The LEA TEST VISION SYSTEM includes the LEA SYMBOLS® and LEA NUMBERS®, and is the only complete vision testing system to use the same optotype across all testing situations. Dr. Hyvärinen's core tests are for screening and testing situations involving all children and can be used for conducting functional vision assessments in children and adults with developmental delays and disabilities. Dr. Hyvärinen's core tests assess near and distance visual acuity, contrast sensitivity, visual field deficits, cognitive vision, visual adaptation, and color vision. The American Academy of Pediatrics includes LEA SYMBOLS on its list of recommended tests for screening the vision of preschoolers.