7267880
Description
Flashcards by Liam Musselbrook, updated more than 1 year ago
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Created by Liam Musselbrook
about 8 years ago
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| Question | Answer |
| The lens: what's it comprised of? | Inner nucleus of old inactive cells, cortex and outer anterior epithelium (active cells) Whole lens is encapsulated |
| What is a cataract and what causes it? | Opacity on or within the lens Either the accumulation of water or the denaturation of proteins within the lens |
| How might a cataract typically present? | Reduced acuity/contrast Decreased colour sensitivity Monocular diplopia Glare, ghosting Decrease in refractiom |
| Congenital aetiology of presenile cataracts | Congenital cataracts often polar, zonular Rubella - 50% if infected in 1st/2nd trimester Toxoplasmosis, CMV, Thalidomide, steroids Familial Down’s syndrome Lowe’s syndrome Myotonic dystrophy |
| Metabolic aetiology of presenile cataracts | Diabetes mellitis (accelerate age-related cataracts or cause snowflake caracts) Galactosaemia Hypocalcaemia Wilson's disease |
| Pharmacological aetiology of presenile cataracts | Steroids Miotics Amiodarone |
| Trauma aetiology of presenile cataracts | Penetrating injury Blunt injury Glass Blower’s cataract (infrared radiation) Electric shock Ionising radiation |
| Nuclear cataract | Typically older patients Central portion becomes opaque Affects distance vision more than near Poor night vision, lights seem excessively intense Change refractive index of lens - Myopic shift |
| Post subcapsular cataract | Granular appearance May affect younger patients Affects near vision more Poor vision in bright light - glare, halos Associations: diabetes, steroids, uveitis |
| Cortical cataracts | Opacification of lens cortex Radial spoke-like configuration May not affect vision unless on the visual axis May cause monocular diplopia Associations: age, diabetes, UV, radiotherapy |
| Classification of cataract by development | Immature: not visually- impairing, red reflex present Mature: lens completely opaque Hypermature (Morgonian): lens becomes small and wrinkled due to leakage of water - risk of glaucoma |
| Differentials for cataracts | Macular degeneration Prysbyopia Retinal disease |
| What is the treatment for | Phacoemulsification + intra-ocular lens (IOL) implant |
| What are the complications of cataract surgery? | Rupture of capsule and vitreous loss (4%) Trauma to iris Choroidal haemorrhage Vitreous haemorrhage Endopthalmitis Late: Posterior capsule opacification, Retinal detachment (1%), Glaucoma, Lens dislocation, Macular oedema |
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