Cataract

Question 1

What is a cataract?

Answer 1

• Cloudy lesion (opacity) in the lens that can reduce the transparency of the lens
• Can affect different parts of the lens primarily

Question 2

Why does the lense appear cloudy in a cataract?

Answer 2

Chemical modification of the lens proteins –> change in lens colour

Question 3

What is the epidemiology of Cataracts?

Answer 3

Common

• increases with age (56% of >60 YO)
• More likely in females

Question 4

What is the aetiology of the development of cataract?

Answer 4

Age

• Or other reasons e.g. Trauma
• Chronic eye condition e.g. anterior uveitis, congestive angle-closure glaucoma and others
• Chronic systemic disease e.g. DMT2, , myotonic dystrophy, neurofibromatosis type 2, and severe atopic dermatitis
• Congenital abnormality in children

Question 5

What are risk factors for the development of a cataract?

Answer 5

• FH of age-related cataracts
• corticosteroid treatment
• Smoking
• prolonged exposure to ultraviolet B light
• Female gender

Question 6

What are the symptoms of a patient with cataract?

Answer 6

Painless, Progressive reduction in visual acuity and sharpness

• Blurred vision
• Worse seeing at night
• Difficulty reading text.
• Sensitivity to light and glare.
• ‘Halos’ around lights and double vision in a single eye.
• Polyopia (multiple images).
• Frequent changes of spectacle prescription as a result of cataracts developing.
• Difficulty recognizing faces.
• Problems watching television.
• Gradual reduction in perception of colour intensity (especially blues)

Question 7

Which investigations would you do in a patient with suspected cataract?

Answer 7

• Visual Acuity (Snellen chart)
• Ocular alignment and motility.
• Ophthalmoscopy:
  
  • Defect in red reflex
  • Normal Optic nerve and fundus
• Slit-lamp examination to physically examine the lens
  
  • an opacity can be seen in the lens if cataract is present
  • Cataract visible
• Intraocular pressure measurement
  
  • To rule out glaucoma, standard measurement
• A glare vision test
  
  • Reduced visual accurate (though maximal spectacle correction)

Question 8

Why does the vision become blury in a patient with cataracts?

Answer 8

Protein depositions in lense cause change in refractive pover of lense –> blurred due to no focal point