Epidemiological, demographic, and economic analyses: Measurement of the value of trichiasis surgery in The Gambia

AIM: Untreated trichiasis can lead to corneal opacity. Surgery to prevent the eyelashes from rubbing against the cornea is available, but many individuals with trichiasis never undergo the operation. This study estimates the cost of illness of untreated trichiasis and the willingness to pay for surgery and compares them with the actual cost of providing surgery. MATERIALS AND METHODS: The cost of illness estimate is based on trichiasis patient demographics. Data on the implicit price of obtaining surgery and surgical utilization in a matched pair randomized trial are used to infer individual willingness to pay for trichiasis surgery. Patients in the study paid nothing out-of-pocket for surgery; the price of obtaining surgery is the value of the individual's time needed for travel and surgery plus the price of public transportation. The cost of producing surgery was calculated from project records. RESULTS: All monetary figures are reported in 1998 US dollars. The average cost of untreated trichiasis, or the net present value of lifetime lost economic productivity, was $89. Individuals facing a lower cost were more likely to undergo an operation; the inferred average willingness to pay was $1.43 (SD 0.244). Surgery cost $6.13 to provide, including $0.86 for transportation to the village. DISCUSSION: Whether the value of trichiasis surgery exceeds the cost in The Gambia depends on how the value is measured. Individuals are willing to use only limited resources to obtain surgery even though lifetime economic productivity may increase substantially. All three economic measures can be used to inform policy.