3. Acquired defects

Question 1

1. What is the prevalence of acquired defects in males and females?
2. When are acquired defects onset?
3. Are acquired defects easy to classify?
4. Are both eyes affected equally in acquired defects?
5. Is VA and visual fields affected in acquired defects?

Answer 1

1. Equal in males and females.
2. After birth.
3. Not easy to classify.
4. Monocular differences.
5. VA and visual fields may be affected.

Question 2

Describe the appearance of blue- yellow blindness and where is it found?

Answer 2

Appearance: blue- yellow appearance changes 1st then red- green preserved longer.
Found in retinal diseases.

Question 3

Describe the appearance of progressive red- green blindness and where is it found?

Answer 3

Colour vision is totally disturbed. Blue- yellow is changed, but deterioration most in red-green.
Found in: optic nerve to the cortex.

Question 4

Describe type 1,2,3 classes and colours they defect?

Answer 4

Type 1: Red- green (similar to protan)
Type 2: Red- green (similar to deutan)
Type 3: Blue- yellow (similar to tritan)

Question 5

What class of defect is assosiated with cataract, glaucoma, AMD and Diabetic retinopathy?

Answer 5

Type 3 (Blue- yellow)

Question 6

What is the most common class of acquired defect?

Answer 6

Blue- yellow
(Type 3)

Question 7

Where does type 3 defect occur (position in the visual pathway)

Answer 7

Can occur anywhere in the visual pathway

Question 8

What is the most common pathologies seen in practice?- in anterior eye?

Answer 8

Cataracts

Question 9

Describe what happens to the lens and absorption of light with patients that have cataracts?

Answer 9

As we age, lens starts to turn yellow and absorb short wavelengths- reducing sensitivity to the blue spectrum.

Question 10

What type of defect is cataract- in terms of class?

Answer 10

Type 3 (blue- yellow)

Question 11

What is the clinical importance of testing colour vision?

Answer 11

Can help identify early onset of retinal diseases.

Question 12

What ocular condition is the most prevalent cause of visual loss in elderly people in the UK?

Answer 12

AMD
Type 3 (blue- yellow)

Question 13

What ocular condition is the most common cause of blindness in working age group in the UK?

Answer 13

Diabetic Retinopathy

Question 14

What happens to patients before they have diabetic retinopathy?

Answer 14

Colour vision is lost 1st before retinopathy

Question 15

What is the class/ type of defect for diabetic retinopathy?

Answer 15

Type 3 (blue-yellow)

Question 16

What causes the damage in primary open- angle glaucoma?

Answer 16

Damage is due to increased pressure on the optic nerve i.e, ganglions are dying

Question 17

What is the class/ type of defect for primary open- angle glaucoma?

Answer 17

Type 3 (blue- yellow)

Question 18

In any condition which one is defected 1st: Colour vision or visual feilds?

Answer 18

Colour vision

Question 19

Which cones are the most sensitive to raised pressure?

Answer 19

Blue cones

Question 20

Are patients with suspected acquired CV defects tested monocularly or binocularly?

Answer 20

Monocularly

Question 21

What colour blindness is seen with optic neuritis?

Answer 21

Progressive red- green blindness

Question 22

What is optic neuritis?
What causes it ?

Answer 22

Inflammation of optic nerve head.
Caused by: demyelination of optic nerve.

Question 23

What is the likely chance of colour vision defect seen in optic neuritis?

Answer 23

100% colour vision defect is seen

Question 24

What is the most common sign in that patients with optic neuritis notice? - what sign is noticed by patients?

Answer 24

Pain with eye movements

Question 25

If a patient is diagnosed with optic neuritis, how can this diagnoses be supported/ tested?

Answer 25

Test colour vision to help diagnosis

Question 26

Colour vision defects generally the result of a vascular lesion caused by? (2)

Answer 26

1. Trauma
2. Brain Damage

Question 27

Achromatopsia is caused by damage to what part of the brain?

Answer 27

V4

Question 28

What is bilateral achromatopsia?

Answer 28

Complete loss of colour vision: black and white vision.

Question 29

What is agnosias?

Answer 29

Object recognition defect.

Question 30

What is anomia?

Answer 30

Unable to differentiate between colours

Question 31

What is hemi(semi)achromatopsia?

Answer 31

Damage to one side of the brain that causes partial colour vision defect

Question 32

How can medications cause toxicity that leads to colour vision defects?

Answer 32

If medication is prolonged or dose is exceeded.

Question 33

Colour vision defects can be used to monitor medication therapy, why?

Answer 33

They can cause visual losses

Question 34

What is cyanopsia?

Answer 34

When a patients cataract is removed, they have a blue tinge to their vision.
This lasts for 2-3 weeks after cataract is removed.

Question 35

3 likely causes of acquired colour vision defect?

Answer 35

1. Pathology
2. Toxins/ medication
3. Trauma