Important areas of the central binocular visual field for daily functioning in the visually impaired.

PURPOSE

To determine the areas of the central binocular visual field which correspond best with self-reported vision related activity limitations (VRAL) in individuals with visual impairment using a clinically relevant and accessible technique.

METHODS

One hundred participants with mixed visual impairment undertook binocular threshold visual field testing using a Humphrey 30-2 SITA Fast program. The Activity Inventory (AI) was administered to assess overall, mobility related and reading related self-reported VRAL as part of a face-to-face clinical interview. Different eccentricities of the binocular field (central 5, 5-10, and 10-30°) were compared to self-reported VRAL in bivariate analyses and further explored using multivariate analyses.

RESULTS

All areas of the binocular visual field were significantly associated with self-reported VRAL in bivariate analyses, with greater field loss associated with increased VRAL (p < 0.001). Multivariate analyses identified that function of the central 5-10° best predicted overall self-reported VRAL, and function of the central 5° (especially the right-hand-side) and the central 10-30° (especially 10-20°) best predicted self-reported VRAL in reading and mobility tasks, respectively.

CONCLUSIONS

The results highlight the association between central binocular visual fields and self-reported VRAL in people with visual impairment. Central binocular fields can be measured using a widely available threshold test in order to understand the likely functional limitations of those with vision loss, particularly in mobility tasks. Self-reported VRAL can be estimated using the regression equations and graphs provided and difficulty levels in specific tasks can be determined.