First of all, the anterior chamber is a space enclosed by the cornea of the eye, the angle of the atrium and the surface of the iris, and the pupil together. The depth of the anterior chamber is mainly the vertical distance from the inner surface of the cornea to the outer surface of the iris and the pupil. Therefore, the anterior chamber depth examination is mainly to see or measure the distance from the inner surface of the cornea to the outer surface of the iris and the pupil, which is divided into peripheral anterior chamber depth and central anterior chamber depth. The main methods of examination are slit lamp examination and anterior segment OCT, type A / B ultrasonography, the former mainly relies on the subjective judgment of the doctor, the latter two are relatively objective, especially OCT examination is more accurate.