Ophthalmology Flashcards
Conditions and presentations
What is glaucoma
Glaucoma is a group of disorders characterised by optic neuropathy due, in the majority of patients, to raised intraocular pressure (IOP).
Not all patients with raised I have glaucoma and vice versa
Factors which predispose to AACG (Acutely angle-closure glaucoma)
hypermetropia (long-sightedness)
pupillary dilatation
lens growth associated with age
Features of AACG
- severe pain: may be ocular or headache
- decreased visual acuity
- symptoms worse with mydriasis (e.g. watching TV in a dark room)
- hard, red-eye
- haloes around lights
- semi-dilated non-reacting pupil
- corneal oedema results in dull or hazy cornea
- systemic upset may be seen, such as nausea and vomiting and even abdominal pain
Investigations of AACG
tonometry to assess for elevated IOP
gonioscopy (literally looking, oscopy, at the angle, gonio): a special lens for the slit lamp that allows visualisation of the angle
Management of AACG
- typically an emergency and should prompt urgent referral to ophthalmology
Emergency medical treatment is required to lower the IOP with more definitive surgical treatment given once the acute attack has settled.
Example regime of managing AACG
combination of eye drops, for example:
a direct parasympathomimetic (e.g. pilocarpine, causes contraction of the ciliary muscle → opening the trabecular meshwork → increased outflow of the aqueous humour)
a beta-blocker (e.g. timolol, decreases aqueous humour production)
an alpha-2 agonist (e.g. apraclonidine, dual mechanism, decreasing aqueous humour production and increasing uveoscleral outflow)
intravenous acetazolamide
reduces aqueous secretions
some guidelines also recommend the use of topical steroids to reduce inflammation
Definitive management of AACG
laser peripheral iridotomy
creates a tiny hole in the peripheral iris → aqueous humour flowing to the angle
Age-related macular degeneration
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 of ARMD
- advancing age (greatest risk)
- smoking
- current smokers are twice as likely as non-smokers
- family history
- ischaemic cardiovascular disease
- hypertension
- dyslipidaemia
- diabetes mellitus.
Investigation of ARMD
- slit-lamp microscopy (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,
optical 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.
Signs of ARMD during investigation
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.
Clinic features of ARMD
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
Treatment of ARMD
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
Risk of laser photocoagulation
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.
Allergic conjunctivitis 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)
Management of allergic conjunctivitis
first-line: topical or systemic antihistamines
second-line: topical mast-cell stabilisers, e.g. Sodium cromoglicate and nedocromil
Anterior uveitis
important differentials of a red eye
also referred to as iritis.
inflammation of the anterior portion of the uvea - iris and ciliary body.
What genes is associated with anterior uveitis
HLA-B27
Features of anterior uveitis
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; describes pus and inflammatory cells in the anterior chamber, often resulting in a visible fluid level
visual acuity initially normal → impaired
Associated conditions with anterior uveitis
ankylosing spondylitis
reactive arthritis
ulcerative colitis, Crohn’s disease
Behcet’s disease
sarcoidosis: bilateral disease may be seen
Management of anterior uveitis
urgent review by ophthalmology
cycloplegics (dilates the pupil which helps to relieve pain and photophobia) e.g. Atropine, cyclopentolate
steroid eye drops
Argyll-Robertson pupil
Argyll-Robertson pupil is one of the classic pupillary syndrome. It is sometimes seen in neurosyphilis.
What conditions are associated with HLA-B27
- Ankylosing spondylitis
- Reactive arthritis (Reiter’s syndrome)
-psoriatic arthritis
-enteropathic arthritis (associated with IBD)
Juvenile idiopathic arthritis
Acute anterior uveitis
Axial spondyloarthritis
Behçet’s disease (in some populations)
Reactive arthritis following certain infections, such as Chlamydia trachomatis or Salmonella spp.
Argyll-Robertson pupil ARP—>PRA
Accommodation Reflex Present (ARP) but Pupillary Reflex Absent (PRA)
Features of Argyll-Robertson pupil
small, irregular pupils
no response to light but there is a response to accommodate
Causes of Argyll-Robertson pupil
diabetes mellitus
syphilis
Blepharitis
Blepharitis is inflammation of the eyelid margins. It may due to either meibomian gland dysfunction (common, posterior blepharitis) or seborrhoeic dermatitis/staphylococcal infection (less common, anterior blepharitis).
What condition is most associated with blepharitis
Rosacea
Function of the meibomian gland
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 turns leads to irritation
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
Management of blepharitis
softening of the lid margin using hot compresses twice a day
‘lid hygiene’ - mechanical removal of the debris from lid margins
cotton wool buds dipped in a mixture of cooled boiled water and baby shampoo is often used
an alternative is sodium bicarbonate, a teaspoonful in a cup of cooled water that has recently been boiled
artificial tears may be given for symptom relief in people with dry eyes or an abnormal tear film
Blurred vision
Loss of clarity or sharpness of vision
Patients who have it will have long-term refractive errors
Make sure to assess for other symptoms such as visual loss, double vision and floaters
Causes of blurred vision (7)
refractive error: most common
cataracts
retinal detachment
age-related macular degeneration
acute angle closure glaucoma
optic neuritis
amaurosis fugax
Assessment of blurred vision
visual acuity with a Snellen chart
pinhole occluders are a useful way to check for whether the blurred vision is due to a refractive error or not
if the blurring improves with a pinhole occluder then likely cause is a refractive error
visual fields
fundoscopy
Management of blurred vision
depends on the suspected underlying cause
if gradual onset, corrected by pinhole occluder and no other associated symptoms then an optician review would be the next step
other patients should be seen by ophthalmology. If there are associated symptoms such as visual loss or pain this should be urgent
Thyroid eye disease
Grave’s disease
Pathophysiology of grave’s disease
it is thought to be caused by an autoimmune response against an autoantigen, possibly the TSH receptor → retro-orbital inflammation
the inflammation results in glycosaminoglycan and collagen deposition in the muscles
Prevention of grave’s eye disease
- smoking
- radioiodine treatment
Features of grave’s eye disease
- eu/ hypo/ hyperthyroid at time of presentation
- exophthalmos
conjunctival oedema
optic disc swelling
ophthalmoplegia
inability to close the eyelids
Dry eye
Managment of grave’s eye disease
smoking cessation
topical lubricants may be needed to help prevent corneal inflammation caused by exposure
steroids
radiotherapy
surgery
Complications of grave’s eye disease
- exposure kerathopathy
- optic neuropathy
-strabismus and dipolopia
Exposure kerathopathy
- eye lid retraction and proptosis causes cornea to become excessively exposed
Causes dryness and imitation and corneal ulceration
Pt may report a foreign body experience
Photophobia
Can cause scarring and vision impairment as well
Optic neuropathy
enlarged extraocular muscles compress the optic nerve at the apex of the orbit → a reduction in visual acuity, colour vision deficits, and visual field defect
it requires urgent medical intervention to prevent permanent vision loss.
