• Standardized visual acuity assessments are possible when consideration is given to legibility, acuity row legibility, letter spacing, optotype, row arrangement, and letter size gradation. The relative optotype legibilities reported by Sloan were verified experimentally under simulated conditions of optical defocus. Acuity row component letters were selected to equalize aggregate row legibilities and were arranged to minimize contaminative sequencing dependency. We describe a new acuity chart format with vertical acuity row presentations to eliminate bias from previous reading experience, and testing procedures using this chart.
Strong G, Woo GC. A Distance Visual Acuity Chart Incorporating Some New Design Features. Arch Ophthalmol. 1985;103(1):44-46. doi:10.1001/archopht.1985.01050010048016