Low level technology tool (LLT) in screening for blindness: test qualities in the outpatients department of a tertiary eye unit using the Snellen Chart

Abstract

Visual acuity is a measure of form sense which depends on the resolving power of the eye and light sense. The Snellen chart had been the universally accepted "gold standard" method used to measure visual acuity until the introduction of the crowded logMAR acuity test.Illiteracy, the cost of making the charts and the need for some basic training of the user are some of the limitations associated with the instrument when employed to screen for blindness in communities which are hard to reach. The need for a reliable, cheap, readily available and universally accepted alternative instrument for screening people with visual problems in remote places cannot be underscored especially today when there is a global fight against avoidable blindness through “Vision 2020” programmes. Locals can use this tool to identify those with visual impairment and arrange for them to be seen by the ophthalmic team for proper assessment.