The feasibility of combining rapid assessment studies for measuring the progress toward Universal Eye Health.

Abstract

Dear Editor, Rapid assessment (RA) methods are the commonly used epidemiological tools to acquire data for planning and monitoring of eye care services.[1] Low-cost, rapid data collection techniques coupled with the ability to conduct using limited resources make these methods versatile. These methods are repeatable and are well poised to capture trends over time. Moreover, various RA protocols are available based on the ocular conditions and age groups.[1] The call for Universal Eye Health (UEH) coverage mandates comprehensive eye care for everyone. Therefore, a combination of these methods should be used to get an overall picture of vision impairment in a region. Combining differing different RA methods without losing the individual key advantages is recommended to document the progress toward achieving UEH in a given region. One such experiment was done in Telangana state in South India. The rapid assessment of visual impairment (RAVI) and the rapid assessment of refractive errors (RARE) were combined and implemented successfully.[2,3] The RAVI protocol was applied for the ≥40 years age group, and the RARE protocol was applied for the 16–39 years age group. Essentially, the study included all individuals in the household of age ≥15 years. As per the census data, the proportion of people in the 16–39 and ≥40 years age groups are 40% and 30%, respectively. The sample size for cross-sectional studies is typically based on the prevalence estimates from previous studies. the prevalence of visual impairment (VI) is lower in the younger age group. Therefore, an anticipated prevalence of VI in this group was considered for sample size calculation. The minimum sample size required was determined to be 4600 based on the following criteria: a conservative estimate of 4% prevalence of VI (presenting visual acuity worse than 6/12),[2] allowing for a 95% confidence interval, a precision of 20%, a design effect of 1.6 for a predetermined cluster size of 60 subjects, and 15% nonresponse rate. According to the pilot study, the cluster size of 60 could be completed in 1.5–2 days. Therefore, it was considered as the cluster size for this study. A multistage, random cluster random sampling procedure with a compact segment sampling method was used to select the participants for the study. In total, three or four clusters could be completed in a week by a team comprising one vision technician and two community eye health workers. Three such teams were involved in data collection under the direct supervision and mentorship of an optometrist. The study was completed with a good response rate, highlighting the feasibility of combining two RA studies. The advantage of combining these RAs is manifold. The same human resources can be used for data collection. There is a better response rate as all the family members in the household, except children were enrolled in the study. The family acted as a unit, and additional family-level information, such as income and assets, that are likely to influence the uptake of services could be collected. The time taken for data collection for the combined RA study was similar compared to a single RA study. The salient features of both the RA methods that are combined and used together are shown in Table 1. [Table 1] Keeping the most variables common and addition only a minimal additional variables in the >=40 year age group ensured that the training and protocol implementation in the field easier.Table 1: Highlights of the combined rapid assessment methodsRAs are meant to inform programme planning. From this point of view, data from the combined RA studies can be used in conjunction with data from school eye health programs for planning comprehensive eye care service delivery. The VI estimates, obtained from the school vision screening programs, can be used as a surrogate measure of the VI status in the school-going children (6–15 years) population, as the student enrollment rate in this region is very high. The key informant approach can be used in this region to assess vision loss in younger children (0–5 years and out of school children) and complete the data [Fig. 1].[4] Therefore, it is possible to acquire complete data on VI status in a population using various low-cost methods. Moreover, the combined raid assessments RA methods also addressed the dearth of data available in the younger age groups. These methods provide vital data on effective refractive error coverage and effective cataract surgical coverage essential for planning and monitoring UEH programs.Figure 1: Combining low-cost methods for data on visual impairment in all agesFinancial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.