Visual acuity, contrast sensitivity, colour vision

Question 1

Indications for pinhole:

Answer 1

• Recent onset reduced vision
• Unilateral reduced vision
• Sudden onset reduced vision

Question 2

Symptoms of neurological disease:

Answer 2

• Sudden onset reduced vision
• Reduced vision affecting one eye only
• Headaches
•Changes in the appearance of colours
• Ocular pain- worse on eye movement
• Changes in pupil size

Question 3

Investigations for neurological disease:

Answer 3

1. Visual Acuity (Monocular and Binocular)
2. Contrast Sensitivity (Monocular and Binocular)
3. Colour vision (Monocular)
4. Pupil responses
5. Ocular Motility
6. Visual field assessment (Monocular)
7. Indirect Ophthalmoscopy

Question 4

Congenital colour vision deficiency:

Answer 4

• Genetic- inherited from parents
• Males 8%, females <1%
• Often asymptomatic
• Bilateral, equal
• Not progressive
•No treatment

• Usually red-green deficit

Question 5

Acquired Colour Vision Deficiency

Answer 5

• Sign of ocular disease
• May be unilateral, often asymmetrical
• Test Monocularly
• May be symptomatic
• Progressive

•Blue-Yellow

Question 6

Example of acquired vision deficiency:

Answer 6

• Age related cataract
- Yellowing of the lens
- Yellow filter - reduced sensitivity to blue

• Glaucoma (primary open angle)
- Loss of retinal ganglion cells
- development of blind spots
- reduced sensitivity to blue

Question 7

Ishihara test:

Answer 7

• Red-Green deficiencies only
• Highly sensitive
• Numbers made-up of small dots
• Dot colours are confused by patients with colour vision deficiency

Question 8

City university colour vision test

Answer 8

• Red-Green and Blue-Yellow deficiencies
• Which dot is closest in colour to the central dot?
Each of the four dots picked by:
1. Normal colour vision
2. Reduced sensitivity to red
3. Reduced sensitivity to green
4. Reduced sensitivity to blue

Question 9

Indications for colour vision tests:

Answer 9

• New child patient (<16 years old)
• Request for occupational purposes

• Symptoms of changes to colour vision
• Symptoms of neurological disease

• Sudden onset reduced vision
•Reduced vision affecting one eye only
• Headaches
•Changes in the appearance of colours
• Ocular pain- worse on eye movement
• Changes in pupil size