This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Von Herick angle grade '3' of anterior chamber denotes? 
Select and explain. 
A. Wide open angle, B. Moderately open angle, C. Moderately narrow angle, D. Closed angle
B: Moderately open angle
Answer: B: Moderately open angle 
Explanation: Ans. is 'b' i.e., Moderately open ang Classification of anterior chamber angle based on van herick angleof the anterior chamber estimation method Angle grade Angle grade Cornea to angle ratio 4 Wide open angle incapabel of closure. Iris to cornea angular separation equals to 35-45 Anterior chamber depth (shadow) is equal to or greater than corneal thickness 3 Moderately open angle incapable of closure. Iris to corneal angular separation equals to 20-35deg Anterior chamber depth (shadow) is between 1/4 and 1/2 of the corneal thickness 2 Moderately narrow angle closure possible. Iris to corneal angular separation equals to 20deg Anterior chamber depth (shadow) is equal to 1/4 of the corneal thickness 1 Extremely narrow angle, closure chance high. Iris to corneal angular separation equals to 10deg Anterior chamber depth (shadow) is equal to less than 1/4 of the corneal thickness 0 Basically closed angle. Iris to corneal angular separation is 0 Anterior chamber depth (shadow) is nil or only a very narrow slit