The basic principle for measuring the visual acuity of the eye f undus using two-beam laser interferemetry is described. The optical system of laser interference optometer is described in diagram. The results of clinical research in 90 cases having poor eyesight and special examples with ordinary disease in ophthalmology are reported. It is pointed out that the phenomenon of "flash start" is important in the measurement of visual acuity of the retina-brain system.