painless loss of vision

Question 1

Mrs RS is an active 70 year old woman with atrial fibrillation. As the FY1 you see her when she attends the A & E department with a complaint of loss of vision in the left eye, unaccompanied by pain. She thinks she may have had previous episodes that recovered and that the symptoms came on over a period of less than 30 minutes. She has not experienced associated headaches.

Answer 1

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Question 2

a) What is the most likely diagnosis?

Answer 2

Retinal Artery Occlusion

(assume that this time the visual loss will not be transient and is complete, making a diagnosis of RAO more likely)

Retinal artery occlusion may either be central retinal artery occlusion or branch retinal artery occlusion.

Question 3

b) Name 2 other causes of painless loss of vision.

Answer 3

• Retinal Vein Occlusion (Sudden)
• Retinal Detachment (Sudden)
• Vitreous Haemorrhage from any cause (Sudden)
• Neo-vascular or Atrophic AMD (Gradual)
• Chronic Open-Angle Glaucoma (Very Gradual)
• Optic Neuropathy (esp. non-arteritic ischaemic ON which causes sudden painless loss of VA)
• Diabetic Retinopathy (vitreous haemorrhage would cause sudden loss, but most retinopathy causes
  gradual loss)

Question 4

c) What 2 points from the history, as given above, help you to distinguish between the possible
causes of vision loss in this patient?

Answer 4

• AF → ↑ risk of Retinal Artery Occlusion due to embolus
• Absence of Headache → typical presentation of giant cell arteritis involves headache (but not always)
• Sudden Onset → narrows differential (vascular cause more likely)
• Age of patient
• Transient episodes

Question 5

d. What features of the ophthalmic examination would be important for you to note in this patient?
List 4 points.

Answer 5

• Visual Acuity: Reduced (<6/60)
• Visual Fields
• Pupillary reflex (direct and consensual): Afferent Pupillary Defect
• Red Reflex
• Fundoscopy:
  => Cherry-red Spot at Macula
  => Pale Fundus
  => Cattle-trucking in Retinal Arterioles (segmentation of the blood column in the arteries)

Question 6

e. What investigation would you perform with regard to the carotid artery?

Answer 6

Carotid ultrasound scan