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Figure 14 shows a cross-section of a human eye - Edexcel - GCSE Biology - Question 7 - 2022 - Paper 1
Question 7
Figure 14 shows a cross-section of a human eye. (a) Cataracts can develop in the eye causing people to have blurred vision. (i) Which structure of the eye can deve... show full transcript
Worked Solution & Example Answer:Figure 14 shows a cross-section of a human eye - Edexcel - GCSE Biology - Question 7 - 2022 - Paper 1
Step 1
Step 2
Describe how cataracts are corrected by surgery.
Answer
Cataracts are corrected through a surgical procedure known as cataract surgery. This involves removing the cloudy lens and replacing it with an artificial intraocular lens (IOL). The operation usually restores clear vision, allowing light to properly focus on the retina.
Step 3
Explain how the size of the pupil of the eye changes when a torch is shone into the eye of a person.
Answer
When a torch is shone into the eye, the bright light triggers the pupillary light reflex, causing the pupil to constrict. This adjustment reduces the amount of light entering the eye, protecting the retina from excessive brightness and helping to improve focus.
Step 4
Explain why this person cannot see distant objects clearly and how the problem can be corrected.
Answer
The person likely suffers from hyperopia (farsightedness), where the light rays from distant objects focus behind the retina. This results in blurry vision for distant objects. To correct this issue, convex lenses in glasses or contact lenses can be prescribed. These lenses converge light rays before they enter the eye, helping to focus them directly on the retina for clearer vision.