cataracts

Question 1

def cataracts

Answer 1

opacification of the lens of the eye

Question 2

aetiology cataratcs

Answer 2

age - Majority of cases are idiopathic age-related (‘senile cataracts’).

in children many are genetic (?genetic in adult too)

systemic secondary causes

congenital secondary causes - congenital rubella syndrome

high myopia

smoking

alcohol excess

sunlight exposure

HIV +ve

local secondary causes

• previous eye trauma
• uveitis
• intraocular tumours

Question 3

systemic secondary causes of cataracts

Answer 3

dm - when cataract is found measure fasting plasma glucose

metabolic disorders (galactosaemia, hypocalcaemia, Wilson’s disease)

steroid use

dystrophia myotonica

skin disease (atopic dermatitis, scleroderma)

genetic syndromes - down’s

radiotherapy

Question 4

path cataracts

Answer 4

seen with slit lamp microscope

in early stages - compression of lens fibre in central portion of the lens (nuclear sclerosis)

gradual change of the crystaline lens nucleus from translucent to brown/grey

There may be areas of granular opacities (e.g. in posterior subcapsular sub-type).

Question 5

epi cataracts

Answer 5

Major cause of treatable blindness worldwide.

Cataracts are found in 75% of >65s but in only 20% of 45–65-year-olds

Question 6

sx cataracts

Answer 6

blurred vision

Unilateral cataracts are often unnoticed, but loss of stereopsis affects distance judgement

Bilateral cataracts cause gradual painless loss of vision (frequent spectacle changes as refraction changes) ± dazzle (esp. in sunlight) ± monocular diplopia

difficulties driving at night and haloes around street lights.

Glare from bright light, vision may worsen in bright light (especially with central lens opacity).

Some may notice that they can read without glasses (nuclear sclerotic cataractmay”lens-converging power).

children - squint, nystagmus, amblyopia (lazy eye)

Question 7

signs cataracts

Answer 7

loss of red reflex, hazy lens appearance

reduced visual acuity

opthalmoscopic classification is by lense appearance:

• immature catacracts - red reflex still present
• in dense cataracts - no red reflex or visible fundus
• nuclear cataracts
  
  • change the lens refractive index, dull colours - common in old age
• cortical cataracts
  
  • spoke like wedge opacities
  • milder effect on vision
• posterior sub-capsular cataracts
  
  • progress faster
  • cause classic glare from bright lights - even when acuity is only mildly affected
  • Subcapsular opacities (eg from steroid use) are just deep to the lens capsule—in the visual axis.
  • Dot opacities are common in normal lenses but are also seen in fast-developing cataracts in diabetes or dystrophia myotonica.

Question 8

ix cataracts

Answer 8

Unnecessary unless occuring at an early age or in background of systemic disease.