opthalmology Flashcards
what sort of conditions lead to sudden loss of vision?
vascular occlusions:
- branch and central retinal artery occlusions
- branch and central retinal vein occlusions
- anterior ischaemic optic neuropathy
inflammatory disorders
- optic neuritis (MS or secondary)
retinal detachment
what will patients who have retinal artery occlusion have?
patients will present with sudden, loss of vision (central retinal artery occlusion) or altitudinal loss (branch retinal artery occlusion)
they have a relative afferent pupillary defect
usually it is caused by atherosclerosis or emboli from the carotid or the heart
less frequently it can be caused by giant cell arteritis
vision can not be improved
management is directed to secondary prevention of myocardial or cerebrovascular events e.g.prescribe Aspirin
what is transient monocular visual loss?
often referred to amaurosis fugax or TIA
patient describes curtain coming over vision
lasts around 30 minutes
resolves completely
investigate for TIA
manage with aspirin, clopidogrel etc
what is conjunctivitis?
inflammation of the conjunctiva - this is a thin membrane that covers the front surface of the eye and the inner surface of the eye lids.
what are the different types of conjunctivitis?
bacterial
viral
allergic
how does conjunctivitis present?
can be unilateral or bilateral red eyes blood shot itchy or gritty sensation discharge from the eye
how would bacterial and viral conjunctivitis present?
bacterial conjunctivitis presents with a purulent discharge and an inflamed conjunctiva. It is typically worse in the morning when the eyes may be stuck together, it usually starts in one eye and then can spread to the other because it is highly contagious.
viral conjunctivitis is common and usually presents with a clear discharge. It is often associated with other symptoms of a viral infection such a dry cough, sore throat and blocked nose. There may be tender preauricular lymph nodes (in front of the ears)
what are the differential diagnosis for acute painless red eye?
conjunctivitis
episcleritis
subconjunctival haemorrhage
what are the differential diagnosis for a painful acute red eye?
Glaucoma Anterior uveitis Scleritis Corneal abrasions or ulceration Keratitis Foreign body Traumatic or chemical injury
how do you manage conjunctivitis?
often resolves without treatment after 1-2 weeks
advise on good hygiene to avoid spreading (avoid sharing towels or rubbing eyes and regularly wash hands) and avoid use of contact lenses. Cleaning the eyes with cooled boiled water and cotton wool can help clear the dischargee
Bacteriral: antibiotic eye drops can be considered - Chloramphenicol and fuscidic acid eye drops are both options
if under one month of age they need an urgent ophthalmology review
what is allergic conjunctivitis?
what can be used to treat it?
it is caused by contact with allergens - it causes swelling of the conjunctival sec and eye lid with a significant watery discharge and itch
antihistamines - oral or topical can be used to reduce symptoms
2nd line - topical mast-cell stabilisers e.g. sodium cromoglicate and nedocromil
what are glaucomas?
there is optic nerve damage that is caused by a significant rise intraocular pressure. The raised intraocular pressure is caused by a blockage aqueous humour trying to escape the eye.
There are two types of glaucoma - open angle and closed angle
what happens in open angle glaucoma?
In open angle glaucoma, there is a gradual increase in resistance through the trabecular meshwork. This makes it more difficult for aqueous humour to flow through the meshwork and exit the eye. Therefore the pressure slowly builds within the eye and this gives a slow and chronic onset of glaucoma.
there is a large angle between iris and cornea
what happens in acute closure glaucoma?
In acute angle closure glaucoma the iris bulges forward and seals off the trabecular meshwork from the anterior chamber preventing aqueous humour from being able to drain away. This leads to a continual build up of pressure. This is an ophthalmology emergency
what are the risk factors for open angle glaucoma?
increasing age family history black ethnic origin Nearsightedness (myopia) DM corticosteroids
how does open angle glaucoma present?
Often the rise in intraocular pressure is asymptomatic for a long period of time. It is diagnosed by routine screening when attending optometry for an eye check.
the glaucoma will affect the peripheral vision first. Gradually the peripheral vision closes in until the experience tunnel vision
they will get optic disc cupping
what signs would you see on fundoscopy in open angle glaucoma?
- Optic disc cupping - cup-to-disc ratio >0.7 (normal = 0.4-0.7), occurs as loss of disc substance makes optic cup widen and deepen
- Optic disc pallor - indicating optic atrophy
- Bayonetting of vessels - vessels have breaks as they disappear into the deep cup and re-appear at the base
- Additional features - Cup notching (usually inferior where vessels enter disc), Disc haemorrhages
what investigations would you perform for open angle glaucoma?
tonometry (will show elevated intra-ocular pressure)
ophthalmoscopy/fundoscopy to check the optic disc for cupping and optic nerve health
visual field testing
slit lamp biomicroscopy
how do you manage open angle glaucoma
first line
- topical ophthalmic prostaglandin analogues (latanoprost) - increases outflow
second line
- topical ophthalmic beta blockers (timolol) - decreases production
- topical ophthalmic carbonic anhydrase inhibitors
- topical ophthalmic alpha-2 adrenergic agonists - brimonidone
eye drop failure :
laser trabeculoplasty
surgical interventoin
what can be used to measure intraocular pressure?
Non-contact tonometry is the commonly used machine for estimating intraocular pressure by opticians. It involves shooting a “puff of air” at the cornea and measuring the corneal response to that air. It is less accurate but gives a helpful estimate for general screening purposes.
Goldmann applanation tonometry is the gold standard way to measure intraocular pressure. This involves a special device mounted on a slip lamp that makes contact with the cornea and applies different pressures to the front of the cornea to get an accurate measurement of what the intraocular pressure is.
what are the risk factors for acute closed angle glaucoma?
increasing age female are affected around 4 time more often than males family history Chinese and east asian ethnic origin. shallow anterior chamber
what medications may precipitate acute angle closure glaucoma?
Adrenergic medications such as noradrenalin
Anticholinergic medications such as oxybutynin and solifenacin
Tricyclic antidepressants such as amitriptyline, which have anticholinergic effects
how will acute angle closure glaucoma present?
the patient will generally appear unwell in themselves
they have short history of
- severely painful eye
- blurred vision
- halos around lights
- associated headache, nausea and vomiting
what would you see when examining a patient with acute angle closure glaucoma ?
Red eye Teary Hazy cornea Decreased visual acuity Dilatation of the affected pupil Fixed pupil size Firm eyeball on palpation
what investigations are performed for angle-closure glaucoma?
gonioscopy - examination of the anterior chamber angle is the definitive test for diagnosing angle-closure glaucoma
slit lamp examination can also be performed
automatic static perimetry
how is acute closed angle glaucoma managed?
NICE CKS 2019 states that patients with potentially life threatening causes of red eye should be referred for same day assessment by an ophthalmologist.
lie patient on their back without a pillow
give pilocarpine eye drops (2% for blue, 4% for brown)
give acetazolamide 500mg orally
give analgesia and antiemetic if required
Laser iridotomy is usually required as a definitive treatment. This involve using a laser to make a hole in the iris to allow the aqueous humour to flow from the posterior chamber into the anterior chamber. The relieves pressure that was pushing the iris against the cornea and allows the humour the drain.
why are pilocarpine and acetazolamde given in acute angle closure glaucoma?
Pilocarpine acts on the muscarinic receptors in the sphincter muscles in the iris and causes constriction of the pupil. Therefore it is a miotic agent. It also causes ciliary muscle contraction. These two effects cause the pathway for the flow of aqueous humour from the ciliary body, around the iris and into the trabecular meshwork to open up.
Acetazolamide is a carbonic anhydrase inhibitor. This reduces the production of aqueous humour.
what is anterior uveitis?
aka iritis
Anterior uveitis is inflammation in the anterior part of the uvea. The uvea involves the iris, ciliary body and choroid. The choroid is the layer between the retina and the sclera all the way around the eye. Sometimes anterior uveitis is referred to as iritis.
It involves inflammation and immune cells in the anterior chamber of the eye. The anterior chamber of the eye becomes infiltrated by neutrophils, lymphocytes and macrophages. This is usually caused by an autoimmune process but can be due to infection, trauma, ischaemia or malignancy. Inflammatory cells in the anterior chamber cause floaters in the patient’s vision.
Anterior uveitis can be acute or chronic. Chronic anterior uveitis is more granulomatous (has more macrophages) and has a less severe and longer duration of symptoms, lasting more than 3 months.
what is acute and chronic anterior uveitis associated with?
Acute anterior uveitis is associated with HLA B27 related conditions:
Ankylosing spondylitis
Inflammatory bowel disease
Reactive arthritis
Chronic anterior uveitis is associated with: Sarcoidosis Syphilis Lyme disease Tuberculosis Herpes virus
what is the presentation of anterior uveitis?
it usually presents with unilateral symptoms that start spontaneously without a history of trauma or precipitating events. They may occur with a flare of an associated disease such as reactive arthritis.
Symptoms Include:
- dull aching painful red eye
- ciliary flush - a ring of red spreading from the cornea outwards
- reduced visual acuity
- floaters and flashes
- sphincter muscle contraction causing miosis (contracted pupil)
- photohobiadue to ciliary muscle spasm
- pain on movement
- abnormally shaped pupil due to posterior synechiae (adhesions) pulling the iris into abnormal shapes
how should anterior uveitis be managed?
urgent review by ophthalmology - same day assessment - they need fully slit lamp assessment of the different structures of the eye and intraocular pressure to establish the diagnosis
Slit lamp exam
hypopyon - inflammatory cells and pus collecting
kerartic precipitates
ciliary flush
treatment choices
- steroids
- cycloplegic-mydriatic medications such as atropine - Cycloplegic means paralysing the ciliary muscles. Mydriatic means dilating the pupils. Cyclopentolate and atropine are antimuscarinic medications that blocks to the action of the iris sphincter muscles and ciliary body. These dilate the pupil and reduce pain associated with ciliary spasm by stopping the action of the ciliary body.
- immunosupressants such as DMARD and TNF inhibitors
- laser therapy, cryotherapy or surgery may be needed in severe cases
what is blepharitis?
Blepharitis is inflammation of the eyelid margins.
common in patients with rosacea
what can cause blepharitis?
meibomian gland dysfunction (common, posterior blepharitis)
seborrhoeic dermatitis/staph infection (anterior blepharitis)
how does blepharitis present?
burning sensation itching sensation grittiness and discomfort particularly around the eyelid margins foreign body sensations crusting of eyelids dry eyes
how do you manage blepharitis?
soften the lid margin using hot compresses twice a day
lid hygiene
Lubricating eye drops can be used to relieve symptoms:
Hypromellose is the least viscous. The effect lasts around10 minutes.
Polyvinyl alcohol is the middle viscous choice. It is worth starting with these.
Carbomer is the most viscous and lasts 30 – 60 minutes.
what is a stye?
Stye, also known as hordeolum, is an acute infectious process involving abscess formation at the upper or lower eyelid. One of 3 glands is typically infected: the meibomian glands or the glands of Zeis and Moll (ciliary glands).
Hordeolum externum is an infection of the glands of Zeis or glands of Moll. The glands of Moll are sweat glands at the base of the eyelashes. The glands of Zeis are sebaceous glands at the base of the eyelashes. A stye causes a tender red lump along the eyelid that may contain pus.
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.
what is chalazion?
acuteA chalazion occurs when a Meibomian gland becomes blocked and swells up. It is often called a Meibomian cyst. It presents with a swelling in the eyelid that is typically not tender. It can be tender and red.
how do you manage a stye?>
topical Abx - bacitracin ophthalmic or erythromycin ophthalmic
warm compresses plus massage
how is chalazion managed?
warm compress plus massage plus lid hygiene
what is entropion?
Entropion is where the eyelid turns inwards with the lashes against the eyeball. This results in pain and can result in corneal damage and ulceration.
Initial management is by taping the eyelid down to prevent it turning inwards. Definitive management is with surgical intervention. When the eyelid is taped down it is essential to prevent the eye drying out by using regular lubricating eye drops.
A same day referral to ophthalmology is required if there is a risk to sight.
what is ectropion ?
Ectropion is where the eyelid turns outwards with the inner aspect of the eyelid exposed. It usually affects the bottom lid. This can result in exposure keratopathy as the eyeball is exposed and not adequately lubricated and protected.
Mild cases may not require treatment. Regular lubricating eye drops are used to protect the surface of the eye. More significant cases may require surgery to correct the defect.
A same day referral to ophthalmology is required if there is a risk to sight.
