Abstract: Objective To compare the vision objectively assessed by SPVERA with the illiterate E Acuity in normal subjects. Methods The effect of artificially induced image defocusing on visual acuities (Vas) measured by SPVEP and illiterate E chart measurement was studied in 14 normal subjects. SPVEP was recorded using vertical gratings of 8 different spatial frequencies ranging from 0.235 9 to 30.203 2 c/deg. The responses were averaged and displayed through the discrete Fourier transform on the monitor display. SPVERA was determined by extrapolating the PVER amplitude-spatial frequency function to baseline. SPVERA was compared with illiterate E visual acuity measured under the same conditions of optical defocus. Results With moderate defocusing(<+1.0 diopter(D),VA>0.42), the SPVERA were equal to or poorer than the illiterate E visual acuity. With more defocus (>+2.0 diopter (D),VA<0.3),the SPVERA became better than the illiterate E chart Visual Acuity. The correlation between the two acuities was r2=0.919. Conclusion SPVERA and the illiterate E visual acuity correlated to a certain degree. We conclude that the SPVERA is effective in estimating vision objectively.

Key words: SPVERA, vision, defocus