An optical apparatus applied to ophthalmology detection is disclosed. The optical apparatus includes an image capturing unit, a data comparing unit, a detection unit, a location determining unit, and a data output unit. The image capturing unit captures images of different portions of a face of a person to be tested to obtain a plurality of face images. The data comparing unit compares the plurality of face images with a built-in database. The detection unit detects on an eye of the person to be tested. The location determining unit automatically determines whether the eye detected by the detection unit is left-eye or right-eye. The data output unit selectively outputs a detection result of the detection unit, a comparing result of the data comparing unit, and/or a determining result of the location determining unit.