Compact Refractive Error Measuring Device

In this study, a reflective aspheric optical system is used to establish an eye examination device for distance and near vision tests. The system includes a micro-display with a rotating device, an off-axis parabolic mirror, an off-axis ellipsoid mirror, a chin-fixing bracket, and vision software. The display contents of the micro-display include English C and E charts, Chinese words, graphics, and animation. The off-axis parabolic mirror and off-axis ellipsoid mirror are confocal, and the micro-display is placed at the confocal point. The micro-display is projected through an off-axis parabolic mirror for myopia's distance vision testing, and an off-axis elliptical mirror for myopia's near vision testing. Others, the graphics and animation, provide visual checks for young children. In addition, CCD cameras and AI recognition can be used as visual examinations for people with language impairment. In this study, twenty-five subjects with the refractive error were tested using E-chart and this device to obtain the decimal point VA value, and the trial frame and lens were used to obtain the diopter of glasses. The date of the experimental results was used as a reference value for ophthalmological examination. This system uses an off-axis parabolic mirror and an off-axis ellipsoidal mirror. Optical alignment is a challenge to solve for the system. Students participating in the study obtained good optics training. The advantages of the developed device include the convenience to carry with a multi-purpose and straightforward use.