Measurement of indirect costs for people with vision impairment.

From a societal perspective, chronic eye diseases can affect not only the person who has vision impairment but also the economics of that society. To obtain comprehensive medical and non-medical expenditures for people with impaired vision, direct and indirect costs should be collected. Indirect costs are usually not included in cost evaluation in health economics due to the difficulty of the data collection and analysis. Questionnaires and cost diaries have been developed in this study to estimate total resource use, expenses, and lost production from the participants or their caregivers due to the participants' vision loss. Pilot testing was conducted to verify the format, clarity of instructions, relevance of content and completeness of the questionnaires and diary. Modifications were then made to the format from feedback from the participants. Diaries using large print, audio and Braille facilitate data collection for people with impaired vision.