 The technique also may be considered of inadequate scope, as it only provides an estimate of the anterior chamber angle (ACA) at the temporal limbus, in contrast with gonioscopy, which allows for a 360 degree view of the anterior chamber.Furthermore, the Van Herick technique has been found to be exceedingly sensitive to the positioning of the direct slit-lamp beam whereby a 10 degrees deviation from the perpendicular direction was found to be critical to the results and measurements.In addition, the ACA ratio was found to be highly dependent on the corneal thickness as a thin cornea would result in a larger ratio than that of a thicker cornea.