The Van Herick technique for grading the depth of anterior chamber angles is one of the easiest methods to estimate the “openness” of the angle.
With an optic section of the limbal cornea, orient your beam at about a 60 degree angle and compare the width of the corneal section and the width of the shadow adjacent to it.
1:1 – Open angle, VH grade 4
1:1/2 – Open angle, VH grade 3
1:1/4 – Narrow angle, VH grade 2 (Angle Closure Possible)
1: <1/4 – Angle closure likely, VH grade 1