Which of the following correctly lists the structures in order as light passes through the eyeball?

• A. Aqueous humor → Cornea → Lens → Retina → Vitreous humor
• B. Retina → Vitreous humor → Lens → Cornea → Aqueous humor
• C. Lens → Cornea → Vitreous humor → Retina → Aqueous humor
• D. Cornea → Aqueous humor → Lens → Vitreous humor → Retina

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the anatomy of the eye and the path light takes as it enters and travels through the structures of the eyeball. Light must pass through several transparent structures before reaching the retina, where it is detected and processed.
2. Step 2: Identify the first structure light encounters. The cornea is the outermost transparent layer of the eye and is responsible for refracting (bending) light to help focus it. Therefore, light first passes through the cornea.
3. Step 3: After the cornea, light enters the aqueous humor, a clear fluid located in the anterior chamber of the eye. The aqueous humor helps maintain intraocular pressure and provides nutrients to the cornea and lens.
4. Step 4: Next, light passes through the lens, a flexible, transparent structure that further focuses the light onto the retina. The lens adjusts its shape to focus on objects at varying distances.
5. Step 5: After the lens, light travels through the vitreous humor, a gel-like substance that fills the main cavity of the eyeball and helps maintain its shape. Finally, light reaches the retina, the innermost layer of the eye, where photoreceptor cells (rods and cones) detect the light and convert it into neural signals for the brain to interpret.