What is the primary function of the lens?

What is the primary function of the lens?

• A. Protect the retina from light
• B. Secrete aqueous humor
• C. Regulate intraocular pressure
• D. Refocus light onto the retina

Answer: (D)

The lens’s main job is to adjust the eye’s focal length so that light is sharply focused on the retina. It is a clear, flexible structure behind the iris that changes curvature to fine-tune vision. Light first hits the cornea, which provides most of the eye’s refractive power, and then the lens adds precision by changing shape during accommodation. When you look at something up close, the ciliary muscle contracts, loosening the zonular fibers and making the lens thicker and more curved, increasing its refractive power to focus near objects. When looking at distant objects, the ciliary muscle relaxes, the lens flattens, and its refractive power decreases to keep distant images sharp on the retina. The other options aren’t the lens’s role: protecting the retina from light is achieved mainly by the cornea, iris, and retina itself; secreting aqueous humor is done by the ciliary body; and regulating intraocular pressure involves production and drainage of aqueous humor, not the lens.

The lens’s main job is to adjust the eye’s focal length so that light is sharply focused on the retina. It is a clear, flexible structure behind the iris that changes curvature to fine-tune vision. Light first hits the cornea, which provides most of the eye’s refractive power, and then the lens adds precision by changing shape during accommodation. When you look at something up close, the ciliary muscle contracts, loosening the zonular fibers and making the lens thicker and more curved, increasing its refractive power to focus near objects. When looking at distant objects, the ciliary muscle relaxes, the lens flattens, and its refractive power decreases to keep distant images sharp on the retina.

The other options aren’t the lens’s role: protecting the retina from light is achieved mainly by the cornea, iris, and retina itself; secreting aqueous humor is done by the ciliary body; and regulating intraocular pressure involves production and drainage of aqueous humor, not the lens.