What part of the eye is described as the window through which light enters?

• A. Retina
• B. Lens
• C. Cornea
• D. Iris

Answer: (C)

Light entering the eye is first passed through the cornea, the clear, curved front surface. Its transparency and shape make it the eye’s initial window, bending most of the light that will be focused onto the retina. In fact, the cornea provides the majority of the eye’s refractive power, beginning the focusing process as soon as light hits the eye. The lens then fine-tunes the focus, while the iris regulates how much light can enter. If the cornea becomes cloudy or scarred, vision is blocked or blurred because light can’t pass through properly. The retina sits at the back of the eye and detects the light to create vision, but it is the cornea that marks the entry point and primes the optical image.