Visual impairment as a function of visual acuity in both eyes and its impact on patient reported preferences.

PURPOSE: To assess the impact of VA loss on patient reported utilities taking both eyes into account compared to taking only the better or the worse eye into account. METHODS: In this cross-sectional study 1085 patients and 254 controls rated preferences with the generic health-related (EQ-5D; n = 868) and vision-specific (Vision and Quality of Life Index (VisQoL); n = 837) multi-attribute utility instruments (MAUIs). Utilities were calculated for three levels of VA in the better and worse eyes, as well as for 6 different vision states based on combinations of the better and worse eye VA. RESULTS: Using the VisQoL, utility scores decreased significantly with deteriorating vision in both the better and worse eyes when analysed separately. When stratified by the 6 vision states, VisQoL utilities decreased as VA declined in the worse eye despite stable VA in the better eye. Differences in VisQoL scores were statistically significant for cases where the better eye had no vision impairment and the worse seeing fellow eye had mild, moderate or severe vision impairment. In contrast, the EQ-5D failed to capture changes in better or worse eye VA, or any of the six vision states. CONCLUSIONS: Calculating utilities based only on better eye VA or using a generic MAUI is likely to underestimate the impact of vision impairment, particularly when the better eye has no or little VA loss and the worse eye is moderately to severely visually impaired. These findings have considerable implications for the assessment of overall visual impairment as well as economic evaluations within eye health

Utility across all six vision states (VS), for the VisQoL and the EQ-5D utility instruments, demonstrating a reduction of visual acuity with worsening vision states for the VisQoL but not the EQ-5D.

<p>Utility across all six vision states (VS), for the VisQoL and the EQ-5D utility instruments, demonstrating a reduction of visual acuity with worsening vision states for the VisQoL but not the EQ-5D.</p

Characteristics of the sample.

<p>AMD = age-related macular degeneration; DR = diabetic retinopathy; DME = diabetic macular oedema; VA = visual acuity; VisQoL = Vision and Quality of Life Index; EQ-5D = Euro Quality of Life Questionnaire; LogMAR = logarithm of the minimum angle of resolution.*data incomplete.</p

VisQoL utility scores by better or worse eye category and per vision state (by VA category).

<p>VA = visual acuity, VisQoL = Vision and Quality of Life Index, *indicates significant difference (p≤0.001) between categories using post-hoc Bonferroni testing following ANCOVA. Bolded data correspond to the 6 vision states relating to combined categories of VI in the better and worse seeing eyes.</p