The human eye functions like a camera, using a refracting system with a lens to focus light onto the retina, where the image is formed. The iris controls the amount of light entering through the pupil, while the lens adjusts its curvature to focus on objects at various distances through a process called accommodation. In young individuals, accommodation is highly flexible, but it diminishes with age, leading to vision defects. The near point is the closest distance at which the eye can focus clearly, while the far point is the maximum distance at which it can focus. Vision problems can often be corrected using glasses or contact lenses.
What part of the eye functions like the film in a camera?
The retina functions like the film in a camera, recording the image formed by the lens.
How does the eye focus on objects at different distances?
The eye focuses on objects at various distances by adjusting the curvature of the lens, a process called accommodation, controlled by the ciliary muscles.
What is the role of the iris in the human eye?
The iris controls the amount of light entering the eye by adjusting the size of the pupil.
What happens to the pupil size in bright light?
In bright light, the iris contracts, reducing the size of the pupil to limit the amount of light entering the eye.
What is accommodation in the human eye?
Accommodation is the process by which the eye adjusts the curvature and focal length of the lens to focus on objects at different distances.
What controls the amount of light entering the human eye?
a) Pupil
b) Lens
c) Retina
d) Iris
Answer: d) Iris
What is the process of adjusting the eye's focus for objects at different distances called?
a) Convergence
b) Refraction
c) Accommodation
d) Diffraction
Answer: c) Accommodation
When an object is far away, what happens to the ciliary muscles?
a) They contract
b) They relax
c) They have no effect
d) They distort the lens
Answer: b) They relax
What happens to the pupil in dim light?
a) It contracts
b) It dilates
c) It remains the same
d) It disappears
Answer: b) It dilates
What is the near point of the eye?
a) The furthest distance an object can be seen
b) The closest distance an object can be seen clearly
c) The point where the image is focused
d) The distance at which light is refracted
Answer: b) The closest distance an object can be seen clearly