Opthal Flashcards
Cataracts
What is it?
Who gets it?
Causes?
Presentation?
Ix?
Classification?
Mx?
complications post-surgery?
Cataracts are the leading cause of curable blindness worldwide
A cataract is a common eye condition where the lens of the eye gradually opacifies i.e. becomes cloudy. This cloudiness makes it more difficult for light to reach the back of the eye (retina), thus causing reduced/blurred vision.
Epidemiology
- F>M
- increases with age
- 1/3 >65yo’s have a visually-impairing cataract in either one or both eyes!??
Causes
Most common cause = Normal ageing process
Other possible causes
- Smoking
- Increased alcohol consumption
- Trauma
- Diabetes mellitus
- Long-term corticosteroids
- Radiation exposure
- Myotonic dystrophy
- Hypocalcaemia
Patients typically present with a gradual onset of:
- Reduced vision
- Faded colour vision: making it more difficult to distinguish different colours
- Glare: lights appear brighter than usual
- Halos around lights
Signs = A Defect in the red reflex*
Ix: opthalmoscopy + slit lamp
Ophthalmoscopy: done after pupil dilation. Findings: normal fundus and optic nerve
Slit-lamp examination. Findings: visible cataract
Classification
Nuclear = change in the lens’ refractive index, common in old age
Polar: localized, commonly inherited, lie in the visual axis
Subcapsular: due to steroid use, just deep to the lens capsule, in the visual axis
Dot opacities: common in normal lenses, also seen in diabetes and myotonic dystrophy
Mx: brighter lighting/stronger glasses or surgery (definitive)
Non-surgical: In the early stages, age-related cataracts can be managed conservatively by prescribing stronger glasses/contact lens, or by encouraging the use of brighter lighting. These options help optimise vision but do not actually slow down the progression of cataracts, therefore surgery will eventually be needed.
Surgery: Surgery is the only effective treatment for cataracts. This involves removing the cloudy lens and replacing this with an artificial one.
Referral for surgery depends on; whether visual impairment is present, impact on quality of life, and patient choice. Also whether both eyes are affected and the possible risks and benefits of surgery should be taken into account. Prior to cataract surgery, patients should be provided with information on the refractive implications of various types of intraocular lenses. After cataract surgery, patients should be advised on the use of eye drops and eyewear, what to do if vision changes and the management of other ocular problems. Cataract surgery has a high success rate with 85-90% of patients achieving 6/12 corrected vision (on a Snellen chart) postoperatively.
Complications following surgery:
- Posterior capsule opacification: thickening of the lens capsule
- Retinal detachment
- Posterior capsule rupture
- Endophthalmitis: inflammation of aqueous and/or vitreous humour
*the red reflex is essentially the reddish-orange reflection seen through an ophthalmoscope when a light is shone on the retina. Cataracts will prevent light from getting to the retina, hence you see a defect in the red reflex.
Central retinal arterial occlusion
What is it?
3 Features?
It is due to thromboembolism (from atherosclerosis) or arteritis (e.g. temporal arteritis)
Features
1. sudden, painless unilateral visual loss
2. relative afferent pupillary defect
3. ‘cherry red’ spot on a pale retina
Mx = difficult and the prognosis is poor
any underlying conditions should be identified and treated (e.g. intravenous steroids for temporal arteritis)
if a patient presents acutely then Intraarterial thrombolysis may be attempted but currently, trials show mixed results.
Central retinal vein occlusion (CRVO)
RF’s?
Features?
Key differential?
Mx?
CRVO is a differential for sudden painless loss of vision
Risk factors
increasing age
hypertension
cardiovascular disease
glaucoma
polycythaemia
Features
- sudden, painless reduction or loss of visual acuity, usually unilaterally
+ - fundoscopy shows widespread hyperaemia and severe retinal haemorrhages - ‘stormy sunset’
A key differential is branch retinal vein occlusion (BRVO) - this occurs when a vein in the distal retinal venous system is occluded and is thought to occur due to blockage of retinal veins at arteriovenous crossings. It results in a more limited area of the fundus being affected.
Mx = the majority of patients are managed conservatively
indications for treatment in patients with CRVO include:
- Macular oedema = intravitreal anti-vascular endothelial growth factor (VEGF) agents
- Retinal neovascularization = laser photocoagulation
Allergic Conjunctivitis
Features and mx?
Allergic conjunctivitis may occur alone but is often seen in the context of hay fever
Features
Bilateral symptoms conjunctival erythema, conjunctival swelling (chemosis)
Itch is prominent
the eyelids may also be swollen
May be a history of atopy
May be seasonal (due to pollen) or perennial (due to dust mite, washing powder or other allergens)
Mx:
1st = Topical or systemic antihistamines
2nd = topical mast-cell stabilisers, e.g. Sodium cromoglicate and nedocromil
Glaucoma
Ix: Tonometry + gonioscopy should be performed in patients with suspected acute angle-closure glaucoma
Keratitis
What is it?
Causes?
Mx?
Keratitis = inflammation of the cornea. Microbial keratitis is not like conjunctivitis - it is potentially sight threatening!! and should therefore be urgently evaluated and treated.
Causes
bacterial = Staphylococcus aureus. Pseudomonas aeruginosa is seen in contact lens wearers
fungal
amoebic (5%) = increased incidence if eye exposure to soil or contaminated water. Pain is classically out of proportion to the findings
parasitic: onchocercal keratitis (‘river blindness’)
Remember, other factors may causes keratitis:
viral: herpes simplex keratitis
environmental
photokeratitis: e.g. welder’s arc eye
exposure keratitis
contact lens acute red eye (CLARE)
Clinical features
Features
- red eye: pain and erythema
- photophobia
- foreign body, gritty sensation
- hypopyon may be seen (accumulation of white cells under the eye)
Evaluation and management
contact lens wearers who present with a red+painful eye = Refer to eye specialist for diagnosis with a slit lamp to rule out microbial keratitis
Mx:
stop using contact lens until the symptoms have fully resolved
topical antibiotics (Quinolones)
cycloplegic for pain relief
e.g. cyclopentolate
Complications may include:
corneal scarring
perforation
endophthalmitis
visual loss
Macular degeneration
UNSURE WHAT I ACTUALLY NEED TO KNOW
What is it?
Who gets it?
RF’s?
Classification?
Age-related macular degeneration (ARMD) is the most common cause of blindness in the UK
Degeneration of the central retina (macula) is the key feature with changes usually bilateral.
ARMD is characterised by degeneration of retinal photoreceptors that results in the formation of drusen which can be seen on fundoscopy and retinal photography.
It is more common with advancing age and is more common in females.
Risk factors
advancing age itself is the greatest risk factor for ARMD
smoking
family history is also a strong risk factor for developing ARMD
any increased risk of ischaemic cardiovascular disease, such as hypertension, dyslipidaemia and diabetes mellitus.
Classification
Traditionally two forms of macular degeneration are seen:
dry macular degeneration
90% of cases
also known as atrophic
characterised by drusen - yellow round spots in Bruch’s membrane
wet macular degeneration
10% of cases
also known as exudative or neovascular macular degeneration
characterised by choroidal neovascularisation
leakage of serous fluid and blood can subsequently result in a rapid loss of vision
carries the worst prognosis
Clinical features
Patients typically present with a subacute onset of visual loss with:
- a reduction in visual acuity, particularly for near field objects
gradual in dry ARMD
subacute in wet ARMD - difficulties in dark adaptation with an overall deterioration in vision at night
- fluctuations in visual disturbance which may vary significantly from day to day
- they may also suffer from photopsia, (a perception of flickering or flashing lights), and glare around objects
- visual hallucinations may also occur resulting in Charles-Bonnet syndrome
Signs:
distortion of line perception may be noted on Amsler grid testing
fundoscopy reveals the presence of drusen, yellow areas of pigment deposition in the macular area, which may become confluent in late disease to form a macular scar.
in wet ARMD well demarcated red patches may be seen which represent intra-retinal or sub-retinal fluid leakage or haemorrhage.
Ix = slit-lamp microscopy & colour fundus photography
to identify any pigmentary, exudative or haemorrhagic changes affecting the retina which may identify the presence of ARMD. This is usually accompanied by colour fundus photography to provide a baseline against which changes can be identified over time.
fluorescein angiography is utilised if neovascular ARMD is suspected, as this can guide intervention with anti-VEGF therapy. This may be complemented with indocyanine green angiography to visualise any changes in the choroidal circulation.
ocular coherence tomography is used to visualise the retina in three dimensions because it can reveal areas of disease which aren’t visible using microscopy alone.
Mx:
the AREDS trial examined the treatment of dry ARMD in 3640 subjects. It showed that a combination of zinc with anti-oxidant vitamins A,C and E reduced progression of the disease by around one third. Patients with more extensive drusen seemed to benefit most from the intervention. Treatment is therefore recommended in patients with at least moderate category dry ARMD.
vascular endothelial growth factor (VEGF)
VEGR is a potent mitogen and drives increased vascular permeability in patients with wet ARMD
a number of trials have shown that use of anti-VEGF agents can limit progression of wet ARMD and stabilise or reverse visual loss
evidence suggests that they should be instituted within the first two months of diagnosis of wet ARMD if possible
examples of anti-VEGF agents include ranibizumab, bevacizumab and pegaptanib,. The agents are usually administered by 4 weekly injection.
laser photocoagulation does slow progression of ARMD where there is new vessel formation, although there is a risk of acute visual loss after treatment, which may be increased in patients with sub-foveal ARMD. For this reason anti-VEGF therapies are usually preferred.
Orbital cellulitis
What is it?
Whats preorbital/septal cellulitis?
Risk factors?
Presentation?
Differentiating from preseptal cellulitis?
Orbital cellulitis is the result of an infection affecting the fat and muscles posterior to the orbital septum, within the orbit but not involving the globe.
It is usually caused by URTI spreading from the sinuses and carries a high mortality rate
Orbital cellulitis is a medical emergency requiring hospital admission and urgent senior review!!
Periorbital (preseptal) cellulitis is a less serious superficial infection anterior to the orbital septum, resulting from a superficial tissue injury (chalazion, insect bite etc…). but, Periorbital cellulitis can progress to orbital cellulitis!
Risk factors;
- pt is 7-12yo
- Previous sinus infection
- Lack of Haemophilus influenzae type b (Hib) vaccination
- Recent eyelid infection/ insect bite on eyelid (periorbital cellulitis)
- Ear or facial infection
Presentation
- Redness and swelling around the eye
- Severe ocular pain
- Visual disturbance
- Proptosis
- Ophthalmoplegia/pain with eye movements
- Eyelid oedema and ptosis
- Drowsiness +/ Nausea/vomiting in meningeal involvement (Rare)
Differentiating orbital from preseptal cellulitis;
- Reduced visual acuity,
- Proptosis, -
- Ophthalmoplegia/pain with eye movements are NOT consistent with preseptal cellulitis
Ix: FBC + clinical exam + CT + blood culture
Full blood count – WBC elevated, raised inflammatory markers.
Clinical examination involving complete ophthalmological assessment – Decreased vision, afferent pupillary defect, proptosis, dysmotility, oedema, erythema
CT with contrast – Inflammation of the orbital tissues deep to the septum, sinusitis
Blood culture and microbiological swab to determine the organism. Most common bacterial causes – Streptococcus, Staphylococcus aureus, Haemophilus influenzae B.
Mx = admission to hospital for IV antibiotics
Retinal detachment
What is it?
5 RF’s
5 Features?
Mx?
Retinal detachment occurs when the neurosensory tissue that lines the back of the eye comes away from its underlying pigment epithelium.
It is a reversible cause of visual loss, provided it is recognised and treated before the macula is affected. If left untreated and symptomatic, retinal detachment will inevitably lead to permanent visual loss!
Risk factors
- diabetes mellitus
occurs as a result of breaks in the retina due to traction by the vitreous humour
these tears may proceed to detachment if left untreated - Myopia (short sightedness)
- Age
- Previous surgery for cataracts (accelerates posterior vitreous detachment)
- Eye trauma e.g. boxing
Features
- new onset floaters or flashes, as these indicate pigment cells entering the vitreous space or traction on the retina respectively
- sudden onset, painless and progressive visual field loss, described as a curtain or shadow progressing to the centre of the visual field from the periphery should also raise suspicion of detachment
if the macula is involved, central visual acuity and visual outcomes become much worse
- peripheral visual fields may be reduced, and central acuity may be reduced to hand movements if the macula is detached
- the swinging light test may highlight a relative afferent pupillary defect if the optic nerve is involved
- Fundoscopy - the red reflex is lost and retinal folds may appear as pale, opaque or wrinkled forms. If the break is small, however, it may appear normal.
Mx:
any patients with new onset flashes and floaters should be referred urgently (<24 hours) to an ophthalmologist for assessment with a slit lamp and indirect ophthalmoscopy for pigment cells and vitreous haemorrhage
Strabismus
what is it?
Ix and mx?
It is important to detect as uncorrected may lead to amblyopia (the brain fails to fully process inputs from one eye and over time favours the other eye).
Squint (strabismus) is characterised by misalignment of the visual axes. Squints may be divided into concomitant (common) and paralytic (rare).
Concomitant = Due to imbalance in extraocular muscles. Convergent is more common than divergent
Paralytic = Due to paralysis of extraocular muscles
Ix = Corneal light reflection + cover test
Corneal light reflection test - holding a light source 30cm from the child’s face to see if the light reflects symmetrically on the pupils
The cover test is used to identify the nature of the squint:
ask the child to focus on an object
cover one eye
observe movement of uncovered eye
cover other eye and repeat test
Mx = Referral to secondary care!
eye patches may help prevent amblyopia
Uveitis
What is it?
Associated conditions?
Features?
Mx?
Anterior uveitis describes inflammation of the anterior portion of the uvea - iris and ciliary body. It is associated with HLA-B27
Features
- acute onset
- ocular discomfort & pain (may increase with use)
- pupil may be small +/- irregular due to sphincter muscle contraction
- photophobia (often intense)
- blurred vision
- red eye
- lacrimation
- ciliary flush: a ring of red spreading outwards
- hypopyon (pus and inflammatory cells in the anterior chamber, often resulting in a visible fluid level)
- visual acuity initially normal → impaired
Associated conditions
ankylosing spondylitis
reactive arthritis
ulcerative colitis, Crohn’s disease
Behcet’s disease
sarcoidosis: bilateral disease may be seen
Mx: urgent specialist review + cycloplegics + steroid eye drops
Cycopeglics dilate the pupil which helps to relieve pain and photophobia e.g. Atropine, cyclopentolate
Vitreous haemorrhage
What is it?
3 Common causes?
3 Signs?
5 Ix?
It is one of the most common causes of sudden painless loss of vision.
Vitreous haemorrhage = bleeding into the vitreous humour. It causes disruption to vision to a variable degree, ranging from floaters to complete visual loss. The source of bleeding can be from disruption of any vessel in the retina as well as the extension through the retina from other areas.
Common causes (collectively account for 90% of cases):
- proliferative diabetic retinopathy (over 50%)
- posterior vitreous detachment
- ocular trauma: the most common cause in children and young adults
Patients typically present with an acute or subacute onset of:
- Painless visual loss or haze (commonest)
- red hue in the vision
- floaters or shadows/dark spots in the vision
Signs:
decreased visual acuity/field defect: variable depending on the location, size and degree of vitreous haemorrhage
Ix: fundoscopy + slit-lamp + USS + florescein angiography + CT
- Dilated fundoscopy: may show haemorrhage in the vitreous cavity
- Slit-lamp examination: red blood cells in the anterior vitreous
- Ultrasound: useful to rule out retinal tear/detachment and if haemorrhage obscures the retina
- Fluorescein angiography: to identify neovascularization
- Orbital CT: used if open globe injury
Once the bleeding stops, the blood is typically cleared from the retina at an approximate rate of 1% per day.
Infective Conjunctivitis
Features - bacterial vs viral?
Conjunctivitis is the most common eye problem presenting to primary care
It is characterised by sore, red eyes associated with a sticky discharge
Bacterial conjunctivitis:
Purulent discharge
Eyes may be ‘stuck together’ in the morning)
Viral conjunctivitis:
Serous discharge
Recent URTI
Preauricular lymph nodes
Mx = normally a self-limiting condition that usually settles without treatment within 1-2 weeks
advice should be given not to share towels
school exclusion is NOT necessary
topical antibiotic therapy is commonly offered to patients, e.g. Chloramphenicol.
Chloramphenicol drops are given 2-3 hourly initially whereas chloramphenicol ointment is given qds initially
Pregnant = topical fusidic acid twice daily instead
contact lens users;
topical fluoresceins should be used to identify any corneal staining
contact lens should NOT BE WORN during an episode of conjunctivitis
Red eye - how don you tell the difference between glaucoma or uveitis?
glaucoma: severe pain, haloes, ‘semi-dilated’ pupil
uveitis: small, fixed oval pupil, ciliary flush
Posterior uveitis = vision loss + sx of flashing lights or floater
What is Ardie tonic piupil and what are the signs?
Adie’s tonic pupil is a cause of ciliary ganglion dysfunction.
This would cause a dilated pupil and the anisocoria would be greater in bright light
Problems with the parasympathetic innervation of the eye can involve the parasympathetic nervous system entirely, the oculomotor nerve, the ciliary ganglion, or the iris itself.
