Cataract

Question 1

What is a cataract?

Answer 1

Any opacity (loss of transparency) of the lens
The cloudiness makes it more difficult for light to react retina, thus causing reduced/ blurred vision

Question 2

A cataract may result from disruption to the…

Answer 2

Lens fibre configuration, capsule or epithelium

Question 3

What is the most common cause?

Answer 3

Increasing age

Question 4

Are cataracts more common in men or women?

Answer 4

Women

Question 5

Other than old age, what else can cause cataracts?

Answer 5

Trauma - direct injury to lens, electric shock/ lightening
Smoking and alcohol
Systemic disease: DM, myotonic dystrophy, neurofibromatosis type 2
Drugs: steroids, amiodarone, allopurinol
Hypocalcaemia
Sunlight exposure
Radiotherapy
HIV positive

Question 6

How do patients typically present?

Answer 6

Gradual onset of:
Reduced vision
Faded colour vision 
Glare - light appears brighter than usual 
Halos around light
Difficulty driving at night
Loss of stereopsis - affect distance judgement (perception of depth)
Monocular diplopia 

Unilateral cataracts are often unnoticed

Question 7

How can cataracts be classified?

Answer 7

Nuclear
Subcapsular
Cortical

Question 8

Where are subcapsular cataracts located and what do they look like?

Answer 8

Directly under lens capsule

Granular or plaque like appearance

Question 9

What symptoms are associated with subcapsular cataracts?

Answer 9

Near vision affected more than distance as opacity at nodal point of eye

Question 10

What are subcapsular opacities generally caused by?

Answer 10

Steroid use

Question 11

Where are nuclear cataracts found?

Answer 11

Involve the lens nucleus

Yellowish brown due to deposition of urochrome pigment

Question 12

What symptoms are associated with nuclear cataracts?

Answer 12

Myopic due to increased refractive index of lens
Dulls colour - more yellow/ brown
Common in old age

Question 13

Where are cortical cataracts found?

Answer 13

Cortex of lens

Radial spokes in periphery

Question 14

What symptoms are associated with cortical cataracts?

Answer 14

Milder effects on vision
Astigmatic changes
Trouble more in dark when pupil wider and exposes more of cataract

Question 15

What signs are associated with cataracts?

Answer 15

Defect in red reflex (cataract prevents light getting through to retina)

Question 16

What is the red reflex?

Answer 16

The red/ orange reflection seen through an ophthalmoscope when light shone on retina

Question 17

What investigations should be done?

Answer 17

Ophthalmoscopy done after pupil dilation - normal fundus and optic nerve
Slit lamp examination- visible cataract

Question 18

Are cataracts the leading cause of curable blindness worldwide?

Answer 18

Yes

Question 19

Cataracts are found in what percentage of over 65s?

Answer 19

75%

Question 20

How do cataracts present in children?

Answer 20

Squint
White pupil
Nystagmus

Question 21

What is astigmatism?

Answer 21

When eye shaped more like rugby ball than football - light focused at more than one place in the eye.

Causing: blurred vision, headaches, eye strain

Alongside short or long sighted

Question 22

What non surgical management options can be taken?

Answer 22

Stronger glasses/ contacts
Encourage use of brighter lighting
Sunglasses

Ways to optimise vision - do not actually slow down progression of cataracts

Question 23

What is the only effective treatment for cataracts?

Answer 23

Surgery

Question 24

What is the name of the most common surgical technique for cataract surgery?

Answer 24

Phacoemulsification

Question 25

Explain the process of phacoemulsification

Answer 25

Usually under local anaesthetic, patent prone
Entry to eye via limbus (peripheral cornea)
Lens removed by phacoemulsion - US breaks it up and it is aspirated into cannula
Incision slightly enlarged and artificial lens implanted
New lens calculated to correct the patients’ refractive error

Patient can usually go home same day with a dressing. Full activities can be resumed next day.

Question 26

NICE suggests that a referral for surgery should depend on…

Answer 26

If visual impairment present
Impact on QOL
Patient choice 
Whether one or both affected 
Risks of surgery

Question 27

What are some complications of surgery?

Answer 27

Posterior capsule thickening of the lens capsule - can opacify
Endophthalmitis- inflammation of aqueous and/or vitreous humour
Retinal detachment
Posterior capsule rupture

Question 28

What are some preventative measures?

Answer 28

Sunglasses
Reduce oxidative stress - vit c
Stop smoking

Question 29

If there is a congenital cataract, the patient needs to be referred to ophthalmologist urgently for surgical consideration. How soon does integration need to be done?

Answer 29

1st 6 weeks of life (latent period of visual development)

To prevent significant deprivation amblyopia

Question 30

What percentage of congenital cataracts have a genetic cause?

Answer 30

50%

Question 31

What screening should be done if patient has congenital cataracts?

Answer 31

TORCH screen = group of blood tests to check for several infections in newborn 
Toxoplasmosis 
Rubella
Cytomegalovirus 
Herpes simplex
HIV

Question 32

If a cataract develops in first 6 months of life, what is it called?

Answer 32

Infantile cataract

Question 33

What is amblyopia?

Answer 33

When the visual system is prevented from developing properly - particularly if brain doesn’t get chance to see clear images in first few months of life
(If child has unilateral cataract, brain may favour images from the good eye)

Question 34

Other than infection, what else can cause cataracts?

Answer 34

Metabolic diseases
Genetic e.g Down syndrome
Undetermined cause