Ophth! Flashcards
1
Q
What is conjunctivitis?
A
Inflammation of the conjunctiva.
May be bacterial, viral or allergic
2
Q
Presentation of conjunctivitis
A
-red, bloodshot eye
-itchy or gritty sensation
-discharge
3
Q
Presentation of bacterial conjunctivitis vs viral conjunctivitis
A
Bacterial:
-purulent discharge, eyes stuck together in morning
-usually starts in one eye
-highly contagious
Viral:
-clear discharge
-viral symptoms- dry cough, sore throat and blocked nose
-may be tender pre-auricular lymph nodes
-contagious
4
Q
Name causes of acute painful red eye
A
-acute angle- closure glaucoma
-anterior uveitis
-scleritis
-corneal abrasions or ulceration
-keratitis
-foreign body
-traumatic or chemical injury
5
Q
Name causes of acute painless red eye
A
-conjunctivitis
-episcleritis
-subconjunctival haemorrhage
6
Q
What causes neonatal conjunctivitis?
A
Gonococcal infection
-can cause serious complications e.g., permanent vision loss
7
Q
Management for conjunctivitis?
A
-usually resolves within 1-2 weeks without needing treatment
-hygiene measures to reduce spreading
-cleaning the eyes with cooled boiled water and cotton wool to help with discharge
-Chloramphenicol or fusidic acid eye drops are options for bacterial conjunctivitis if necessary
8
Q
What is allergic conjunctivitis and what can help with symptoms?
A
-caused by contact with allergens
-causes swelling of the conjunctival sac and eyelid with itchy and a watery discharge
-antihistamines can help with symptoms
-topical mast-cell stabilisers can help with chronic seasonal symptoms-they work by preventing mast cells from releasing histamine and require several weeks of use before they show benefit
9
Q
Describe blepharitis
A
-inflammation of the eyelid margins
-it causes a gritty, itchy, dry sensation in the eyes
-it can be associated with dysfunction of the Meibomian glands, which are responsible for secreting meibum (oil) onto the surface of the eye
-it can lead to styes and chalazions
10
Q
Describe styes
A
-a style causes a tender red lump along the eyelid that may contain pus
Hordeolum externum is an infection of the glands of Zeis or glands Moll. <- name for external eye stye
Hordeolum internum is infection of the Meibomian glands. They are deeper, tend to be more painful and may point inwards towards the eyeball underneath the eyelid.
-Styes are treated with hot compresses and analgesia.
Topical antibiotics (e.g., chloramphenicol) may be considered if it is associated with conjunctivitis or if symptoms are persistent.
11
Q
What is Chalazion?
A
-A chalazion occurs when a Meibomian gland becomes blocked and swells.
-AKA Meibomian cyst
-Presents with a swelling in the eyelid that is typically not tender
-Treatment is with warm compress and gentle massage towards the eyelashes (to encourage drainage). Rarely, surgical drainage may be required.
11
Q
What is Entropion?
A
Entropion refers to when the eyelid turns inwards with the lashes pressed against the eye.
This causes pain and can result in corneal damage and ulceration.
Initial management is by taping the eyelid down to prevent it from turning inwards.
Definitive management is surgical.
Same day referral to ophthalmology as there is a risk to sight!
Eye drops to prevent eyes from drying out.
12
Q
What is Ectropion?
A
Ectropion refers to when the eyelid turns outwards, exposing the inner aspect.
-usually affects bottom lid
-can result in exposure keratopathy
-regular lubricating drops
13
Q
What is Trichiasis?
A
-Trichiasis refers to inward growth of the eyelashes.
-It results in pain and can cause corneal damage and ulceration.
-Management involves removing the affected eyelashes.
-Recurrent cases may require electrolysis, cryotherapy or laser treatment to prevent them from regrowing.
14
Q
What is periorbital cellulitis?
A
-AKA preseptal cellulitis
-an eyelid and skin infection in front of the orbital septum.
-presents with swollen, red, hot skin around the eyelid and eye.
-treatment is with systemic antibiotics (oral or IV)
-it can develop into orbital cellulitis which is a sight and life-threatening emergency
-a CT scan can be used to distinguish between periorbital and orbital cellulitis
15
Q
What is orbital cellulits?
A
Orbital cellulitis is an infection around the eyeball involving the tissues behind the orbital septum.
Symptoms= pain with eye movement, reduced eye movements, vision changes, abnormal pupil reactions, and proptosis
Emergency admission under ophthalmology and intravenous antibiotics. Surgical drainage may be needed if an abscess forms.
16
Q
What are the most common causes of a sudden painless loss of vision?
A
-ischaemic/vascular -> thrombosis, embolism, temporal arteritis, occlusion of central retinal vein and artery
-vitreous haemorrhage
-retinal detachment
-retinal migraine
17
Q
What are drusen?
A
Extracellular deposits that from beneath the retina
18
Q
What is the most common cause of blindness in adults aged 35-65 years-old?
A
Diabetic retinopathy
19
Q
What is an acute angle closure galucoma?
A
When the iris bulges forward and seals off the trabecular meshwork from the anterior chamber, preventing aqueous humour from draining and leading to a continual increase in intraocular pressure. This pressure builds in the posterior chamber, pushing the iris forward and exacerbating the angle closure.
It is an ophthalmological emergency requiring rapid treatment to prevent permanent vision loss.
20
Q
Risk factors for acute angle-closure glaucoma
A
-increasing age
-FH
-female
-Chinese and East Asian ethnic origin
-shallow anterior chamber
21
Q
Presentation of acute angle-closure glaucoma
A
-severely painful red eye
-blurred vision
-halos around lights
-associated headache, nausea and vomiting
22
Q
Signs on examination in acute angle-closure glaucoma
A
-red eye
-hazy cornea
-decreased visual acuity
-mid-dilated pupil
-fixed-size pupil
-hard eyeball on gentle palpation
23
Q
Management of acute angle-closure glaucoma
A
Initial management:
-lying the patient on their back without a pillow
-Pilocarpine eye drops
-Acetazolamide
-analgesia and an antiemetic, if required
24
What is usually required for definitive treatment?
Laser iridotomy- makes a hole in the iris which allows the aqueous humour to directly from the posterior chamber to the anterior chamber. This relieves the pressure pushing the iris forward against the cornea and opens the pathway for the aqueous humour to drain.
25
What is a glaucoma?
-Glaucoma refers to the optic nerve damage caused by a rise in intraocular pressure. Raised intraocular pressure is caused by a blockage in aqueous trying to escape the eye.
There are 2 types of glaucoma:
-open-angle glaucoma
-acute angle-closure glaucoma
26
What is retinal detachment?
Retinal detachment involves the neurosensory layer of the retina (containing photoreceptors and nerves) separating from the retinal pigment epithelium (the base layer attached to the choroid). This is usually due to a retinal tear, allowing vitreous fluid to get under the neurosensory retina and fill the space between the layers.
The neurosensory retina relies on the blood vessels of the choroid for its blood supply. Therefore, retinal detachment can disrupt the blood supply and cause permanent damage to the photoreceptors, making it sight-threatening.
27
What are the risk factors for retinal detachment?
-lattice degeneration (thinning of the retina)
-posterior vitreous detachment
-trauma
-diabetic retinopathy
-retinal malignancy
-family history
28
Presentation of retinal detachment
-peripheral vision loss (often sudden and described as a shadow coming across the vision)
-blurred or distorted vision
-flashes and floaters
29
Management of retinal tears
-laser therapy
-cryotherapy
30
Management of retinal detachment
-aims to reattach the retina and reduce any traction or pressure that may cause it to detach again
-options are vitrectomy, scleral buckle or pneumatic retinopexy
31
Patients presenting with ... should have a detailed assessment to detect retinal tears and retinal detachment
painless flashes and floaters
32
What does myopia mean?
Short-sightedness
33
What is epiphoria?
Excess tears / watery eyes
34
What are drusen and what are they associated with?
Drusen are associated with dry macular degeneration (the most common type of macular degeneration); these are small yellowish deposits of lipids that accumulate under the retina.
35
What is the definitive treatment for acute angle-closed glaucoma?
Laser peripheral iridotomy is the definitive treatment for acute angle-closure glaucoma
-it involves creating a small hole in the peripheral iris, which allows aqueous humour to flow freely and relieves the blockage causing the angle closure
36
What does scotoma mean?
Scotoma is the medical term for a visual field abnormality, or a blind spot
37
What are cataracts?
Cataracts describe a progressively opaque eye lens, which reduces the light entering the eye and visual acuity.
-cloudy lens!
38
What is the role of the lens? What is it held in place by?
To focus light on the retina.
It is held in place by suspensory ligaments attached to the ciliary body.
The lens has no blood supply and is nourished by the aqueous humour.
39
What is the role of the ciliary body?
The ciliary body contracts and relaxes to change the shape of the lens. When the ciliary body contracts, it releases tension of the suspensory ligaments, and the lens thickens. When the ciliary body relaxes, the suspensory ligaments tension and the lens narrow.
40
How are congenital cataracts screened for?
The red reflex is tested during the neonatal exammination
41
Risk factors for cataracts
-increasing age
-smoking
-alcohol
-diabetes
-steroids
-hypocalcaemia
42
Cataracts presentation
-symptoms are usually asymmetrical
-slow reduction in visual acuity
-progressive blurring of vision
-colours become more faded, brown or yellow
-starbursts can appear around lights, particularly at night
-loss of the red reflex
-lens can appear grey or white using an ophthalmoscope
43
Management of cataracts
-no intervention may be necessary if the symptoms are manageable
-cataract surgery- artificial lens
44
Why may patients still have reduced visual acuity after cataract surgery?
Cataracts can prevent the detection of other pathology, such as macular degeneration or diabetic retinopathy, which can become apparent after surgery.
45
What is endophthalmitis?
Endophthalmitis describes inflammation of the inner contents of the eye, usually caused by infections, and is a rare but serious complication of cataract surgery. It can lead to vision loss. It is treated with intravitreal antibiotics.
46
Where is the anterior chamber of the eye?
Between the cornea and iris
47
Where is the posterior chamber in the eye?
Between the lens and iris
48
The vitreous chamber of the eye is filled with...
vitreous humour
49
What is the normal intraocular pressure of the eye and what creates this pressure?
10-21 mmHg, created by the resistance to flow through the trabecular meshwork
50
Describe aqueous humour
-the aqueous humour supplies nutrients to the cornea
it is produced by the ciliary body
-it flows through the posterior chamber and around the iris to the anterior chamber
-it drains through the trabecular meshwork to the canal of Schlemm at the angle of the cornea and the iris
-from the canal of Schlemm, it eventually enters the general circulation
51
Describe the pathophysiology of an open-angle glaucoma
There is a gradual increase in resistance to flow through the trabecular meshwork. The pressure slowly builds within the eye.
The iris bulges forward and seals off the trabecular meshwork from the anterior chamber, preventing aqueous humour from draining. There is a continual build-up of pressure and an acute onset of symptoms.
It is an ophthalmological emergency.
Raised intraocular pressure causes cupping of the optic disc.
52
Risk factors for open-angle glaucoma
-increasing age
-FH
-black ethnic origin
-myopia (nearsightedness)
53
Presentation of open-angle glaucoma
-glaucoma affects the peripheral vision first, resulting in a gradual onset of peripheral vision loss (tunnel vision)
-fluctuating pain
-headaches
-blurred vision
-halos around lights, particularly at night
54
How can intraocular pressure be measured?
-non-contact tonometry
-Goldmann applanation tonometry
55
What is diagnosis of open-angle glaucoma based on?
-Goldmann applanation tonometry for the intraocular pressure
-slit lamp assessment for the cup-disk ration and optic nerve health
-visual field assessment for peripheral vision loss
-Gonioscopy to assess the angle between the iris and cornea
-central corneal thickness assessment
56
What is the management of open-angle glaucoma?
-treatment is typically started at an intraocular pressure of 24 mmHg or above
-360° selective laser trabeculoplasty - laser improves drainage of trabecular meshwork
-prostaglandin analogue eye drops (e.g., latanoprost) - increases uveoscleral outflow- side effects= eyelash growth, eyelid pigmentation and iris pigmentation (browning)
Other eye drops:
-beta-blockers (e.g., timolol) reduce the production of aqueous humour
-carbonic anhydrase inhibitors (e.g., dorzolamide)- reduce the production of aqueous humour
-sympathomimetics (e.g., brimonidine) reduce the production of aqueous fluid and increase the uveoscleral outflow
-trabeculectomy surgery- involves creating a new channel from the anterior chamber through the sclera to a location under the conjunctiva, causing a bleb on the conjunctiva. From here, it is reabsorbed into the general circulation.
57
Medical term for long-sightedness
Hypermetropia
58
Stereotypical history of scleritis vs episcleritis
Scleritis: a women with a history of rheumatoid arthritis presents with severe, constant pain in her right eye. On examination the right eye is red and there is a degree of photophobia. Visual acuity is normal
Episcleritis: a women with a history of rheumatoid arthritis presents after developing a red right eye. There is no pain, discharge or photophobia although the eye is tearing. Visual acuity is normal.
59
What is blepharitis?
Blepharitis is inflammation of the eyelid margins. It may be due to either meibomian gland dysfunction (common, posterior blepharitis) or seborrhoeic dermatitis/staphylococcal infection (less common, anterior blepharitis).
Blepharitis is also more common in patients with rosacea.
60
Pathophysiology of blepharitis
The meibomian glands secrete oil on to the eye surface to prevent rapid evaporation of the tear film. Any problem affecting the meibomian glands (as in blepharitis) can hence cause drying of the eyes which in turn leads to irritation
61
What are the clinical features of blepharitis?
-symptoms are usually bilateral
-grittiness and discomfort, particularly around the eyelid margins
-eyes may be sticky in the morning
-eyelid margins may be red
-swollen eyelids may be seen in staphylococcal blepharitis
-styes and chalazions are more common in patients with blepharitis
-secondary conjunctivitis may occur
62
Management of blepharitis
-softening of the lid margin using a hot compress twice a day
-lid hygiene- mechanical removal of the debris from lid margins- cotton wool
-artificial tears may be given for symptom relief in people with dry eyes or an abnormal tear film
63
Cause of blepharitis
The exact cause of blepharitis isn't clear. It may be associated with one or more of the following:
-seborrheic dermatitis
-infection
-clogged or malfunction oil glands in your eyelids
-rosacea
-allergies
-eyelash mice or lice
-dry eyes
64
What is anterior uveitis?
Anterior uveitis involves inflammation of the anterior uvea. Intermediate uveitis and posterior uveitis are less common.
An autoimmune process usually causes it, but can be due to infection, trauma, ischaemia or malignancy.
Anterior uveitis involves inflammation in the anterior chamber of the eye. The anterior chamber becomes infiltrated by neutrophils, lymphocytes and macrophages.
Hypopyon refers to fluid collection containing inflammatory cells seen at the bottom of the anterior chamber on inspection.
65
What does the uvea consist of?
Iris
Ciliary body
Choroid
66
What is the choroid?
-part of the uvea
-vascular layer of the eye
-lies between the retina and sclera
67
Anterior uveitis may be associated with an underlying autoimmune condition, particularly:
-seronegative spondyloarthropathies (e.g., ankylosing spondylitis, psoriatic arthritis and reactive arthritis)
-inflammatory bowel disease
-sarcoidosis
-Behcet's disease
68
Presentation and examination findings of anterior uveitis
-painful red eye
-reduced visual acuity
-photophobia (due to ciliary muscle spasm)
-excessive lacrimation
-ciliary flush (a ring of red spreading from the cornea outwards)
-miosis (constricted pupil due to sphincter muscle contraction)
-abnormally shaped pupil due to posterior synechiae (adhesions) pulling the iris into abnormal shapes
-hypopyon (inflammatory cells collected as a white fluid in the anterior chamber)
69
Management of uveitis
-should be referred for urgent assessment and management by an ophthalmologist
first line= steroids (eye drops, oral or IV)
cycloplegics (e.g., cyclopentolate or atropine eye drops)
-recurrent cases may require DMARDs or anti-TNF medications
70
What are Cycloplegics?
Cycloplegics dilate the pupil and reduce pain associated with ciliary spasm .
Cycloplegic refers to paralysing the ciliary muscles.
Cyclopentolate and atropine are antimuscarinic drugs that reduce the action of the iris sphincter muscles and ciliary muscles.
71
What is scleritis?
Scleritis involves inflammation of the sclera.
The sclera is the outer layer of connective tissue surrounding most of the eye (excluding the cornea). It forms the visible white part of the eye.
The most severe type of scleritis is called necrotising scleritis, which can lead to perforation of the sclera.
72
Aetiology of scleritis?
-most cases are idiopathic or associated with an underlying systemic inflammatory condition
-less commonly, it can be due to infection e.g., Pseudomonas or Staphylococcus aureus
-more common in women
-associated conditions= rheumatoid arthritis and vasculitis, particularly granulomatosis with polyangiitis
73
Presentation of scleritis
-red, inflamed sclera
-congested vessels
-severe pain
-pain with eye movement
-photophobia
-epiphora (excessive tear production)
-reduced visual acuity
-tenderness to palpation of the eye
74
Management of scleritis
-urgent assessment by ophthalmologist
-assess for underlying condition e.g rheumatoid arthritis or vasculitis
-NSAIDs oral
-steroids (topical or systemic)
-immunosuppression appropriate to the underlying systemic condition (e.g. methotrexate in rheumatoid arthritis)
-antimicrobial treatment is required for infectious scleritis
75
Optic neuritis is the most common presentation of ...
multiple sclerosis
76
What is optic neuritis?
-demyelination of the optic nerve
-inflammatory condition
77
Clinical features of optic neuritis
-visual loss
-eye pain
-dyschromatopsia
-relative afferent pupillary defect (RAPD) aka Marcus Gunn pupil
-visual field defects
-decreased contrast sensitivity and impaired light adaptation
-Uhthoff's phenomenon-> a transient worsening of visual symptoms with increased body temperature due to exercise, hot showers, or fever- common in optic neuritis
78
What is iritis?
Swelling and irritation of the iris. A type of uveitis. AKA anterior uveitis
79
Causes of iritis
Systemic autoimmune disorders:
Seronegative spondyloarthropathies (ankylosing spondylitis, juvenile RA, Reiter’s syndrome, IBD)
Behçet’s disease
Sarcoidosis
Psoriatic arthropathy
Multiple sclerosis
Infections (herpes simplex, herpes zoster, cytomegalovirus, toxoplasmosis commonly; histoplasmosis, lyme’s disease, syphilis, toxocariasis, TB less commonly; aspergillus and candida rarely)
Trauma
Neoplasia
80
Presentation of iritis
-pain and dull ache
-red eye
-diminished or blurry vision
-watery eye
-photophobia (ciliary spasm)
-flashes and floaters
-unreactive or irregular pupil
-ciliary flush (red ring around the cornea)
-miosis (sphincter muscle contraction)
-hypopyon (inflammatory cells collected as white fluid builds up in the anterior chamber)
81
Treatment of iritis
-steroids
-cycloplegics e.g. cyclopentolate or atropine eye drops
82
What is age related macular degeneration?
Age-related macular degeneration (AMD) is a progressive condition affecting the macula.
It is the most common cause of blindness in the UK.
It is often unilateral but may be bilateral.
83
What are the 2 types of age related macular degeneration?
-Wet (also called neovascular) - 10% of cases
-Dry (also called non-neovascular) - 90% of cases
84
What is the macula?
The macula is found in the centre of the retina.
It generates high-definition colour vision in the central visual field.
4 layers:
-Choroid layer (contains the blood vessels that supply the macula)
-Bruch's membrane
-Retinal pigment epithelium
-Photoreceptors
85
What are drusen and what are they an important finding in?
Drusen are an important finding with AMD. Drusen are yellowish deposits of proteins and lipids between the retinal pigment epithelium and Bruch's membrane. A few small drusen can be an early sign of macular degeneration.
86
What are features that are common to wet and dry AMD?
-drusen
-atrophy of the retinal pigment epithelium
-degeneration of the photoreceptors
87
Describe the new vessel growth in wet AMD
In wet AMD, new vessels develop from the choroid layer and grow into the retina (neovascularisation). These vessels can leak fluid or blood causing oedema and faster vision loss. A key chemical that stimulates the development of new vessels is vascular endothelial growth factor (VEGF). This is the target of medications to treat wet AMD.
88
Risk fators
-older age
-smoking
-family history
-cardiovascular disease (e.g., hypertension)
-obesity
-poor diet (low in vitamins and high in fat)
89
Presentation of age-related macular degeneration
Visual changes associated with AMD tend to be unilateral, with:
-gradual loss of central vision
-reduced visual acuity
-crooked or wavy appearance to straight lines (metamorphopsia)
-gradually worsening ability to read small text
90
Examination findings of age-related macular degeneration
-reduced visual acuity using a Snellen chart
-Scotoma (an enlarged central area of vision loss)
-Amsler gird test can be used to assess for the distortion of straight lines seen in AMD
-Drusen may be seen during fundoscopy
91
What does the slit lamp examination give a detailed view of?
Retina and macula
92
Optical coherence tomography gives a cross-sectional view of...
the layers of the retina and is used for diagnosing and monitoring AMD
93
Fluorescein angiography involves...
giving a fluorescein contrast and photographing the retina to assess the blood supply, showing oedema and neovascularisation in wet AMD
94
Management of age-related macular degeneration
-no specific treatment for dry AMD- management involves monitoring and reducing the risk of progression by avoiding smoking, controlling BP, vitamin supplementation
-Anti-VEGF medications are used to treat wet AMD.
Vascular endothelial growth factor (VEGF) stimulates the development of new blood vessels in the retina.
Anti-VEGF medications (e.g., ranibizumab, aflibercept and bevacizumab) block VEGF and slow the development of new vessels. They are injected directly into the vitreous chamber of the eye (intravitreal), usually about once a month.
95
What is keratitis?
Keratitis refers to inflammation of the cornea
96
Causes of keratitis
-viral infection - HSV
-bacterial infection- Pseudomonas or Staphylococcus
-fungal infection - Candida or aspergillus
-contact lens-induced acute red eye (CLARE)
-exposure keratitis, caused by inadequate eyelid coverage (e.g. ectropion)
97
Describe herpes simplex keratitis
Herpes simplex virus infection is the most common cause of keratitis and is called herpes simplex keratitis. HSV can cause inflammation in any part of the eye but most commonly affects the epithelial layer of the cornea.
Herpes simplex keratitis can be primary or recurrent. Recurrence is caused by the virus travelling to the trigeminal ganglion, where it becomes latent (dormant) and can reactivate later.
Herpes simplex keratitis usually affects only the epithelial layer of the cornea. Inflammation of the stroma (the layer between the epithelium and endothelium) is called stromal keratitis. This is associated with complications such as stromal necrosis, vascularisation and scarring an can lead to corneal blindless.
98
Presentation of herpes simplex keratitis
-primary infection often involves mild symptoms of blepharoconjunctivitis (inflammation of the eyelid margins and conjunctiva)
recurrent infection may present with:
-painful red eye, photophobia, vesicles (fluid-filled blisters), foreign body sensation, watery discharge, reduced visual acuity
-Slit lamp examination- fluorescein staining shows a dendritic corneal ulcer. Dendritic describes the branching appearance of the ulcer.
99
Corneal scrapings can be for ... testing of keratitis
viral
100
Management of herpes simplex keratitis
-referred for urgent assessment by an ophthalmologist
-topical or oral antivirals (e.g aciclovir or ganciclovir)
-corneal transplant is an option to treat permanent scarring and vision loss after keratitis
101
Describe retinal vein occlusion
Retinal vein occlusion occurs when a blood clot (thrombus) forms in the retinal veins, blocking the drainage of blood from the retina. The thrombus may form in the central retinal vein or branch retinal veins.
Blockage of a retinal vein causes venous congestion in the retina. Increased pressure in the retinal veins results in fluid and blood leaking into the retina, causing macular oedema and retinal haemorrhages. This results in retinal damage and vision loss.
Retinal vein occlusion can be categorised as ischaemic or non-ischaemic. Retinal ischaemia leads to the release of vascular endothelial growth factor (VEGF), resulting in new blood vessel development (neovascualrisation)
102
What are the risk factors for retinal vein occlusion?
-hypertension
-high cholesterol
-diabetes
-smoking
-high plasma viscosity (e.g., myeloma)
-myeloproliferative disorders
-inflammatory conditions (e.g. SLE)
103
Presentation of retinal vein occlusion
-painless blurred vision or vision loss
-In branch retinal vein occlusion, the vision loss corresponds to the affected area of the retina. When it involves the branch draining the macula, central vision is lost.
Fundoscopy findings:
-dilated tortuous retinal veins
-flame and blot haemorrhages
-retinal oedema
-cotton wool spots
-hard exudates
104
Management of retinal vein occlusion
-immediate referral to ophth
-treat macular oedema and prevent neovascularisation
-Anti-VEGF therapies (e.g., ranibizumab and aflibercept)
-Dexamethasone intraviral implant (to treat macular oedema)
-laser photocoagulation (to treat new vessels)
105
Describe central retinal artery occlusion
Central retinal artery occlusion occurs due to obstruction to blood flow through the central retinal artery. The central retinal artery is a branch of the ophthalmic artery, which is a branch of the internal carotid artery.
106
Causes of central retinal artery occlusion
-most common cause is atherosclerosis
-giant cell arteritis, where vasculitis affecting the ophthalmic or central retinal artery reduces blood flow
107
risk factors for central retinal artery occlusion
-risk factors for cardiovascular disease (e.g., smoking, hypertension, diabetes and raised cholesterol) increase the risk of atherosclerosis causing central retinal artery occlusion
-risk factors for giant cell arteritis are white ethnicity, older age, female and polymyalgia rheumatica
108
Presentation of central retinal artery occlusion
-sudden painless loss of vision- "curtain coming down"
-relative afferent pupil defect- the input is not sensed by the ischaemic retina when testing the direct light reflex but is sensed during the consensual light reflex
-fundoscopy will show a pale retina with a cherry spot red- the retina is pale due to a lack of perfusion- the cherry red spot is the fovea
109
What are the key differentials for a sudden painless vision loss?
-retinal detachment
-central retinal artery occlusion
-central retinal vein occlusion
-vitreous haemorrhage (due to diabetic retinopathy)
110
What does amaurosis fugax mean?
Amaurosis fugax describes a temporary loss of vision caused by a temporary interruption to the blood supply
111
Management for central retinal artery occlusion
-vision-threatening emergency
-giant cell arteritis is a potentially reversible cause- testing includes an ESR blood test and temporal artery biopsy- treatment is with high-dose systemic steroids
-ocular massage
-anterior chamber paracentesis (removing fluid from the anterior chamber to reduce the intraocular pressure)
-inhaled carbogen (5% carbon dioxide and 95% oxygen) (to dilate the artery)
-Sublingual isosorbide dinitrate (to dilate the artery)
-oral pentoxifyline (to dilate artery)
-IV acetazolamide and mannitol to reduce intraocular pressure and also topical timolol
112
acute glaucoma vs chronic glaucoma
People with chronic glaucoma may not even notice vision loss for years, and they may never experience discomfort. Those with acute forms of the disease can develop significant pain, nausea, and vision changes.
113
What is amblyopia?
-failure of the brain to process information from the eye so vision is poor in one eye
-eye structurally normal-causes anything that focusing issues: squint, refractive error, occlusion
114
Name some systemic problems that may affect the vision
-polymyalgia
-GCA
-hypertension
-high cholesterol
-DM
115
What investigations should be performed in patients with suspected acute angle closure glaucoma?
-Tonometry -> assesses IOP
-Gonioscopy -> a special lens for the slit lamp that allows for visualisation of the angle
116
What does mydriatic (cycloplegic) mean?
A drug that causes the pupil to dilate
117
