Which anatomical structure of the human eye provides the greatest portion (approximately 70% or 40-44 Diopters) of total refractive power?
Answer and explanation
Correct answer: D. Cornea
- Step 1: Total optical power of the relaxed human eye is approximately +60 Diopters. Step 2. The curved anterior air-cornea interface has a large refractive index jump (1.000 to 1.376), providing about +40 to +44 D (over two-thirds of total eye power). Answer: Cornea. Why not the others: Crystalline lens provides +15 to +20 D and adjustable accommodation; Vitreous humor provides minimal refraction; Aqueous humor maintains anterior chamber pressure.
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