Cataract

"opacification of the naturally crystalline lens"
3 types
- nuclear sclerosis- lens becomes yellow/brown
- cortical
- posterior subcapsular
assoc w/ gradula deterioration of vision
commonest cause of blindness worldwide
30% have other eye problems
- 11% glaucoma
- 17% ARMD
- 3% diabetic retinopathy
incr incidence w/ ageing pop
57% who have ctaract surgery have another condition
- 30% HTN
- 18% arthritis
- 11% diabetes

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Causes of cataracts

age related (commonest)
secondary to ocualr disese
- e.g. post inflammatory, uveitis > post subcaps cataract
secondary to systemic disease
- e.g. DM
traumatic - lens capsule disruption
drug induced
- systemic corticosteroids > post subcaps c
congenital

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symptoms
- gradual blurred, misty vision
- glare
examination
- pupils appear grey/white with pen torch
- nuclear sclerotic c may appear yellow/brown
- reduced red reflex usng a direct ophthalmoscope (NB indirect ophthalmoscope= appears upside down)

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D- nuclear sclerosis (most common)
A, B, C- cortical
E -posterior subcapsular (caused by corticosterois, uveitis)
F-hypermature: lens proteins completely opaque and liquified (mature=completely opaque)

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indications for treatment
- level vision resricts normal activity
- pt factors e.g. if young may need to drive
- ocular factors- some types of cataracts can induce glaucoma or uveitis so must remove
refraction - myopic spectacles
surgery (most common operation under NHS)
- removal by phakoemulsification and implantation of artificial intraocular lens
- remove whole lens except for posterior capsule
- once removed the eye is highly hypermetropic so insert artificial intraocular lens (IOL)
- under LA - day case
- 4mm incision, remove anterior lens capsule, high speend ultrasonic tip cuts nucleus into tiny bits and aspirates them, irrigation and aspiration of remaining cortex, insert foldable IOL
- no sutures
- complications: peri-op - rupture of posterior capsule (3%)
  - post-op - endophthalmitis (0.1%), haemorrhage, uveitis, glaucoma, macular oedema, retinal detachement, opacification of posterior lens capsule (late)

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