite scores. CONCLUSION: Visual impairment is common in Northwest AI/AN. The NEI-VFQ-25 was sensitive to differences in VA, suggesting it is a valid measure of vision-related quality of life in AI/AN.