Abstract
Purpose: :
We previously developed the Amblyopia and Strabismus Questionnaire (A&SQ) to measure the quality of life of amblyopia and/or strabismus with a disease specific questionnaire. A large historic cohort that had been treated for amblyopia 35 years ago and had filled out the A&SQ (N=174) has been orthoptically re–examined for the clinical validation of the A&SQ. To estimate the absolute measure of quality of life in amblyopia and strabismus patients, utility analysis was performed in the historic cohort
Methods: :
Subjects of the historic cohort were first asked which eye condition troubled the most: the amblyopic eye, the squinting eye, or the lack of depth vision. Then Standard Gamble (SG) and Time Tradeoff (TTO) forced choices were presented to the subjects of the historic cohort. The TTO and SG outcomes were converted into utility values by subtracting the obtained value from 1.0 (perfect vision and not prepared to give up any time or take any risk). Then the utility values were correlated by multivariate regression analysis to the reassessed orthoptic parameters of visual acuity, angle of strabismus and binocularity per subjects.
Results: :
Most subjects of the historic cohort were most troubled by the amblyopic eye, less with the lack of depth vision and least subjects with the squinting eye. An occasional subject was more troubled by glasses or lenses and itching eyes. Using the SG, a half of the cohort was not willing to take any death risk for relieve of the amblyopic eye, the remaining half accepted a risk of approx. 1 in 10.000, although occasionally subjects accepted a risk of 1 in 50. Similar results were obtained for the lack of depth vision. Almost all subjects of the cohort were willing to sacrifice various periods of life, varying from 1 day to 6 years. Interestingly, subjects who expected to have a long life were willing to sacrifice longer periods of life.
Conclusions: :
Although the SG yielded low values (risk of approx. 1 in 10.000), the total burden is considerable since approx. 1 % of the population has an insufficiently treated amblyopia.
Keywords: amblyopia • strabismus • quality of life