Visual Defects

Question 1

What is a cataract?

Answer 1

Opacifications (cloudy areas) within the lens of the eye

Question 2

Describe the pathophysiology of cataracts

Answer 2

1. Lens epithelium matures
2. Cells lose their contents, and the nucleus disappears
3. Leaving fibres
4. Degenerative changes in these fibres cause opacifications

Question 3

What visual symptoms are typical for cataracts?

Answer 3

(1) Gradual visual loss with blurred/hazy vision

(2) Glare and is worse at night

(3) Loss of the red reflex

Question 4

What is the management for cataracts?

Answer 4

Surgical removal with intra-ocular lens implant if patient is symptomatic

Question 5

What are the complications of cataract surgery?

Answer 5

(1) Posterior lens capsule opacification

= cloudiness that forms on the back of the lens capsule after cataract surgery, causing blurry vision. Treated with a laser

(2) Endophthalmitis
= inflammation of aqueous and/or vitreous humour

(3) Retinal detachment
= ‘curtain’ descending over the peripheral visual field, significant floaters, and flashes of light

Question 6

A 72-year-old woman presents with a red, painful eye to eye casualty. The pain started suddenly this morning, and her vision became blurry in the affected eye.

On examination, the eye looks red, her eyelid is swollen, and there is a small hypopyon on closer inspection. Her vision appears blurry in the affected eye, and she can only see moving fingers at a distance of one meter. On fundoscopy, periphlebitis is observed.

This is the first time this has happened to her, and she is otherwise well, other than a cataract surgery she had 5 days ago.

What is the most likely diagnosis?

Answer 6

Endophthalmitis

Question 7

Posterior subcapsular cataracts are located behind the capsule in the visual axis. They usually have a fast progression and are associated with what things?

Answer 7

diabetes, steroids and hypermetropia

Question 8

When should cataract removal operations be rationed on the basis of visual acuity?

Answer 8

Never

Question 8

Causes of cataracts

Answer 8

1. Normal ageing - most common
2. Smoking
3. Increased alcohol consumption
4. Trauma
5. Diabetes mellitus
6. Long-term corticosteroids
7. Radiation exposure
8. Myotonic dystrophy
9. Hypocalcaemia

Question 9

What is refractive error?

Answer 9

Any abnormality in the eye’s focusing, causing light not to focus properly on the retina

Question 10

Define emmetropia

Answer 10

Normal vision with light focused directly on the retina

Question 10

What is ametropia?

Answer 10

A refractive error where light focuses in front of or behind the retina

Question 10

What does anisometropia mean?

Answer 10

Significant difference in refractive error between the two eyes

Question 11

Symptoms of myopia?

Answer 11

1. Clear near vision
2. Blurry distance vision

Question 11

What causes myopia (short-sightedness)?

Answer 11

Eye too long or too strong, light focuses in front of the retina

Question 12

How is myopia corrected?

Answer 12

Concave (negative) lenses

Question 12

Name two complications of myopia

Answer 12

Retinal detachment and primary open-angle glaucoma

Question 13

What causes hyperopia (farsightedness)?

Answer 13

Eye too short, light focuses behind the retina

Question 14

Symptoms of hyperopia?

Answer 14

1. Blurred near vision
2. Clear far vision

Question 15

How is hyperopia corrected?

Answer 15

Convex (positive) lenses

Question 16

What complication is associated with hyperopia?

Answer 16

Closed-angle glaucoma

Question 17

What is astigmatism?

Answer 17

Unequal curvature of the eye causing distorted vision at all distances

Question 17

How is astigmatism corrected?

Answer 17

Cylindrical lenses

Question 17

What causes presbyopia?

Answer 17

Age-related loss of lens accommodation

Question 18

What are presbyopia symptoms?

Answer 18

1. Blurred near vision 2. Myopia may temporarily improve near vision

Question 18

How is presbyopia treated?

Answer 18

Reading glasses with convex (positive) lenses

Question 19

What does a Snellen chart measure?

Answer 19

Visual acuity — how well someone can see at a distance

Question 20

What is the purpose of a pinhole occluder in vision testing?

Answer 20

To check if blurred vision is caused by a refractive error

Question 21

What should be the next step if blurred vision is gradual, improves with a pinhole, and has no other symptoms?

Answer 21

Refer to an optician for correction

Question 21

What does it mean if vision improves with a pinhole occluder?

Answer 21

The blurred vision is likely due to a refractive error

Question 22

When should patients be urgently referred to ophthalmology?

Answer 22

If they have associated symptoms like visual loss or eye pain

Question 23

A 46-year-old man attends his GP with worsening vision. He reports that his vision has recently become more blurry, especially when reading. He has no eye pain, redness, diplopia or systemic symptoms. You measure his visual acuity on a Snellen chart and find it to be 6/12 bilaterally. What step is most suitable to investigate a refractive error?

Answer 23

Use of a pin-hole occluder

Question 24

What is a squint (strabismus)?

Answer 24

When the eyes don’t align properly and fail to focus together on an object (poor fusion)

Question 25

What are risk factors for squint?

Answer 25

1. Premature birth 2. Cerebral palsy 3. Family history

Question 26

What symptoms do patients with squint have?

Answer 26

1. Eye misalignment 2. Reduced vision 3. Double vision = diplopia 4. Eye strain = asthenopia

Question 26

What sign is seen on eye exam for squint?

Answer 26

Asymmetrical corneal light reflex

Question 27

What is the cover test?

Answer 27

A test where covering one eye reveals the direction the other eye moves to align

Question 27

What does inward movement during the cover test indicate?

Answer 27

Exotropia (eye turns outward at rest)

Question 28

What does outward movement during cover test indicate?

Answer 28

Esotropia (eye turns inward at rest)

Question 29

What does downward movement during the cover test indicate?

Answer 29

Hypertropia (eye is higher)

Question 30

What does upward movement during the cover test indicate?

Answer 30

Hypotropia (eye is lower)

Question 31

Why patch the good eye in infants with squint?

Answer 31

To force the brain to use the weaker eye and prevent amblyopia (‘lazy eye’)

Question 32

A mother brings her 7-year-old son into the surgery due to concerns about his eyes. She thinks her son's left eye is 'turned outwards'. Her son denies any changes in his vision. Examination of the child reveals a left exotropia. The child is asked to cover his right eye whilst focusing on a fixed point, at which point the left eye moves medially to take up fixation. What is the most appropriate management of this patient?

Answer 32

Always refer children with a squint to ophthalmology

Question 33

A mother brings her son in to surgery as she suspects he has a squint. She thinks his right eye is 'turned inwards'. You perform a cover test to gather further information. Which one of the following findings would be consistent with a right esotropia?

Answer 33

On covering the left eye the right eye moves laterally to take up fixation

Question 34

What is a simple and effective method that can be used to screen for strabismus (squint) in children?

Answer 34

The corneal light reflection test

Question 35

Failure to correct childhood squints may lead to what occurring?

Answer 35

Amblyopia - lazy eye