Sight: แบบฝึกหัด

When light from an object falls on the blind spot of the human eye, why are we unable to perceive that object?

When light enters the eye and forms an image on the retina, what is the nature of this image?

During an ox eye dissection, a student finds a region where the optic nerve exits the eyeball. If a small image was focused exactly on this region, what would happen and why?

What is the main function of the pupil in the human eye?

When observing a garden in dim moonlight, a person may be able to see the shapes of objects but will find it difficult to distinguish their colours. Which of the following best explains this?

Why is it dangerous to look directly at the Sun with the naked eye?

The image formed on the retina of a healthy human eye is inverted. Briefly explain why we still perceive the world as being upright.

A person is diagnosed with hyperopia (long-sightedness).

a) Explain how the eye of a person with hyperopia typically focuses light rays from a nearby object relative to the retina, causing blurred vision.

b) What type of lens is used to correct hyperopia, and how does it help the eye focus light correctly?

The human eye is a delicate organ, and practicing good eye habits is essential for maintaining clear vision and preventing strain.

a) Explain why reading in dim light is considered a poor habit for eye health. (1 point)

b) Health experts often recommend that after using a computer for a long time, we should look at distant objects or green plants. Explain how looking at a distant object helps to reduce eye fatigue. (2 points)

The eye adjusts its lens shape to ensure that light rays focus perfectly on the retina.
a) When an individual shifts their focus from a distant mountain to a near map, describe the resulting change in the thickness of the lens. (1 point)
b) Name the muscles that control this change in lens shape and describe their state (relaxed or contracted) when looking at the near map. (2 points)
c) Explain why this adjustment is necessary for the light rays to form a sharp image on the retina. (2 points)