Quiz on the Human Eye

The function of the sclera in the human eye is (a)  

• Maintaining the shape of the eye
• Focusing light onto the retina
• Regulating the amount of light ente
• Detecting color

Answer explanation

The sclera is the white outer layer of the eye that provides structure and maintains its shape. It does not focus light, regulate light entry, or detect color, making 'maintaining the shape of the eye' the correct function.

The part of the eye responsible for the refraction of light is (a)   .

• Cornea
• Iris
• Retina
• Sclera

Answer explanation

The cornea is the primary structure responsible for the refraction of light in the eye. It bends incoming light rays to help focus them onto the retina, enabling clear vision.

Match the following functions with their corresponding parts of the eye.

• Eyelid

• Maintains the shape of the eye

• Iris

• Protects the eye from dust

• Sclera

• Contains light-sensitive cells

• Retina

• Regulates the size of the pupil

Answer explanation

The main function of the retina is to contain light-sensitive cells that detect light and convert it into neural signals, which are then sent to the brain for visual processing.

What is the role of the iris in the eye?

• Regulates the amount of light entering the eye

• Focuses light onto the retina

• Maintains the shape of the eye

• Detects color

Answer explanation

The iris is responsible for regulating the amount of light that enters the eye by adjusting the size of the pupil. This function is crucial for protecting the retina and optimizing vision in varying light conditions.

Match the parts of the eye with their descriptions.

• The light-sensitive layer at the back of the eye.

• Cornea

• The transparent front part of the eye covering the iris and pupil.

• Sclera

• The colored part of the eye visible from the outside.

• Retina

• The white outer layer of the eyeball.

• Iris

Answer explanation

The iris is the colored part of the eye that is visible from the outside, surrounding the pupil. The retina is inside the eye, the sclera is the white outer layer, and the cornea is the clear front part of the eye.

The function of the yellow spot (fovea) in the eye is to (a)  

• Provides the clearest vision
• Regulates the size of the pupil
• Protects the eye from dust
• Maintains the shape of the eye

Answer explanation

The yellow spot, or fovea, is the area of the retina responsible for sharp central vision. It contains a high density of photoreceptors, allowing for the clearest vision, making it essential for activities like reading and driving.

What is the main function of the choroid in the eye?

• Prevents internal reflection

• Focuses light onto the retina

• Regulates the amount of light entering the eye

• Detects color

Answer explanation

The choroid's main function is to prevent internal reflection within the eye, ensuring that light is absorbed rather than scattered, which helps maintain clear vision.

Which structure in the eye is responsible for focusing light?

• Lens

• Iris

• Sclera

• Retina

Answer explanation

The lens is the transparent structure in the eye that focuses light onto the retina. It adjusts its shape to ensure that images are sharp, making it the primary component responsible for light focusing.

What is the function of the aqueous humor in the eye?

• Maintains the shape of the eye

• Focuses light onto the retina

• Regulates the amount of light entering the eye

• Detects color

Answer explanation

The aqueous humor is a clear fluid that fills the space between the cornea and the lens, helping to maintain the shape of the eye and providing nutrients. It does not focus light, regulate light entry, or detect color.

Match the following conditions with their causes of short sight (myopia).

• Hyperopia due to decreased lens curvature

• Lens being too thick

• Hyperopia due to shortened eyeball

• Eyeball being too short

• Myopia due to elongated eyeball

• Lens being too thin

• Myopia due to increased lens curvature

• Eyeball being too long

Answer explanation

The main cause of short sight (myopia) is the eyeball being too long, which causes light to focus in front of the retina, leading to blurred distance vision.