Sudden Loss Of Vision


Sudden loss of vision means sudden deterioration of vision, not necessarily blindness.

Is the loss of vision sudden or suddenly noticed ? i.e. unilateral field loss noticed
for the first time when the good eye is closed.

Cause of visual loss may be due to problems anywhere from the cornea to the visual cortex,
i.e. Bulbar or Cerebral. The 'Loss of Vision' may be associated with a quiet eye or a red
eye.

	
Always discuss with colleague or Ophthalmologist, seriously consider same day referral. 

Bulbar causes of 'Sudden loss of Vision':

(1) Those associated with a quiet eye

   (a) Retinal Artery Thrombosis,  Central or Branch occlusion with corresponding total or
       field loss. Look for precipitating factors -
                   Hypertension
                   AF 
                   Carotid Artery Stenosis
                   Smoking etc. 

       Fundus looks pale, arteries thin with little or no blood flow. Start Aspirin unless
       contraindicated.

   (b) Retinal Vein Thrombosis, Central or Branch thrombosis with corresponding  total or
       field loss. Fundus looks haemorrhagic, dilated veins - 'blood everywhere'. Start
       Aspirin unless contraindicated.

   (c) Temporal Arteritis. Very important because treatable, always consider diagnosis.
       Look for tender non pulsatile temporal arteries. Check ESR.  If in doubt give high
       dose (prednisolone 60mg) steroids and refer that day.

   (d) Retinal Detachment.  Treatable if diagnosed early, so always consider this diagnosis.
       Occurs in myopic eyes more frequently. May be superior retina (progresses more rapidly)            
       or inferior. Lesion may be very peripheral and difficult to see especially on a bright day.
       Onset may be associated with flashes of light and a shower of floaters or initially
       just a scotoma. Retinal tear +/- vitreous haemorrhage may occur.

   (e) Vitreous Haemorrhage.   Loss of red reflex.  May be associated with retinal detachment
       or trauma.  If dense, impossible to see retina or detachment.

   (f) Any long standing cause suddenly noticed -
                   Cataract
                   Chronic (wide angle) Glaucoma
                   Diabetic or Hypertensive Retinopathy etc.

(2) Those associated with a red eye

   (a) Iritis - May be associated with systemic conditions -
                   Ankylosing spondylitis
                   Ulcerative Colitis
                   Reiter's Syndrome

       There may be circumcorneal redness, Vertically oval pupil, Keratitic precipitates
       (Hypopyon). Corneal oedema - hazy pupil There is a risk of anterior and posterior
       Synechiae

                   Rx Atropine & Steroid Drops
                   Refer all initial episodes
                   ? refer recurrences.

   (b) Acute Glaucoma -

       Angle closure, NOT related to chronic glaucoma
       May be associated with Rubeosis Iridis in diabetic eyes - blocks canal of Schlemm
       Patients in pain may vomit & may need opiates
       Requires urgent referral.
       Eye is brick red - it really is a different colour.
       Fixed pupil, hazy cornea.

	
  (c) Keratitis - Inflammation of cornea. Corneal Ulcer - Beware Dendritic (Herpetic).
      Always stain red eyes
      BEWARE Contact Lenses
      Non traumatic ulcers should be referred.
      NEVER USE STEROID DROPS IN RED EYES WITHOUT EXCLUDING DENDRITIC ULCER (Slit lamp)


Retro-bulbar causes of 'Sudden loss of Vision':


(3) Causes behind the Globe	


  (a) Optic Nerve - Optic Neuritis (MS) - all movements of eye may be painful especially
      at extremes of gaze. May be a known case of MS or have other suggestive symptoms.
      Pale disc. Scotoma.

  (b) Optic Chiasma - Sometimes associated with tumour, often Pituitary. Craniopharyngioma,
      MS, Classical bitemporal field loss.

  (c) Optic Tract - Tumour, vascular, MS.  Homonymous Hemianopia.

  (d) Optic Cortex - Tumour, vascular, MS, Homonymous Hemianopia.

  Field defects associated with (c) & (d) may be complicated.	


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                                          Tutorial provided by John Julian - St Agnes - 1998