What is the primary function of the cornea in the visual system?

What is the primary function of the cornea in the visual system?

• A. Refracts and focuses incoming light; provides most of the eye’s optical power.
• B. Produces Tears to Lubricate the Eye.
• C. Controls Pupil Size.
• D. Provides Blood Supply to the Cornea.

Answer: (A)

The cornea’s main job is to bend (refract) light as it enters the eye and help focus images on the retina. Its front surface is highly curved and has a large refractive index difference between air and corneal tissue, which together give the eye about 40 diopters of optical power—the majority of the eye’s total focusing power (with the lens contributing the rest and providing accommodation). Tears lubricate and nourish the surface, but they don’t define the cornea’s primary role. The pupil is controlled by the iris, not the cornea, and the cornea itself is avascular, meaning it does not supply blood to itself—nutrients come from surrounding fluids and the tear film.

The cornea’s main job is to bend (refract) light as it enters the eye and help focus images on the retina. Its front surface is highly curved and has a large refractive index difference between air and corneal tissue, which together give the eye about 40 diopters of optical power—the majority of the eye’s total focusing power (with the lens contributing the rest and providing accommodation). Tears lubricate and nourish the surface, but they don’t define the cornea’s primary role. The pupil is controlled by the iris, not the cornea, and the cornea itself is avascular, meaning it does not supply blood to itself—nutrients come from surrounding fluids and the tear film.