The economics of vision impairment and its leading causes: A systematic review

Author: Marques AP, Ramke J, Cairns J, Butt T, Zhang JH, Jones I, Jovic M, Nandakumar A, Faal H, Taylor H, Bastawrous A, Braithwaite T, Resnikoff S, Khaw PT, Bourne R, Gordon I, Frick K, Burton MJ.

Geographical coverage: Western Europe and North America

Sector: Economic evaluation

Sub-sector: Cost

Equity focus: Not reported

Study population: Patients with vision impairment

Review type: Economics review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background

Vision impairment (VI) affects a significant and growing global population, with an estimated 1.1 billion individuals affected in 2020, projected to rise to 1.8 billion by 2050—mostly in low- and middle-income countries (LMICs). In 2020, the global economic productivity loss due to VI was estimated at $411 billion. The increasing demand for eye care services, driven by ageing populations, places added pressure on healthcare systems.

Objectives

To describe and summarise the costs associated with vision impairment (VI) and its leading causes, and to provide insights into the economic burden of VI. This includes evaluating the impact of emerging treatments and technological advancements in eye care on healthcare systems and broader societal costs.

Main findings

The review emphasised the substantial economic burden of vision impairment and its main causes, underlining the importance of standardised methodologies and improved research coverage in underrepresented regions.

Out of 2,733 articles screened, plus 14 additional records identified through expert input, 138 studies met the eligibility criteria and were included in the review.

Fourteen studies (10%) reported global data. Two-thirds (96/147; 65%) of all cost estimates originated from high-income countries. Western Europe contributed the highest number of regional estimates (43/155; 28%), followed by North America (35/155; 23%). No cost estimates were found for eight of the 21 global regions, including Central Asia, Eastern Europe, Southern Latin America, the Caribbean, Andean Latin America, Oceania, Central sub-Saharan Africa, and Southern sub-Saharan Africa.

The 138 studies provided 202 cost estimates, categorised into four components: direct costs, productivity losses, informal care costs, and intangible costs. Direct costs were the most frequently reported.

Treatment costs varied widely across regions and conditions. For example, cataract surgery ranged from $54 in Nigeria to $3,654 in Japan. The cost of spectacles for refractive error correction ranged from $12 in India to $201 in Europe. Anti-VEGF treatment for age-related macular degeneration (AMD) had the highest variability, from $3,354 in South Korea to $62,985 in the United States.

Methodology

A systematic search was conducted in Medline (16 November 2019) and the Centre for Reviews and Dissemination (CRD) database (12 December 2019) to identify studies reporting on the costs of vision impairment and its major causes. The CRD includes the NHS Economic Evaluation Database (NHS EED), the Database of Abstracts of Reviews of Effects (DARE), and the Health Technology Assessment (HTA) database. The search was restricted to studies published between 1 January 2000 and the search date, with no limits applied to language or geographic region.

Reference lists of all included studies were screened for additional publications. Experts in health economics and eye care were contacted to identify further studies and grey literature. Two reviewers independently screened titles, abstracts, and full texts for inclusion. Disagreements were resolved via discussion or a third reviewer.

One reviewer extracted data, and a second reviewer verified the extracted information. Two reviewers independently assessed study quality using the British Medical Journal (BMJ) checklist for economic evaluations, adapted for cost-of-illness studies. A narrative synthesis approach was used to present the findings.

Applicability / External validity

The review found that two-thirds of cost data were derived from high-income countries, despite 90% of people with vision impairment residing in low- and middle-income countries (LMICs). There is a clear need for more robust economic research in LMICs to accurately quantify the burden and inform policy decisions.

Geographic focus

While the review applied no geographical restrictions, cost estimates were absent for eight global regions, limiting global representativeness.

Summary of quality assessment

Overall, there is medium confidence in the conclusions. The review did not analyse or report findings according to the risk of bias of the included studies, which limits the reliability of its results.