what is a cataract?
opification of the natural crystalline lens
this causes a painless gradual deteriation of vision and is the commonest cause of blindness
what are the causes of cataracts?
age related- over 65 secondary to ocular disease secondary to systemic disease eg. diabetes mellitus traumatic - lens capsule disruption drug induced - systemic steroids congenital
what are the symptoms of cataracts?
- gradual onset of blurred misty vision
- glare
what examinations findings will you see with cataracts?
- grey/white pupil using a pen torch
- nuclear / sclerotic cataracts may appear yellow/ brown
- reduced red reflex
what are the different types of cataracts?
nuclear sclerosis - most common
cortical
posterior sub-scapular
you may get a mix of all the different types of cataract
(look in notes at how to differentiate between them using otoscopy)
how are cataracts treated?
there is currently no medical treatment for cataracts and the only option is surgery - removal of cataract by phacoemulsification and implantation of an artificial intraocular lens to correct refractive error.
not all cataracts will need operating on. There are specific indications for surgery:
- when the level of vision is restricting normal activity
- patient factors - age, occupation (eg. driver), ocular factors (eg. cataracts caused by diabetes or glaucoma)
people who do not have surgery can have glasses (myopic spectacle lens) which will alter the lens refractive index and help vision.
what are the complications of cataracts?
pre-operative
- rupture of the posterior capsule leading to vitreous loss
post-operative
- endophthalmitis - this is an ophthalmic emergency as a delay in treatment can lead to blindness
- haemorrhage, uveitis, glaucoma, macular oedema, retinal detachment,
- opacification of posterior lens capsule which is a late complication and occurs months or years following surgery. if the vision is significantly reduced then laser treatment is required to make a hole in the posterior capsule to clear the visual axis
