This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Optics and refraction, Subject name: Ophthalmology
[{'content': 'Which of the following laser is used in LASIK \nSelect and explain. \nA. Excimer, B. Nd-Yag, C. Argon, D. Krypton', 'role': 'user'}, {'content': 'Answer: A \nExplanation: LASIK : In this technique first a flap of 130-160 micron thickness of anterior corneal tissue is raised with the help of an automated microkeratome. Recently, femtosecond laser is being used for more accurate and smooth flaps. After creating a corneal flap midstromal tissue is ablated directly with an Excimer Laser beam, ultimately flattening the cornea. Reference: A.K.Khurana; 6th edition ; Page no: 53', 'role': 'assistant'}]