Loss of Vision and Ophthalmic Emergencies Flashcards
If loss of vision is painful what structures are likely to be involved?
Anterior of the eye is associated with painful loss of vision- these structures have a rich innervation
Iris, cornea, sclera
If loss of vision is painful what structures should be considered?
Posterior components of the eye-
Lens, Vitreous, Retina
Note- optic neuritis can cause pain of movement of the eye due to inflammation of the nerve
If vision loss is sudden what sort of causes should you consider?
Vascular causes are acute onset
If someone presents with loss of history what should you ask about?
When did this happen?
Painful
Painless
How quickly did this come on? Was it sudden?
How is your vision at the moment?
Has the loss been permanent since onset or has it been transient?
Have you lost central vision or peripheral vision?- Struggling to read or bumping into things
One of both eyes affected?- Processes such as diabetic retinopathy cause bilateral damage
Any other associated symptoms? E.g. Headache, polydipsia, polyuria
When a patient presents with loss of vision what should always be checked?
Check Visual Acuity- Could be OSCE so learn this
What is an RAPD?
It is a sign of an optic nerve lesion. There is consensual reflex but no direct as there has been loss of sensory input to the affected side. Therefore appears to dilate when the light is shone into the affected eye.
If someone presents with painless loss of vision which part of the eye is likely to be affected?
Structures from the lens backwards- back of the eye
Except for optic neuritis which causes pain on eye movement
If loss of vision is sudden what causes should you consider?
Vascular causes:
Retinal Vein Occlusion
Retinal Artery Occlusion
May affect central retinal vessels or branches of the vessels
How are vessel arcades spilt in the eye?
Superior or inferior
Nasal or Temporal
What do you see on fundoscopy with a branch retinal vein occlusion?
Haemorrhages confined to the affected area
What do you see with a central retinal vein occlusion?
Fairly severe picture
Wide spread haemorrhages throughout the retina
Swollen disc
What do you see with a branch retinal arteriolar occlusion?
Pallor of the retina in the area supplied by the vessel- it looks less pink than the surrounding area
May be able to see embolic area in the vessel- pale
What are the most common causes of branch arteriolar occlusion?
Emboli- often either cardiac or carotid source
What do you see on fundoscopy with a central retinal artery occlusion?
Pallor of the entire retina
Cherry red spot at the macula
Aim to treat within 8 hours- IV acetazolamide, ocular massage, re-breath into paper bag, anterior chamber paracentesis, refer to stroke/TIA clinic
What are some causes of sudden painless loss of vision?
Central Retinal Artery or Vein Occlusion
Anterior Ischaemic Optic Neuropathy (arteritis or non arteritic (embolic))
Retinal detachement
Vitreous Haemorrhage
What is anterior ischaemic optic neuropathy?
Ischaemia to the anterior optic nerve and optic disc
What are the two categories of causes for anterior ischaemic optic neuropathy?
Arteritic- GCA/Temporal Arteritis
Non Arteritic- Embolic (Cardiac or Carotid source)
What are the features of anterior ischaemic optic neuropathy seen on fundoscopy?
Pallor of the optic disc
Blurring of the edges of the optic disc (loss of sharp border)
Often also have altitudinal visual field defect
What must be ruled out in patients with anterior ischaemic optic neuropathy? How might this be done?
Giant cell arteritis
History of headaches, scalp tenderness, pain when brushing hair, fatigue, lethargy. Bloods- raised ESR and CRP
What is a leading cause of vitreous haemorrhage?
Proliferative diabetic retinopathy causes fragile vessels to form which are prone to bleeding, these can then bleed into the vitreous humour.
Bleeding causes a disruption of clear optical media and so there is vision loss.
Why is an increase in the number of floaters more concerning for a diabetic patient?
Could be a sign of bleeding vessels, causing vitreous haemorrhage. These need to be checked out.
Fragile vessels for due to proliferative diabetic retinopathy.
Describe the process that can cause retinal detachment?
PVD can pull on the retina and cause retinal tears. Fluid can then track underneath the retina leading to retinal detachment.
What are the symptoms of retinal detachment?
Flashes and Floaters (sx of PVD)
Loss of vision, central vision is lost if the macula becomes involved.
What are some causes of retinal detachment?
PVD- Causing retinal tear and fluid tracks underneath the tear
Myopia- Longer eye ball means there is a thinner retina more prone to breaking
Trauma- stretching and compressing of the globe occurs with blunt trauma that can cause tears and detachment