The Functional Vision Score-A New Method to Assess Visual Function.

PURPOSE: To design and investigate a functional vision test to evaluate visual functioning in a wide range of daily activities.

METHODS

Sixty participants were included and divided into 4 groups of 15 each, according to the BCVA in their better eye: 20/20 to 20/25 (Group 1), 20/32 to 20/64 (Group 2), 20/100 to 20/200 (Group 3), and lower than 20/400 (Group 4). A 10-item test simulating activities of daily life was designed for the study, to evaluate patients' functional vision. Tasks were evaluated for successful completion and timed. For each task, the time to completion was divided by the mean of Group 1 participants, and the resulting ratio was scored. The total scores of all 10 tasks were termed the Functional Vision Score (FVS).

RESULTS

The mean FVS was 12.5 ± 5.3, 21.8 ± 5.8, 35.0 ± 15.0, and 48.3 ± 15.2 in Groups 1-4, respectively (p < 0.001), with a significant correlation between participants' FVS and the BCVA in their better eye (R = 0.79, p > 0.001). On average, compared to Group 1, mean times of task completion were 1.5-2 times longer in Group 2, 2-4 times longer in Group 3, and 4-6 times longer in Group 4.

CONCLUSIONS

The FVS is simple to perform and assesses vision-related functionality, enabling a more comprehensive evaluation of visual function. It considers motor and cognitive abilities and not only visual acuity. It may serve clinicians and patients, as well as official agencies, who need a tool to determine functional vision.