Eye chart smaller symbols until the person cannot identify the symbols. The smallest symbols that can be reliably identified is considered the person's visual acuity. The Snellen chart is the most widely used. Alternative types of eye charts include the logMAR chart, Landolt C, E chart, Lea test, Golovin–Sivtsev table, the Rosenbaum chart, and the Jaeger chart. Charts display several rows of optotypes, which are standardized symbols for testing vision. Optotypes are usually letters, numbers, or geometric symbols. Each row of the chart depicts optotypes of a different size. Typically the largest optotypes are in the top row. The optotypes become progressively
International Resources for the Improvement of Sight International Resources for the Improvement of Sight International Resources for the Improvement of Sight (IRIS) is an International NGO that specializes in prevention of blindness and restoration of sight. It was founded in 1996 by Michele Claudel and John Stewart. It was initially founded to help people in Cambodia without access to eye care, it has since expanded to Nepal, Lao PDR and Sri Lanka. IRIS equips new eye clinics, strengthens existing ones, conducts eye screening, provides cataract surgery for poor people, primary eye care training for staff. IRIS has partnered with other NGOs to provide funding for services, such