This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy, Development and clinical examination, Subject name: Ophthalmology
Perimetry is a test to assess the 
Select and explain. 
A. Visual acuity, B. Intraocular pressure, C. Visual field, D. Depth of the anterior chamber
C: Visual field
Answer: C: Visual field 
Explanation: The visual field is a three-dimensional area of a subject's surroundings that can be seen at any one time around an object of fixation. The extent of the normal visual field with a 5 mm white color object is superiorly 50 degree, inferiorly 70 degree, nasally 60 degrees and temporally 90o degree. The field for blue and yellow is roughly 10 degrees less and that for red and green color is about 20 degrees less than that for white. Perimetry with a red color object is paicularly useful in the diagnosis of bitemporal hemianopia due to chiasmal compression and in the central scotoma of retrobulbar neuritis. Image : Goldmann perimetry Reference : AK KHURANA COMPREHENSIVE OPHTHALMOLOGY, Edition4, Page-481