This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glaucoma, Subject name: Ophthalmology
Earliest field defect in open angle glaucoma is - 
Select and explain. 
A. Contraction of the all isopters, B. Enlarged blind spot, C. Nasal tip, D. Arcuate scotoma
A: Contraction of the all isopters
Answer: A: Contraction of the all isopters 
Explanation: Field defect in the order of appearance Isopter contractionBaring of blind spotsmall wing shaped paracentral scotomasiedel's scotomaArcuate or Bjerrum's scotomaRing or double arcuate scotomaRoenne's central nasal stepperipheral field defectsAdvanced glaucomatous field defects. Ref :Ophthalmology A K Khurana 6th edition chapter-10 page no :233