A person with short-sightedness wears concave contact lenses. The person then has laser eye surgery and can see distant objects clearly without the contact lenses. On one occasion, the person puts the old contact lenses back in.
Explain how the laser surgery corrected the short-sightedness and why wearing the old contact lenses would make distant objects appear blurred.
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.