You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Van Herick Test is used for: and explain in detail?
Van Herick's method Measures anterior chamber depth with a slit lamp, focus at peripheral cornea near limbus at an angle of 60 deg It Compares anterior chamber depth with corneal thickness. Van Herick's Grading Grade 4 PAC >= CT Grade 3 PAC = 1/4 to 1/2 of CT Grade 2 PAC = 1/4 of CT Grade 1 PAC < 1/4 of CT CT - Corneal thickness PAC - Peripheral anterior chamber depth Grade 4 means likelihood of angle closure is rare