This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Optics and Errors of Refraction, Subject name: Ophthalmology
[{'content': 'Refraction of eye is affected by all except: \nSelect and explain. \nA. Removal of vitreous, B. Lens thickened, C. Optic atrophy, D. Axial length changed', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Optic atrophy does not have any effect on the refractive status of eye. Most Impoant factor is axial length (Q) for myopia* Other impoant factors that determine the refractive power Keratometry means curvature of cornea Lens- thickness , position and sclerosis as the lens has highest refractive index* Remember 1 D change in axial length cause almost 2.5 D change in refractive error* 1 D change in corneal curvature cause 6 D change in refractive error*', 'role': 'assistant'}]