AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
To focus on a distant object: • the ciliary muscles relax • the suspensory…
Full specification wording
The eye (biology only): To focus on a distant object: • the ciliary muscles relax • the suspensory ligaments are pulled tight • the lens is then pulled thin and only slightly refracts light rays.
When you look at a distant object, light rays arrive nearly parallel and need less refraction to focus on the retina.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 6 of 10
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
When you look at a distant object, light rays arrive nearly parallel and need less refraction to focus on the retina. The ciliary muscles relax, which increases tension in the suspensory ligaments so they are pulled tight. This tension pulls the elastic lens thin and flatter, reducing its refractive power. The lens then refracts light rays only slightly, allowing the nearly parallel rays to converge on the retina. The sequence is: ciliary muscles relax, suspensory ligaments tighten, lens is pulled thin, light is refracted slightly, and a clear image forms on the retina. This is the resting state of the eye for distant vision and is part of accommodation.
What earns the marks
- The ciliary muscles relax when focusing on a distant object.
- Relaxation of the ciliary muscles increases tension in the suspensory ligaments, so they are pulled tight.
- The lens is pulled thin and flatter because the suspensory ligaments are tight.
- A thinner lens refracts light rays only slightly.
- Slight refraction is sufficient to focus nearly parallel rays from a distant object on the retina.
Common mistakes and how to put them right
Saying the suspensory ligaments relax for distant vision.
Put it right by linking ciliary muscle relaxation to increased ligament tension.
Stating the lens becomes thicker for distant objects.
Put it right by associating distant vision with a flatter lens and slight refraction.
Thinking the ciliary muscles contract for distant vision.
Put it right by associating relaxation with a thin lens.
Exam tips
- Learn the distant-focus sequence as a chain: relax, tighten, thin, refract slightly.
- Contrast near and distant focusing in a table to avoid reversing the muscle and ligament states.
- Use the phrase 'refracts light rays only slightly' rather than 'does not refract light' because the lens still refracts some light.
Try the lesson
The start of the The eye (biology only): To focus on a distant object: • the ciliary muscles relax • the suspensory ligaments are pulled tight • the lens is then pulled thin and only slightly refracts light rays. lesson, made from checked teaching notes for this specification point.
Have a go first
Which sequence of events occurs when the eye focuses on a distant object?
Listen
When you look at a distant object, light rays arrive nearly parallel and need less refraction to focus on the retina. The ciliary muscles relax, which increases tension in the suspensory ligaments so they are pulled tight. This tension pulls the elastic lens thin and flatter, reducing its refractive power. The lens then refracts light rays only slightly, allowing the nearly parallel rays to converge on the retina. The sequence is: ciliary muscles relax, suspensory ligaments tighten, lens is pulled thin, light is refracted slightly, and a clear image forms on the retina. This is the resting state of the eye for distant vision and is part of accommodation. A strong answer earns marks for these points. The ciliary muscles relax when focusing on a distant object. Relaxation of the ciliary muscles increases tension in the suspensory ligaments, so they are pulled tight. The lens is pulled thin and flatter because the suspensory ligaments are tight. A thinner lens refracts light rays only slightly. A common slip: Saying the suspensory ligaments relax for distant vision: they are pulled tight. Instead, linking ciliary muscle relaxation to increased ligament tension. Exam tip: Learn the distant-focus sequence as a chain: relax, tighten, thin, refract slightly.
See it
Put it in order
Put these steps in the order they happen.
- 1. Suspensory ligaments pulled tight
- 2. Ciliary muscles relax
- 3. Focus on a distant object
- 4. Clear image forms on the retina
- 5. Lens refracts light rays only slightly
- 6. Lens pulled thin
Key words
Say what each word means before you turn the card.
Ciliary muscles
Try answering aloud or in your head before turning the card.
Suspensory ligaments
Try answering aloud or in your head before turning the card.
Lens
Try answering aloud or in your head before turning the card.
Accommodation
Try answering aloud or in your head before turning the card.
See every definition
- Ciliary muscles
- These relax when focusing on a distant object, which increases tension in the suspensory ligaments.
- Suspensory ligaments
- These are pulled tight when focusing on a distant object because the ciliary muscles relax.
- Lens
- This is pulled thin and flatter when the suspensory ligaments are tight, so it refracts light rays only slightly.
- Accommodation
- Focusing on a distant object, where the lens is pulled thin and light is refracted slightly, is part of this.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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