Which structure fills most of the eyeball, helping maintain its shape?

Which structure fills most of the eyeball, helping maintain its shape?

• A. Aqueous humor
• B. Choroid
• C. Uvea
• D. Vitreous humor

Answer: (D)

The main concept here is that the eye contains different humors that fill specific spaces. The vitreous humor fills the large posterior cavity, from the lens to the retina, and is a clear gel that gives the eyeball its shape. Its gel-like consistency supports the retina and helps keep the globe intact, so it makes up most of the eyeball’s volume. In contrast, the aqueous humor fills the small anterior segments (the front chamber and the space behind the iris) and is renewed constantly to nourish tissues and maintain pressure, not to fill the entire eyeball. The choroid and uvea are tissue layers involved in nourishment and light absorption, not filling spaces. So the substance that fills most of the eyeball and maintains its shape is the vitreous humor.

The main concept here is that the eye contains different humors that fill specific spaces. The vitreous humor fills the large posterior cavity, from the lens to the retina, and is a clear gel that gives the eyeball its shape. Its gel-like consistency supports the retina and helps keep the globe intact, so it makes up most of the eyeball’s volume. In contrast, the aqueous humor fills the small anterior segments (the front chamber and the space behind the iris) and is renewed constantly to nourish tissues and maintain pressure, not to fill the entire eyeball. The choroid and uvea are tissue layers involved in nourishment and light absorption, not filling spaces. So the substance that fills most of the eyeball and maintains its shape is the vitreous humor.