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
[{'content': 'Field defect in open angle glaucoma is best detected by? \nSelect and explain. \nA. Humphrey field perimeter, B. Goldman perimeter, C. Listers perimeter, D. Bjerrum screen', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Diagnosis of glaucoma field defect is best done by Humphrey field perimeter(Gold standard). EARLIEST VISUAL FEILD DEFECT- PARA CENTRAL SCOTOMA Visual feild is defined as area if space visible to human eye without moving the eye fro central target. Rule of thumb:Earliest visual field defect in glaucoma always begin from close to center i.e Paracentral > Bjerrum > Generalized constriction. Extra edge: In Glaucoma, Temporal visual field is the last visual field to be affected.', 'role': 'assistant'}]