Night myopia at night automobile luminances: final report.

One-hundred seventy-five persons viewed test letters of 35 and 11% contrast at 0.1 and 0.01 fL chart luminance while lenses (+0.25 to -1.50 D in 0.25-D steps) were placed before their eyes (and glasses, if they wore them). With one or more of the minus lenses, only 9% of the subjects obtained improved acuity by one or more lines on the chart. The most common optimum lens power was -0.75 D.