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The diagram provided is of the human eye - HSC - SSCE Biology - Question 28 - 2005 - Paper 1
Question 28
The diagram provided is of the human eye. (a)(i) Identify the part of the organ labelled A. (ii) Using TWO labelled diagrams, show how the eye accommodates the foc... show full transcript
Worked Solution & Example Answer:The diagram provided is of the human eye - HSC - SSCE Biology - Question 28 - 2005 - Paper 1
Step 1
Step 2
Using TWO labelled diagrams, show how the eye accommodates the focus of near and far objects.
Answer
To show the accommodation of the eye:
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Diagram for Near Vision:
- Draw a diagram of the eye with nearby objects. Label the ciliary muscles, lens, and retina.
- Indicate that the ciliary muscles contract, allowing the lens to become thicker, which helps focus light rays from the nearby object onto the retina.
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Diagram for Far Vision:
- Draw another diagram with distant objects. Label the same structures as before.
- Show that the ciliary muscles relax, allowing the lens to become flatter, enabling the eye to focus light rays from the distant object onto the retina.
Step 3
Describe each of these conditions.
Answer
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Cataracts:
- Cataracts occur when the lens of the eye becomes cloudy, leading to blurred vision, glare, and difficulty seeing at night. This condition can be age-related or due to other factors like UV exposure, diabetes, or smoking.
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Myopia:
- Myopia, or nearsightedness, is a refractive error where distant objects appear blurry because light rays focus in front of the retina due to an elongated eyeball or steep cornea.
Step 4
Compare the technologies available to rectify these conditions.
Answer
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Cataracts Treatment:
- The most common treatment is cataract surgery, where the cloudy lens is removed and typically replaced with an artificial intraocular lens (IOL).
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Myopia Correction:
- Myopia can be corrected with glasses or contact lenses that are concave to diverge light rays, or through refractive surgery options such as LASIK, which reshapes the cornea to improve focus on the retina.
Comparison:
- While cataract surgery is a surgical intervention that effectively restores vision, myopia correction can involve non-invasive methods like glasses, or surgical options that reshape the eye's structure depending on patient suitability.
Step 5
Evaluate the benefits and limitations of BOTH technologies.
Answer
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Hearing Aids:
- Benefits: They amplify sound, provide clarity, and can enhance social interaction for those with hearing loss.
- Limitations: They do not restore hearing to normal levels, can be uncomfortable, and require regular maintenance.
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Cochlear Implants:
- Benefits: They bypass damaged parts of the ear and directly stimulate the auditory nerve, greatly improving hearing capabilities, especially in severe cases.
- Limitations: The surgery carries risks, and not everyone is a suitable candidate. Additionally, the result may vary, and some individuals may require extensive therapy post-implantation.