Ophthalmology - Loss of Vision Flashcards
Do cataracts cause sudden or gradual loss of vision?
Gradual
What are cataracts?
The lens in the eye becomes cloudy and opaque due to denatured protein.
What is the job of the lens?
Job of lens is to focus light coming onto the eye at the retina at the back of the eye.
What % of >65s have evidence of cataracts?
75%
Describe the vision loss in cataracts
- Very slow reduction in vision
- Progressive blurring/clouding of vision
- Difficulties due to glare from bright lights (‘starbursts’) – ‘haloes’ around lights
What condition may ‘haloes’ around lights indicate?
Cataracts or glaucoma
What may patients who see ‘haloes’ around lights complain of?
May complain of difficulty driving at night
Cataracts can rarely present in children. How may they be picked up in children?
- May simply present as a squint
- May be an incidental finding of leukocoria (reflection of white light)
What is leukocoria?
Leukocoria means “white pupil’ and it refers to the reflection of white light seen upon direct illumination of the fundus through the pupil, in contrast to the usual red glow.
How can cataracts be screened for during the neonatal exam?
Can be screened for using the red reflex during neonatal examination
Risk factors for cataracts?
- Age
- Smoking
- Diabetes
- Alcohol
- Sunlight exposure
- Corticosteroid use
- Trauma
- Previous eye surgery
What is the management for cataracts?
Surgery
What does cataracts surgery involve?
- Removing the lens that has developed a cataract and replacing it with an artificial lens (pseudophakia)
- Done using US waves (phacoemulsification) → done under topical anaesthetic
What is glaucoma?
Glaucoma refers to the optic nerve damage that is caused by a significant rise in intraocular pressure. This rise in IOP is caused by a blockage in aqueous humour trying to escape the eye.
What are the 2 types of glaucoma?
- Open angle
- Closed angle
Do chronic open angle glaucoma present with sudden or gradual vision loss?
Gradual
What is chronic open angle glaucioma?
Chronic open angle glaucoma refers to optic neuropathy with death of optic nerve fibres, with or without raised IOP.
What aspect of the vision is affected in chronic open angle glaucoma?
- Affects peripheral vision first until ‘tunnel vision’ is eventually experienced
- Patient may complain of knocking into objects or having to dodge cars when crossing roads
Give some other symptoms of chronic open angle glaucoma
Gradual onset of fluctuating pain, headaches, blurred vision and halos around lights (particularly at nighttime)
What may be seen in fundoscopy in chronic open angle glaucoma?
Optic disc cupping
What is optic disc cupping?
Optic disc cupping refers to the cup appearing to become larger over time, often due to fibres in the optic nerve dying. As the structural support for the optic disc is no longer there, the cup seems larger.
Which investigation is used to measure the intraocular pressure?
Tonometry
What will be seen in a visual field assessment in glaucoma?
Peripheral vision loss
What are the 4 pharmacological agents used in chronic open angle glaucoma?
- Topical beta blocker e.g. timolol → reduce aqueous production
- Prostaglandin analogue eye drops e.g. latanoprost → increase uveoscleral outflow
- Carbonic anhydrase inhibitors (e.g. Dorzolamide) → reduce aqueous production
- Miotics (e.g. pilocarpine) → increase uveoscleral outflow
What is the function of topical beta blockers in glaucoma?
reduce aqueous production
What is the function of prostaglandin analogue eye drops in glaucoma?
Increase uveoscleral outflow
Give an example of a prostaglandin analogue eye drop
Latanoprost
Give an example of a topical beta blocker
Timolol
What is the function of carbonic anhydrase inhibitors in glaucoma?
Reduce aqueous production
What is the function of miotics in glaucoma?
Increase uveoscleral outflow
Give an example of a miotic used in glaucoma
Pilocarpine
Give an example of a carbonic anhydrase inhibitor used in glaucoma
Dorzolamide
What are the 2 main complications of glaucoma?
- Optic neuropathy
- Optic atrophy
What is optic atrophy?
Optic atrophy refers to the death of the retinal ganglion cell axons that comprise the optic nerve with the resulting picture of a pale optic nerve on fundoscopy.
How would optic atrophy present on fundoscopy?
A pale optic nerve/disc
How would optic atrophy affect vision?
irreversible loss of visual acuity
What is the most common cause of blindness in the UK?
Age related macular degeneration (ARMD)
What is ARMD?
Degeneration in the macula that causes a progressive deterioration in vision.
What is the macula?
Part of the retina at the back of the eye that is responsible for central vision, most of colour vision and the fine detail of what we see. The macula has a very high concentration of photoreceptor cells – the cells that detect light.
What are the 2 types of ARMD?
- Wet (10% cases) → worse prognosis
- Dry (90% cases)
Risk factors for ARMD?
- Age
- Smoking
- White or Chinese ethnicity
- FH
- CVS disease
Does ARMD present with a gradual or sudden loss of vision?
Gradual
Describe the vision loss in dry ARMD
- Progressive, gradual loss of central vision over years/decades
- Typically complain of difficulty reading text, recognising faces and problems with vision in dim light – reduced visual acuity
- Visual fluctuation is classic presentation – day by day vision may appear to deteriorate and improve unpredictably
What is seen in fundoscopy in dry ARMD?
Drusen
What are drusen? Are they normal?
Drusen are small, yellowish deposits of cellular debris (protein + lipids) that accumulate under the retina
- Small drusen are normal
- Larger and greater numbers of drusen can be an early sign of macular degeneration (common to both wet and dry)
Describe the vision loss in wet ARMD
- Progressive loss of central vision over months
- Visual fluctuation
- Difficulty reading text, recognising faces and seeing in dim light
What is seen in fundoscopy in wet ARMD?
- Drusen
- Macular oedema
What is a scotoma?
a central patch of vision loss
Results of a snellen chart investigation in ARMD?
reduced visual acuity due to degeneration of macula (& photoreceptors)
Management of dry ARMD?
- Stop smoking
- Control blood pressure
- Vitamins
What pharmacological agent can be used in the management of wet ARMD?
Anti-VEGF medications e.g. ranibizumab, bevacizumab, pegaptanib
What are anti-VEGF medications?
Anti-VEGF treatments are a group of medicines which reduce new blood vessel growth (neovascularisation) or oedema.
What is hypermetropia/hyperopia?
Long-sightedness i.e. distant objects are seen clearly but near objects appear blurred.
What is the cause of hypermetropia?
Eyeball is too short, or cornea is too flat. Light is focused behind (instead of on) the retina due to insufficient accommodation by the lens.
How may hypermetropia present?
- Squint (strabismus)
- Amblyopia (lazy eye) – if hypermetropia present from young age
If hypermetropia present from young age, what can it cause?
Amblyopia (lazy eye)
What is hyopia?
Short-sightedness i.e. can see objects near to you clearly but objects farther away are blurry.
What is the cause of myopia?
Eyeball is too long,** or cornea is too **curved. Shape of eye causes light to be refracted incorrectly, focusing images in front of your retina instead of on your retina.
How is light focused in hypermetropia?
Behind the retina
How is light focused in myopia?
In front of the retina
Complications of myopia?
- Retinal detachment
- Cataracts
- Open angle glaucoma
- Posterior vitreous detachment
Is myopia generally diagnosed in children or adults?
Children
What is presbyopia?
Gradual loss of eye’s ability to focus on near objects.
What is the cause of presbyopia?
Hardening of lens which occurs with ageing. Lens becomes less flexible so cannot change shape to focus on close-up images, so they appear out of focus.
What are the 4 important questions to ask in acute vision loss?
- What is the time course?
- What are the associated symptoms?
- What is the medical history?
- What does the retina look like?
Give some painless causes of acute/subacute vision loss
- Retinal detachment
- Giant cell arteritis
- Amaurosis fugax – this is only transient
- Stroke affecting visual pathways
- Retinal vein or artery occlusion
- Vitreous haemorrhage
- Posterior vitreous detachment
- Wet age-related macular degeneration
Give some painful causes of acute/subacute vision loss
- Acute angle closure glaucoma
- Optic neuritis
- Uveitis
- Keratitis
- Endophthalmitis
Give 3 causes of transient vision loss (lasts <24 hours)
- Migraine
- Amaurosis fugax
- Papilloedema
Describe the vision loss in a migraine
- Marching, sparkling, shimmering lights
- <60 minutes
- Both eyes but typically only one hemifield
What is amaurosis fugax?
‘Transient darkening’ and it is used to describe a temporary loss of vision through one eye, which returns to normal afterwards.
Cause → This is usually due to a temporary disturbance of the blood flow to the back of the eye.
How does a papilloedema affect vision?
- Complete brief loss of vision
- May be unilateral or bilateral
Give some causes of a persistent loss of vision (>24 hours)
- Cataract
- Refractive error
- Dry age-related macular degeneration (AMD)
- Open-angle glaucoma
- Tumours affecting visual pathway
- Nutritional optic neuropathy
What is giant cell arteritis/temporal arteritis?
Most common form of arteritic anterior ischaemic optic neuropathy. Systemic vasculitis of the medium and large arteries (i.e. inflammation of arteries).
Who does giant cell arteritis typically affect?
Typically elderly female
Describe the vision loss seen in giant cell arteritis
Sudden onset painless loss of vision with headache, jaw claudication and scalp tenderness
What other symptoms are seen in giant cell arteritis?
Headache, jaw claudication and scalp tenderness
What condition is giant cell arteritis strongly associated with?
Polymyalgia rheumatica
What is polymyalgia rheumatica?
Polymyalgia rheumatica is an inflammatory disorder that causes muscle pain and stiffness, especially in the shoulders and hips. Signs and symptoms usually begin quickly and are worse in the morning.
What is the management of giant cell arteritis?
High dose steroids → prednisolone
What occurs in retinal detachment?
Where the retina separates from the choroid underneath.
What is the cause of retinal detachment?
Usually due to a retinal tear that allows vitreous fluid to get under the retina and fill the space between the retina and choroid.
What are the risk factors for retinal detachment?
- Posterior vitreous detachment
- Diabetic retinopathy
- Trauma
- Retinal malignancy
- Older age
- FH
Describe the vision loss in retinal detachment
Painless sudden loss of vision
how would a patient typically describe their vision loss in retinal detachment?
Flashes and floaters’** followed by a ‘**curtain falling over’ their vision
Retinal detachment fundoscopy:
How does the presentation of retinal detachment differ from amaurosis fugax?
Amaurosis fugax is transient
Management of retinal detachment?
- Laser therapy
- Cryotherapy
What causes amaurosis fugax?
Lack of blood supply to retina e.g. plaque or blood clot in carotid artery.
Risk factors for amaurosis fugax
- PMH of heart disease
- HTN
- High cholesterol
- Smoking
- Alcohol
- Cocaine abuse
Describe the vision loss in amaurosis fugax
- Painless sudden loss of vision (one or both eyes)
- TEMPORARY
What occurs in posterior vitreous detachment?
Vitreous gel within the eye separates from the retina. This gel is important in maintaining the structure of the eyeball and keeping the retina pressed on the choroid.
Who is posterior vitreous detachment common in?
Older patients
Give some causes of posterior vitreous detachment
- Eye trauma
- Old age (normal part of aging)
- Severe myopia – also known as nearsightedness
Describe the presentation of posterior vitreous detachment
- Similar to retinal detachment fundoscopy is key in diagnosing
- Painless loss of vision
- Floaters
- Flashing lights (photopsia)
Management of posterior vitreous detachment?
None necessary – symptoms improve as brain adjusts
What is a vitreous haemorrhage?
Bleeding into vitreous humour.
Presentation of a vitreous haemorrhage?
- Mild – floaters
- Severe:
- Painless sudden loss of vision
- Retina difficult to view on fundoscopy
Describe the vision loss in vitreous haemorrhage
Painless sudden loss of vision
What is the most common cause of vitreous haemorrhage?
Diabetic retinopathy
Give some risk factors for vitreous haemorrhage
- Diabetic retinopathy – most common cause
- Retinal tear or detachment
- Posterior vitreous detachment
What is retinal artery occlusion?
Block of blood flow through the central retinal vein that supplies blood to the retina. It is a branch of the ophthalmic artery which is a branch of the internal carotid artery.
What is the retinal artery a branch of?
It is a branch of the ophthalmic artery which is a branch of the internal carotid artery.
Is retinal artery or central retinal vein occlusion more common?
Central retinal vein occlusion
What is the most common cause of retinal artery occlusion?
Atherosclerosis
Give 2 causes of retinal artery occlusion
- Atherosclerosis
- Giant cell arteritis
WHow can giant cell arteritis cause retinal artery occlusion?
Vasculitis affecting ophthalmic or central vein artery causes reduced blood flow
What are the risk factors for retinal artery occlusion?
Same as CVS disease
Describe the vision loss in retinal artery occlusion
Sudden painless loss of vision
Describe the vision loss in retinal artery vs central vein occlusion
Retinal artery occlusion typically occurs more rapidly than CRVO
Describe fundoscopy results in retinal artery occlusion
pale retina (as blood can’t get to it) with cherry red spot at macula
What occurs in retinal vein occlusion
Blood clot (thrombus) forms in the retinal veins and blocks the drainage of blood from the retina. The central retinal vein runs through the optic nerve and is responsible for draining blood from the retina.
Describe the vision loss in retinal vein occlusion
Sudden painless loss of vision
Describe fundoscopy results in retinal vein occlusion
- ‘Stormy-sunset’ appearance
- Flame and blot haemorrhages (blood can’t get out
Risk factors for retinal vein occlusion?
- Old age
- HTN
- Diabetes mellitus
- Polycythaemia
- Arteriosclerosis
What condition is optic neuritis typically associated with?
Multiple sclerosis
Describe the visual problems in optic neuritis
-
Vision loss typically progresses over hours to days (not ‘sudden’ loss of vision)
- Central scotoma – enlarged blind spot
- Impaired colour vision
- Relative afferent pupillary defect
- Painful
- Pain on ocular movement
- ‘Red desaturation’
Is optic neuritis painful?
Yes
Does optic neuritis affect colour vision?
Yes
Amaurosis fugax vs central retinal artery occlusion?
Both cause vision loss due to lack of blood supply.
CRAO is a medical emergency that may result in irreversible loss of vision → permanent
Amaurosis fugax or “transient CRAO” → transient.