An 84-year-old man presents with loss of vision in his left eye since the morning. He is otherwise asymptomatic and of note has had no associated eye pain or headaches. His past medical history includes ischaemic heart disease but he is otherwise well. On examination he has no vision in his left eye. The left pupil responds poorly to light but the consensual light reaction is normal. Fundoscopy reveals a red spot over a pale and opaque retina.
What is the most likely diagnosis?
Correct Answer E:
Sudden painless loss of vision:
The most common causes of a sudden painless loss of vision are as follows:
Ischaemic optic neuropathy:
Central retinal vein occlusion:
Vitreous haemorrhage:
Retinal detachment:
Differentiating posterior vitreous detachment, retinal detachment and vitreous haemorrhage:
Which one of the following is least recognized as a cause of tunnel vision?
Correct Answer C:
Tunnel vision:
Tunnel vision is the concentric diminution of the visual fields.
Causes:
A 70-year-old woman presents with loss of vision in her left eye. For the past two weeks she has painful frontal headaches and has been feeling generally lethargic. On examination visual acuity is 6/9 in the right eye but on the left side only hand movements can be made seen. Fundoscopy of the left side reveals a pale and oedematous optic disc.
Correct Answer E: This patient has likely developed anterior ischemic optic neuropathy on the left side.
Temporal arteritis:
Temporal arteritis is large vessel vasculitis which overlaps with polymyalgia rheumatica (PMR). Histology shows changes which characteristically 'skips' certain sections of affected artery whilst damaging others.
Features:
Investigations:
Treatment:
A 52-year-old old man who has a history of alcohol excess is brought to the Emergency Department by paramedics. He is a frequent attender and this time has a laceration on his scalp following a fall. Whilst examining him he seems confused and complains of problems with his vision.
Which one of the following is the most commonly found ocular abnormality in patients with Wernicke's encephalopathy?
Wernicke's encephalopathy:
Wernicke's encephalopathy is a neuropsychiatric disorder caused by thiamine deficiency which is most commonly seen in alcoholics. Rarer causes include: persistent vomiting, stomach cancer, dietary deficiency. A classic triad of nystagmus, ophthalmoplegia and ataxia may occur. In Wernicke's encephalopathy petechial haemorrhages occur in a variety of structures in the brain including the mamillary bodies and ventricle walls.
Treatment is with urgent replacement of thiamine.
Which one of the following is not a feature of background diabetic retinopathy?
Correct Answer C: Cotton wool spots are seen in pre-proliferative retinopathy.
Diabetic retinopathy:
Diabetic retinopathy is the most common cause of blindness in adults aged 35-65 years-old. Hyperglycaemia is thought to cause increased retinal blood flow and abnormal metabolism in the retinal vessel walls. This precipitates damage to endothelial cells and pericytes.
Endothelial dysfunction leads to increased vascular permeability which causes the characteristic exudates seen on fundoscopy. Pericyte dysfunction predisposes to the formation of microaneurysms. Neovasculization is thought to be caused by the production of growth factors in response to retinal ischaemia.
In exams you are most likely to be asked about the characteristic features of the various stages/types of diabetic retinopathy. Recently a new classification system has been proposed, dividing patients into those with nonproliferative diabetic retinopathy (NPDR) and those with proliferative retinopathy (PDR):
Proliferative retinopathy:
Maculopathy:
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