After an injury, one structure in a person's eye is damaged. The cornea and retina are healthy.
An eye specialist compares the injured eye with a healthy eye while the person looks at objects at two distances.
| Eye | Distance of object | Diameter of ciliary muscle ring / mm | Tension in fibres attached to the lens | Shape of lens |
|---|---|---|---|---|
| healthy | 25 cm | 8.7 | slack | thick and curved |
| healthy | 6.0 m | 10.9 | tight | thin |
| injured | 25 cm | 8.8 | slack | thick and curved |
| injured | 6.0 m | 10.8 | slack | thick and curved |
Use the results to identify the damaged structure and justify your answer.
Explain why the distant object appears blurred in the injured eye. Suggest a suitable spectacle lens and explain how it would correct the vision.
102 exam-style questions on Edexcel GCSE Biology 2.4 The eye, covering 2.4.1 Structure and function of the eye and 2.4.2 Eye defects and their correction. Each one has a worked solution and a mark scheme showing where the marks go.