Certified Ophthalmic Assistant Practice Exam

Which layer of the eye is most important for focusing light?

1. Retina

2. Ciliary body

3. Cornea

4. Sclera

The correct answer is: Cornea

The cornea is the most important layer of the eye for focusing light because it has a significant refractive power. As the eye's primary refracting surface, it bends incoming light rays to help them converge on the retina, where visual processing begins. The curvature and transparency of the cornea play crucial roles in determining the quality of the image that is projected onto the retina. While the ciliary body is essential for adjusting the lens's shape to focus light on the retina, its primary function is to control accommodation rather than directly refracting light. The retina is responsible for receiving and processing visual information, while the sclera serves as the protective outer layer of the eyeball, providing structure rather than playing a role in light focus.