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 as with The Vision Charity in Sri Lanka. IRIS has also partnered with the Cambodian government program National Program for Eye Health in establishing eye clinics. Another partner is the International Centre for Eyecare Education. As of December 2008, the combined total of IRIS clinic and eye camp programs since its inception in Cambodia had resulted in 125,319 people receiving eye examinations and 23,485 surgeries being performed free of charge, 15,291 of which were to remove cataracts. In 2011, Roger Freeland Biggs was the CEO of IRIS and he was awarded an OBE "for services to Health in Asia". International