Objective

To determine the relationship between visual impairment and other disabilities in a developing country.

Methods

In this cross-sectional ancillary study, all individuals 50 years and older in 18 communities in the Chitwan region of Nepal were administered visual acuity screening and the Washington Group Short Set (WGSS) of questions on disability. The WGSS elicits a 4-level response for six disability domains: vision, hearing, walking/climbing, memory/concentration, washing/dressing, and communication. The association between visual impairment and disability was assessed with age- and sex-adjusted logistic regression models.

Results

Overall, 4719 of 4726 individuals successfully completed visual acuity and disability screening. Median age of participants was 61 years (interquartile range: 55-69 years), and 2449 (51.9%) were female. Participants with vision worse than 6/60 in the better-seeing eye were significantly more likely to be classified as having a disability in vision (OR 18.4, 95% CI 9.9-33.5), walking (OR 5.3, 95% CI 2.9-9.1), washing (OR 9.4, 95% CI 4.0-21.1), and communication (OR 5.0, 95% CI 1.7-13.0), but not in hearing (OR 0.6, 95% CI 0.006-2.2) or memory (OR 2.2, 95% CI 0.7-5.1).

Conclusions

Visually impaired participants were more likely to self-report disabilities, though causality could not be ascertained. Public health programs designed to reduce visual impairment could use the WGSS to determine unintended benefits of their interventions.

Introduction

The majority of blindness worldwide could be prevented or reversed with early diagnosis and treatment, yet identifying at-risk and prevalent cases of eye disease and linking them with care remain important obstacles to addressing this burden. Leading causes of blindness like glaucoma, diabetic retinopathy and age-related macular degeneration have detectable early asymptomatic phases and can cause irreversible vision loss. Mass screening for such diseases could reduce visual impairment at the population level.

Methods and analysis

This protocol describes a parallel-group cluster-randomised trial designed to determine whether community-based screening for glaucoma, diabetic retinopathy and age-related macular degeneration reduces population-level visual impairment in Nepal. A door-to-door population census is conducted in all study communities. All adults aged ≥60 years have visual acuity tested at the census visit, and those meeting referral criteria are referred to a local eye care facility for further diagnosis and management. Communities are subsequently randomised to a community-based screening programme or to no additional intervention. The intervention consists of a single round of screening including intraocular pressure and optical coherence tomography assessment of all adults ≥60 years old with enhanced linkage to care for participants meeting referral criteria. Four years after implementation of the intervention, masked outcome assessors conduct a repeat census to collect data on the primary outcome, visual acuity. Individuals with incident visual impairment receive a comprehensive ophthalmological examination to determine the cause of visual impairment. Outcomes are compared by treatment arm according to the originally assigned intervention.

Ethics and dissemination

The trial has received ethical approval from the University of California San Francisco Institutional Review Board, Nepal Netra Jyoti Sangh and the Nepal Health Research Council. Results of this trial will be disseminated through publication in peer-reviewed journals and presentation at local and international meetings.

Trial registration number

NCT03752840.