This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Squint, Subject name: Ophthalmology
Hirschberg test measures: 
Select and explain. 
A. Cataract, B. Strabismus, C. Refractive error, D. Glaucoma
B: Strabismus
Answer: B: Strabismus 
Explanation: Hirschberg test (for Tropias or manifest squint) Flash a torch at the forehead (Glabella) of patient, ask the patient to look at the light Ohophoric- Reflection of light is exactly at the center of the pupil Heterophoric- Reflection of light is not at the center of the pupil