An instrument is used while a person tries to focus on a label held 20 cm from the eye. The instrument calculates the distance from the front of the cornea at which the light rays would meet.
| Measurement | Distance from the front of the cornea in mm |
|---|---|
| position of the retina | 23.5 |
| position where the light rays would meet | 25.0 |
Explain what the measurements show about the person's vision and how a spectacle lens could correct the defect.
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.