1. Study of chart designs and optotypes for preschool vision screening-I. Comparability of chart designs;Sprague;J Pediatr Ophthalmol Strabismus,1989
2. Comparisons of testability of preliterate visual acuity tests in preschool children;Schmidt;Binocular Vision,1991
3. Allen figure and broken wheel visual acuity measurement in preschool children;Schmidt;J Am Optom Assoc,1992
4. Preliterate vision screening: a comparative study;Jenkins;American Orthoptic Journal,1983
5. A new picture series for preschool vision testing;Allen;Am J Ophthalmol,1957