Cataract is the most common non-refractive cause of visual impairment worldwide
In simple terms = Opacification of the lens.
Not “a skin” growing over the lens as many people think!
- Main one is AGE!
- Smoking (as usual- if in doubt say smoking!)
- Alcohol use
- Other metabolic disorders eg fabry disease, hypocalcaemia, galactosaemia (you’ll get points for saying these)
- Systemic drugs (eg, corticosteroids)
- Painless loss of vision
- Misting or blurring
- Change in refractive error
- (in infants may cause amblyopia)
Diagnosis is best made with a dilated pupil
Examine with a slit lamp/ophthalmoscope- a cataract is seen as black against the red reflex
On the NHS;
- If the cataract is bad enough to cause sufficient visual symptoms- “reduction in quality of life”
- Vision worse than 6/12
Most common method of treatment of cataracts is phaecoemulsification- they dissolve the lens with ultrasound and replace it with plastic or silicone lens. This also corrects the refractive error. This is done as a day case using local anaesthetic with or without sedation. One eye is done at a time.
As with every surgery there are complications;
- Bleeding – choroidal haemorrhage
- Vitreous loss
- Endopthalmitis- a very nasty infective complication, but thankfully very rare (0.3%).
- Opacification of the capsule- treated by burning holes in the capsule with YAG laser
Sometimes pre-existing pathology is discovered from removing the cataract- as you can now see the Fundus a lot more clearly on slit lamp examination- e.g. AMD
- Most common cause of visual impairment worldwide
- Treat if affecting activities of daily living or VA <6/12
- Treatment is surgery
- Make patients aware of complications