Abstract

AIM To ascertain utility values associated with varying degrees of legal blindness.

METHODS A cross sectional study on three group of patients. There were: (1) 15 patients with complete absence of vision (no light perception) in at least one eye who were asked to assume a scenario of no light perception in the second eye as well, (2) 17 patients with light perception to counting fingers in the better seeing eye, and (3) 33 patients with 20/200–20/400 vision in the better seeing eye. Utility values were measured using the time trade-off and standard gamble methods in each of the three groups.

RESULTS The mean time trade-off utility value for the no light perception group with the theoretical scenario of bilateral absence of light perception was 0.26 (95% CI, 0.19–0.33). The mean utility value for the light perception to counting fingers group was 0.47 (95% CI, 0.33–0.61), and the mean utility value for the 20/200–20/400 group was 0.65 (95% CI, 0.58–0.72). Thus, patients with no light perception in one eye, who were presented with the same scenario in the second eye as well, were willing to trade almost 3 out of every 4 years of remaining life in return for perfect vision in each eye. Those with light perception to counting fingers would trade approximately 1 of 2 remaining years and those with 20/200–20/400 would trade approximately 1 of 3 remaining years.

CONCLUSIONS There is a wide range of utility values associated with legal blindness. The utility value decreases dramatically with perceived total loss of vision (absence of light perception in each eye), compared with counting fingers to light perception vision, indicating that the preservation of even small amounts of vision in patients with legal blindness is critically important to their wellbeing and functioning in life.