Cataracts Flashcards
What are cataracts?
clouding of the lens of the eye caused by protein breakdown
What is the most common cause of blindness worldwide?
Cataracts
Who are cataracts particularly prevalent in?
Elderly
What is the role of the lens?
to focus light on the retina
What structure attaches the lens to the ciliary body?
suspensory ligaments
Contraction of the ciliary body has what effect on the shape of the lens?
The lens thickens
Relaxation of the ciliary body has what effect on the shape of the lens?
the lens narrow
What is the lens nucleus?
Middle aspect of the lens
What is the lens cortex?
Outer aspect of the lens
What is the lens capsule?
The membrane surrounding the lens
What are nuclear cataracts?
Nuclear cataracts are caused by sclerosis of the lens nucleus and are common in old age.
What are 2 typical symptoms of nuclear cataracts?
- Myopia
- Colours appearing dull
Why does myopia occur in nuclear cataracts?
Myopia occurs as sclerosis changes the lens refractive index. Patients experiencing this symptom will often say that they previously needed reading glasses, but no longer require them.
What are the 3 types of cataracts?
- Nuclear
- Cortical
- Posterior subcapsular
What are cortical cataracts caused by?
Cortical cataracts are caused by opacifications of the lens cortex.
How does cortical cataracts present on oplthamoscopy?
the opacifications look like the spokes of a wheel around the edge of the lens
What are posterior subcapsular cataracts?
are caused by opacifications in the posterior aspect of the lens capsule
Who does posterior subcapsular cataracts typically affect?
- Younger patients
- Individuals taking steroids
What are 2 clinical features of cataracts?
- Patients complain of glare
- Posterior subcapsular cataracts often progress more rapidly than other types of cataracts.
Give 6 risk factors for cataracts?
1) increasing age
2) steroid use
3) alcohol
4) smoking
5) hypercalcaemia
6) diabetes
Give 5 presentations associated with cataracts:
- Slow reduction in visual acuity
- Progressive blurring of vision
- Colours becoming more faded, brown or yellow
- Starbursts appear around lights
- Loss of the red reflex
What colour is a cataract under an ophthalmoscope?
grey or white
What is the most common treatment for cataracts?
cataract surgery
What does cataract surgery involve?
drilling and breaking the lens, removing the pieces and implanting an artificial lens under local anaesthetic
What is endophthalmitis?
inflammation of the inner contents of the eye
Name a severe complication of cataract surgery:
endophthalmitis
How is endophthalmitis managed?
intravitreal antibiotics injected directly into the eye
