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EYE DISEASE - Coggle Diagram

- - - - due to lens hardening
        
        near image focused behind retina
        
        bifocal or multifocal glasses
  - - - distant images focused in front of retina
        
        concave/minus lens (diverges light)
  - - - distant images focused behind retina
        
        convex/plus lens (converges light)
- - - - cataract surgery
        
        capsulorhaxis
        
        remove cataract through opening via phacoemulsification (US)
        
        place intraocular lens implant into lens capsule (still attached to ciliary body and zonules)
- - - - main cause of blindness in diabetes patients
      - neovascularisation
        
        vitreous haemorrhage, fibrosis, tractional retinal detachment
        
        new vessels on disc or elsewhere (NVE)
        
        preretinal haemorrhages can only occur in PDR
        
        surgery
        
        rubeosis (new vessels in iris)
        
        block drainage
        
        increased intraocular pressure
        
        neovascular glaucoma
      - LASER panretinal photocoagulation
        
        reduces VEGF drive and therefore neovascularisation
      - anti-VEGF injections (but need to be given repeatedly)
    - - microaneurysms, intraretinal haemorrhages, vascular changes, hard exudates, cotton wool spots, intraretinal microvascular abnormalities (IRMA)
    - - main cause of visual impairment in diabetes patients
      - can occur in PDR/NPDR
      - clinically significant (CSME)
        
        hard exudate with thickening of retina ≤500 µm (1/3 of disc) from centre of macula
        
        vision loss
        
        if vision is normal, manage conservatively
        
        non-centre involved DMO
        
        laser
        
        centre-involved DMO
        
        anti-VEGF injections intravitreally
        
        people who have already undergone anti-VEGF injections or had cataract surgery have intravitreal steroids
        
        retinal thickening of 1 disc diameter+, any part of which is within 1 disc diameter of centre of macula (DISC within DISC)
      - OCT - differentiate retinal fluid and cysts
    - - diabetes patients screened every 2 years
        
        screened yearly if diabetes≥15 years, poor glycaemic control (HbA1c >8%), systemic disease (diabetic complications), indigenous or NSE
  - - - thrombus occurs at arteriovenous crossing point secondary to atherosclerosis of retinal artery
        
        compression/occlusion of retinal veins
    - - atherosclerosis of adjacent retinal artery causes localised turbulence of venous flow
        
        thrombus occludes central retinal vein near lamina cribrosa
        
        ischaemic CRVO
        
        high risk for neovascular glaucoma
        
        visual impairment caused by macular oedema or ischaemia
        
        intravitreal anti-VEGF injections for macular oedema
        
        laser mostly used for ischaemia and retinal neovascularisation
    - - Virchow's triad: blood flow stasis, vessel wall disease, hypercoagulability
  - - - 10% of AMD patients but causes 90% of vision loss
      - choroidal neovascular membrane
        
        abnormal vessels in choroidal space leak fluid
        
        if extrafoveal
        
        direct argon laser (destructive)
        
        pigmented epithelium detachment (elevated/dome-shaped)
        
        subretinal fluid
        
        loss of normal foveal dip
        
        fibrosis (once cleared)
      - OCT and FFA
      - anti-VEGF injections (mainstay) e.g. ranibizumab, aflibercept
        
        photodynamic therapy for polyps
    - - 90% of AMD patients but causes 10% of vision loss
      - usually not associated with vision loss
        
        drusen
        
        geographic atrophy
        
        vision tends to be poorer than drusen
        
        yellow circular deposits (multiple or singular)
        
        intermediate
        
        AREDS-formulated antioxidants/vitamins
      - cessation of smoking
        
        antioxidant supplements