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Abstract
Uncorrected refractive errors (URE) and presbyopia are public health challenges in community eye health today. Effective planning and management of the services to tackle these twin problems requires information for needs assessment and monitoring. Conventional cross sectional studies (population-based) which can provide this information are resource intensive and hence not repeatable. The current research was undertaken to develop a low cost rapid assessment methodology that can fill this gap.
A two stage approach was adopted. In the first stage, the RARE (Rapid Assessment of Refractive Errors) methodology was piloted and the definition for URE was validated against the standard definition for refractive errors. In the second stage, the validated methodology was used in Mahbubnagar district in Andhra Pradesh, India. The results from this study were compared with those obtained from a conventional cross sectional study conducted a decade ago. Cluster random sampling with ‘population proportionate to size (PPS)’ was employed as done in other rapid assessments. Distance visual acuity (VA) (aided, unaided and pinhole) was measured using a LogMAR Chart (English alphabet optotypes & tumbling E), near vision (unaided, aided and with age appropriate near addition) was measured with near vision chart with N notation held at 35 cm distance. Visual impairment (VI) was defined as binocular presenting VA<6/12, URE was defined as presenting VA<6/12 but improving to at least 6/12 or better on using a pinhole. Uncorrected Presbyopia was defined as binocular unaided near vision 35 years and who had no distance VI.
In the pilot study, the definition for URE based on pinhole showed good sensitivity and specificity. The main study revealed a large ‘unmet need’ for correction of uncorrected refractive errors and presbyopia. The spectacle coverage was low for both refractive errors and presbyopia. However in comparison with a cross sectional study, prevalence of URE has decreased and there was an increase in the prevalence of spectacle use.
The current research demonstrated that RARE can provide vital information for planning and management of refraction services and can assist in achieving the aim of the global initiative, VISION 2020: The Right to Sight.