2 - Opth - Cataracts

Question 1

The lens

• structure?
• new fibres from?

Answer 1

Crystalline, inner nucleus of older inactive cells, cortex, outer anterior epithelium of active cells
whole lens is encapsulated
new lens fibres arise from differentiation epithelial cells at the lens equator

Question 2

Cataracts - what?

• incidence and age?
• main cause of?
• due to?

Answer 2

opacity on/in lens
increases with age - 30% >65, 75% by 75
main cause of blindness
accumulation of water or denaturation of lens proteins

Question 3

typical presentation of cataracts?

Answer 3

vision change - reduced acuity/contrast/colour sensitivity, glare, ghosting, monocular diplopia (double in one eye)

change in refraction

Question 4

5 main aetiologies of PREsenile cataracts

Answer 4

congenital
metabolic
drug induced
trauma
secondary/complicated

Question 5

Congenital aetiology

• most common congenital type?
• may cause?
• when do they require urgent removal? risk of?
• 3 maternal causes
• 3 other causes

Answer 5

• often polar, zonular
• may cause white reflex - but exclude retinoblastoma
• urgent removal is impairing vision - risk of lazy eye (amblyopia)
• rubella (50% if 1/2 trimester infection), toxoplasmosis, CMV
• Thalidomide, steroids, familial

Question 6

Metabolic causes of cataracts

4 things

Answer 6

may be reversible if corrected within 3 months

• DM - may accelerate age related cataracts or lead to snowflake cataracts
• galactosaemia (oil droplet appearance)
• hypocalcaemia
• wilsons disease (redbrown sunflower appearance)

Question 7

3 drug inducing causes of cataracts

Answer 7

amiodarone
steroids
miotics

Question 8

Trauma associated cataracts - 5 things

Answer 8

penetrating injury
blunt injury
glass blowers (infrared radiation)
electric shock
ionising rad

Question 9

Secondary/complicated causes of Cataracts - 7

Answer 9

uveitis
atopic dermatitis
high myopia
glaukomflecken (prev angle closure glaoucoma flecks)
downs syndrome
Myotonic dystrophy (christmas tree pattern)

Question 10

Nuclear cataracts -

• position?
• what pts?
• why happens?
• possible associations?

Answer 10

• central portion of lens opacity
• typically older pts
• accelerated new fibre creation - compresses nucleus of lens
• milk intake and smoking

Question 11

Nuclear cataracts -

- effect on vision and why?

Answer 11

• distance vision affected more than near vision
• brown-yellow hue - blocks blue wavelength -> poor night vision, light excessively intense
• change refractive index of lens - myopic shift - may present with change in glasses/”second sight”

Question 12

Posterior Subscapular cataract -

• appearance?
• may in what pts?
• associations? 3

Answer 12

granular appearance
may occur in younger pts
ass w/ DM, Steroids, Uveitis

Question 13

Posterior Subscapular cataract -

- effect on vision?

Answer 13

• early visual loss due to pos of opacity
• near vision affected more than distance vision
• reduced vision in bright light, glare or halos occur

Question 14

Cortical cataracts -

• what opacifies?
• configuration/appearance?
• effect on vision?

Answer 14

the lens cortex opacifies
radial spoke like configuration
may not affect vision unless on the visual axis
may cause monocular diplopia

Question 15

Cortical cataracts - associations? 4

Answer 15

old age
DM
UV exposure
Radiotherapy

Question 16

3 classification of cataracts by their stage of development

Answer 16

immature - present but not impairing - red reflex present

mature - lens completely opaque

hypermature (morgagnian) - lens small and wrinkled due to water leakage - risk of glaucoma

Question 17

(general) Presentation of cataracts - 6

Answer 17

• decreased acuity eg difficulty reading/with faces
• decreased colour sensitivity
• impaired depth perception
• dazzling and halos (if central - post subcapsular)
• monocular diplopia (cortical)
• acuity not improved by pinhole

Question 18

DDX cataracts

Answer 18

AMD
Presbyopia
Retinal disease

Question 19

3 Investigations for cataracts

Answer 19

Slit lamp examination
Biometry - keratometry and A-scan (for axial length)
B-scan if suspect retinal pathology and fundus cannot be viewed through cataract

Question 20

Management of cataracts

Answer 20

Phacoemulsification and intra-ocular lens (IOL) implant

Question 21

Describe the management of cataracts

Answer 21

day case surgery
small 3mm incision in cornea
lens broken up by US and aspirated
lens implant unfolded into capsule
-hole heals without sutures

Question 22

Early complications of Phacoemulsification and IOL implant (5)

Answer 22

• rupture of capsule and vitreous loss 4%
• iris trauma
• choroidal haemorrhage
• vitreous haemorrhage
• ENDOPTHALMITIS infection - 0.1%

Question 23

Late complications of Phacoemulsification and IOL implant (5)

Answer 23

POSTERIOR CAPSULE OPACIFICATION - 20% - months/years - treated with YAG laser

• retinal detachment 1%
• glaucoma
• lens dislocation
• macular oedema