This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Which component of the eye has maximum refractive index: 
Select and explain. 
A. Anterior surface of the lens, B. Posterior surface of the lens, C. Centre of the lens, D. Cornea
C: Centre of the lens
Answer: C: Centre of the lens 
Explanation: C. i.e. Centre of the lens Highest refractive index is of lens nucleus coreQ (1.406) > anterior and posterior lens coex forming anterior & posterior lens surface (1.386) > cornea (1.376) > aqueous and vitreous humor (1.336) > air (1). Gullstrand Schematic Eye Structure Surface Radius (mm) Position (mm) Thickness (mm) Refractive index Cornea Anterior 7.7 0.0 0.50 1.376 Posterior 6.8 0.50 Aqueous 3.10 1.336 Anterior lens coex Anterior 10 3.60 0.546 1.386 Posterior 7.911 Lens core (nucleus) 4.146 2.419 1.46 Posterior lens coex Anterior - 5.76 6.565 0.635 1.386 Posterior - 6.0 7.20 Vitreous 16.80 1.336 Retina -12.0 24.0