 The test should be performed in a dim lit room with the patient directed to fixate on a distance target to minimize any fluctuations of accommodation and pupil size.The Van Herick's technique compares the depth of the peripheral anterior chamber with the cornea thickness, usually written as a fraction however, it can also be expressed as a ratio (see table 3).By grading the angle using the Van Herick technique it also allows an estimation of the probability of closure and an estimated angle in degrees (see table 2).