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  <head>
    <title>055-02 Visual localisation, sight-threatening emergencies, and systemic ocular disease</title>
    <ownerName>Integrated Medical Foundations</ownerName>
  </head>
  <body>
    <outline text="Localisation, emergencies, and systemic disease">
      <outline text="Localising visual failure">
        <outline text="Failed step: optics, receptors, nerve, alignment, cortex"/>
        <outline text="Monocular loss: eye or anterior pathway"/>
        <outline text="Homonymous loss: behind the chiasm"/>
        <outline text="Binocular diplopia resolves with cover: misalignment"/>
      </outline>
      <outline text="Acuity and examination">
        <outline text="Acuity first, each eye, usual correction">
          <outline text="Drops, pressure, pain can change it"/>
        </outline>
        <outline text="Record counting fingers to light projection"/>
        <outline text="Baseline and change set urgency"/>
        <outline text="Unseen disc recorded as not visualised">
          <outline text="Leads to dilated examination or imaging"/>
        </outline>
      </outline>
      <outline text="Phototransduction and retinal processing">
        <outline text="Light alters chromophore, activates opsin cascade">
          <outline text="Cyclic nucleotide falls, cell hyperpolarises"/>
          <outline text="Darkness gives tonic glutamate release"/>
        </outline>
        <outline text="ON and OFF bipolars code increments, decrements"/>
        <outline text="Ganglion output is processed, not a pixel copy"/>
        <outline text="Fovea trades convergence for acuity"/>
      </outline>
      <outline text="Pupils and visual fields">
        <outline text="Light reflex: afferent to midbrain, third-nerve efferent"/>
        <outline text="Relative afferent defect">
          <outline text="Light to worse eye: both pupils dilate"/>
          <outline text="Asymmetric retina or nerve, cannot tell which"/>
        </outline>
        <outline text="Anisocoria worse in light: larger pupil fails"/>
        <outline text="Anisocoria worse in dark: smaller pupil fails"/>
        <outline text="Chiasmal compression: temporal fields"/>
        <outline text="Tract to cortex: contralateral homonymous loss"/>
        <outline text="Temporal radiations upper, parietal lower fields"/>
      </outline>
      <outline text="Red eye and orbit">
        <outline text="Keratitis: staining, opacity, severe pain">
          <outline text="Urgent cultures, intensive organism-directed drops"/>
          <outline text="Patching or casual steroid speeds destruction"/>
        </outline>
        <outline text="Anterior uveitis: ciliary injection, small pupil, cells">
          <outline text="Steroid and cycloplegia after ophthalmic check"/>
        </outline>
        <outline text="Scleritis: boring pain waking sleep, vasculitis"/>
        <outline text="Orbital cellulitis: fever, proptosis, painful movement">
          <outline text="Watch nerve compression, sinus thrombosis"/>
          <outline text="Imaging, intravenous antibiotics, joint care"/>
        </outline>
      </outline>
      <outline text="Angle closure, chemicals, and trauma">
        <outline text="Angle closure: aqueous cannot reach meshwork">
          <outline text="Pain, halos, nausea, haze, mid-dilated pupil"/>
          <outline text="Laser relieves pupillary block"/>
          <outline text="Nausea must not suggest a gut diagnosis"/>
        </outline>
        <outline text="Chemical injury treated before history">
          <outline text="Irrigate until pH stays neutral"/>
          <outline text="Alkali saponifies and penetrates rapidly"/>
        </outline>
        <outline text="Penetrating trauma: rigid shield, no pressure">
          <outline text="Avoid tonometry, and magnetic resonance if metal"/>
        </outline>
      </outline>
      <outline text="Sudden painless loss and arteritis">
        <outline text="Arterial occlusion cuts inner-retinal perfusion">
          <outline text="Carotid or cardiac emboli, arteritis"/>
        </outline>
        <outline text="Transient monocular dimming is retinal ischaemia">
          <outline text="Serious even when examination normalises"/>
        </outline>
        <outline text="Venous occlusion: haemorrhage and oedema">
          <outline text="Signals pressure, diabetes, glaucoma, thrombosis"/>
        </outline>
        <outline text="Giant-cell arteritis infarcts the optic nerve">
          <outline text="Headache, scalp tenderness, jaw claudication"/>
          <outline text="Inflammatory markers occasionally normal"/>
          <outline text="Immediate high-dose steroid">
            <outline text="Fellow eye can go blind within days"/>
          </outline>
        </outline>
      </outline>
      <outline text="Retina, optic nerve, and diplopia">
        <outline text="Flashes: vitreous traction stimulates retina"/>
        <outline text="Sudden floaters or curtain: urgent dilated exam"/>
        <outline text="Macula-on detachment exceptionally urgent"/>
        <outline text="Optic neuritis: subacute, colour loss, painful">
          <outline text="Disc normal if inflammation posterior"/>
        </outline>
        <outline text="Ischaemic optic neuropathy: sudden, altitudinal"/>
        <outline text="Diplopia localised by position, lid, pupil">
          <outline text="Pupil-involving third palsy: aneurysm"/>
          <outline text="Internuclear ophthalmoplegia: medial fasciculus"/>
          <outline text="Fatigable ptosis: neuromuscular junction"/>
        </outline>
      </outline>
      <outline text="Glaucoma, diabetes, macula, and children">
        <outline text="Glaucoma is ganglion-cell and axon loss">
          <outline text="Progression at normal pressure occurs"/>
          <outline text="Pressure is the only modifiable factor"/>
          <outline text="Punctal occlusion cuts systemic absorption"/>
        </outline>
        <outline text="Diabetes: leakage, closure, ischaemia, growth factor">
          <outline text="Neovascularisation: bleeding, traction, glaucoma"/>
          <outline text="Rapid correction may transiently worsen"/>
        </outline>
        <outline text="Macular degeneration spares peripheral navigation">
          <outline text="New distortion needs rapid retinal therapy"/>
        </outline>
        <outline text="Child red reflex, leukocoria, strabismus: urgent"/>
      </outline>
      <outline text="Systemic window and discharge">
        <outline text="Papilloedema: raised intracranial pressure"/>
        <outline text="Safe habit: acuity, pattern, treat tissue first"/>
        <outline text="State driving and hazardous work limits"/>
        <outline text="Return signs: vision loss, pain, curtain"/>
        <outline text="Drops: name, eye, frequency, duration"/>
      </outline>
    </outline>
  </body>
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