Cataracts

Question 1

What are the causes of acquired cataracts?

Answer 1

1. Age-related (?90%)
2. Ocular diseases (diabetes mellitus)
3. Drug-induced (corticosteroids)
4. Chronic alcohol and tobacco use
5. Trauma
6. Physically related conditions (radiation, excessive sunlight or UVB exposure)

Question 2

What are the different classifications of cataracts, and which is the most common?

Answer 2

Based on morphology:

1. Cortical cataract (anterior/posterior) - most common
2. Nuclear cataract
3. Subcapsular cataract (anterior/posterior)

Question 3

What is a cortical cataract?

Answer 3

• The most common type
• Originated at the outer layer of the lens and grows towards the centre
• Forms a wedge-shaped opacity

Question 4

What is a nuclear cataract?

Answer 4

• Cataract that affects the centre of the lens

- Appears as a yellow-brown discolouration of this area

Question 5

What is a subcapsular cataract?

Answer 5

• Cataract that manifests directly under the lens capsule

- Usually in the posterior lens (rapidly progressive) but can also occur in the anterior lens

Question 6

Describe the stages of cataract progression.

Answer 6

1. Immature cataract:
   - early stage of cataract progression
   - red reflex still present allowing for visualisation of the retina
2. Mature cataract:
   - advanced stage in cataract progression
   - red reflex is absent
   - white-yellow discolouration of the lens due to complete clouding
   - vision may be reduced to light perception only
3. Hypermature cataract:
   - end-stage
   - complete clouding of the lens due to liquification of the cortex
   - nucleus often sinks into the cortex and appears brown

Question 7

What are the clinical features of acquired cataracts?

Answer 7

• Reduced visual acuity: blurred, cloudy, or dim vision (especially at night)
• Impaired vision (painless and often bilateral)
• Glare; associated with haloes around lights
• Second sight: a temporary improvement in near vision (esp in nuclear cataracts)
• Monocular diplopia: double vision that disappears when the affects eye is covered or shut
• Change in colour perception

Question 8

What are typical fundoscopy and slit-lamp findings in cataracts?

Answer 8

1. Fundoscopy:
   - changes to red reflex - opacities, darkening, absent or decreased red reflex
   - obscuration of ocular fundus detail
2. Slit-lamp:
   - Grey, white, yellow, or brownish clouding of the lens
   - Traumatic cataract: rosette/stellate-shaped clouding of the lens

Question 9

How can cataracts be prevented?

Answer 9

• Smoking cessation
• Management of medical conditions associated with increased cataract risk (diabetes, HTN, obesity)
• Avoidance of UVB radiation (wear sunglasses)
• Wearing eye protection during activities that carry risk of penetrating trauma

Question 10

What is the non-surgical management of cataracts?

Answer 10

*Do not slow the progression of cataract development, and patients will eventually need surgery

Optimise vision by giving stronger glasses/lenses and using brighter lighting

Question 11

What is the surgical management of cataracts?

Answer 11

Referral for surgery should be dependent upon whether a visual impairment is present, impact on QoL, and patient choice

Types of surgery:

• Phacoemulsification (liquefaction and aspiration of lens nucleus)
• Extracapsular cataract extraction
• Intracapsular cataract extraction
• Manual small incision cataract surgery

Question 12

What are the potential complications of cataract surgery?

Answer 12

• Posterior capsule opacification (thickening of lens capsule)
• Retinal detachment
• Posterior capsule rupture
• Endophthalmitis (inflammation of aqueous and/or vitreous humour)