1. 1
   An optician examines a patient's eye. Shining a bright light into the eye causes the pupil to become smaller, and the optician then asks the patient to focus first on a distant object and then on a near object, observing changes in the shape of the lens.

   (a)

   An optician examines a patient's eye and shines a bright light into it, causing the pupil to become smaller. Which structure of the eye controls the diameter of the pupil?

   [1 mark]

   • AThe cornea
   • BThe lens
   • CThe iris
   • DThe retina

   (b)

   When the patient looks at a distant object and then at a near object, the shape of the lens changes. Which structure contracts to make the lens more rounded when focusing on a near object?

   [1 mark]

   • AThe suspensory ligaments
   • BThe ciliary muscles
   • CThe optic nerve
   • DThe cornea

   (c)

   Describe the function of the cornea and the function of the retina in the eye.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A person walks from a brightly lit room into a dark cinema. After a few minutes their eyes adapt to the low light, and they can make out dim shapes around them but cannot distinguish colours clearly, even though they can see fine detail when looking directly at the screen.

   (a)

   Which retinal cells are mainly responsible for vision in dim light?

   [1 mark]

   • ARods
   • BCones
   • CFovea cells
   • DOptic nerve fibres

   (b)

   When the person looks directly at the brightly lit cinema screen, the image falls on a small region of the retina packed with cones, giving the sharpest detail. What is this region called?

   [1 mark]

   • AThe blind spot
   • BThe optic nerve
   • CThe pupil
   • DThe fovea

   (c)

   Explain why the person can see dim shapes in the dark cinema but cannot distinguish their colours clearly.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   An optician tests a patient's blind spot by covering one eye and moving an object across the patient's field of vision while the patient looks straight ahead, and separately tests the patient's pupil reflex by shining a light of varying intensity into the eye.

   (a)

   A patient has an eye test in which the optician covers one eye and asks the patient to report when a moving object, brought in from the side, first becomes visible while looking straight ahead. Explain how this test relates to the blind spot, and describe what the blind spot is.

   [3 marks]

   (b)

   Describe how the diameter of the pupil changes in response to bright light and in response to dim light, and explain how these changes are brought about by the muscles of the iris.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A student reads a book held close to their face and then looks up to focus on a distant clock on the wall, and later walks outside into bright sunlight before returning indoors to a dimly lit room.

   (a)

   Explain, in terms of the ciliary muscles, suspensory ligaments and the shape of the lens, how the eye changes focus from the near book to the distant clock (accommodation).

   [6 marks]

   (b)

   When the student walks outside into bright sunlight, their pupils rapidly become smaller, and when they return indoors to the dim room, their pupils become larger again. Explain the mechanism of this pupil reflex, including the roles of the receptors, the nervous pathway and the antagonistic muscles of the iris.

   [6 marks]

   Total for question 4: 12 marks

End of questions