Flashes, floaters and transient visual disturbance
Itchy or irritating eyes or eyelids
This is a common reason for an urgent surgery appointment. If a visit request is made, try to negotiate consultation in surgery, where optimal examination conditions and equipment are to hand. Carefully examine to assess acuity, state of the cornea and pupillary reflexes.
COMMON
acute conjunctivitis (allergic or infective)
acute iritis
acute glaucoma
keratitis/corneal ulcer
corneal abrasion or superficial foreign body (FB)
OCCASIONAL
episcleritis/scleritis
keratoconjunctivitis sicca
trauma: contusion and penetrating wound, burns (arc eye and chemical)
orbital cellulitis
RARE
carotico-cavernous fistula (rupture of carotid aneurysm)
gout (urate deposits in conjunctiva or sclera)
granulomatous disorders: TB, sarcoid, toxoplasmosis
onchocerciasis (transmitted by Simulium black fly in Africa)
tumour: primary eye tumour, invasion from nasopharyngeal tumour
In practice, the problem is either easily treated by the GP (e.g. conjunctivitis or foreign body) or usually requires urgent referral. The GP’s role in investigating the painful red eye is therefore very limited.
Swab of discharge for microbiology: very occasionally helpful in conjunctivitis not settling with usual treatment.
Blood: raised WCC and ESR/CRP may support diagnosis of inflammatory disorders. Rheumatoid factor in suspected rheumatoid arthritis (RA); HLA-B27 usually positive in ankylosing spondylitis. The latter investigations would normally be performed at leisure rather than in the acute situation, when an underlying collagen disease is suspected (e.g. iritis).
Intraocular pressure measurement is essential if acute glaucoma is suspected. Usually done by a specialist.
If in serious doubt about the diagnosis, refer for urgent assessment – this is one scenario where a delay in treatment can have devastating consequences.
Don’t rely on the patient’s subjective assessment of blurring of vision – check the visual acuity.
Remember to evert the upper lid to check for a concealed foreign body.
Review the patient 24–48 hours after removing a foreign body to ensure that the cornea has healed.
Never use mydriatics when examining the red eye: you may precipitate acute glaucoma.
Bilateral red eye is usually caused by conjunctivitis. If unilateral, consider other causes.
Failure to recognise herpetic corneal ulcer or acute glaucoma may lead to permanent visual loss. If in doubt, refer for urgent specialist opinion.
Never instil steroid drops unless you are absolutely sure you are managing the problem correctly and have excluded herpetic ulceration.
Take a careful history when dealing with foreign bodies. Any possibility of a high-speed impact (e.g. grinding metal) requires urgent specialist assessment to exclude intraocular foreign body.
Diplopia is nearly always binocular, with movement of one eye being limited for a number of possible reasons. Although relatively uncommon as a presenting symptom, the majority of causes are significant and therefore careful assessment is essential.
COMMON
physiological (focusing too near, or perceiving objects nearer than those focused on)
intoxication: prescribed sedation, non-prescribed drugs, especially excess alcohol, opiates, benzodiazepines
stroke
mild head injury, causing temporary diplopia
facial bone trauma – orbital and zygomatic fracture
OCCASIONAL
mononeuropathy, e.g. diabetes, MS
orbital disease (usually associated with pain and proptosis) and after surgery (scarring limiting globe movement)
Guillain–Barré syndrome
palsy of third, fourth or sixth cranial nerves due to intracranial space-occupying lesion (haemorrhage, tumour, aneurysm, abscess, cavernous sinus thrombosis)
myasthenia gravis
monocular diplopia: early cataract, irregularity of corneal surface, e.g. post trauma or inflammation
RARE
ophthalmoplegic migraine
Tolosa–Hunt syndrome: granulomatous or inflammatory process in anterior portion of cavernous sinus or superior orbital fissure
pseudoparalysis of ocular muscles: dysthyroid disease; Duane’s syndrome (congenital fibrosis of lateral rectus)
orbital myositis
pituitary exophthalmos
LIKELY: none; FBC, ESR/CRP, lipid studies, urinalysis, fasting glucose or HbA1c.
POSSIBLE: TFT, X-rays, CT/MRI scan.
SMALL PRINT: edrophonium test, EMG, CSF studies, angiography.
No investigation is indicated in primary care for the most common causes – referral is the likeliest course of action.
FBC, ESR/CRP, lipid studies – if stroke suspected and admission not required. FBC and ESR/CRP will also provide evidence of inflammatory conditions.
Urinalysis for glucose/fasting glucose or HbA1c – to investigate possible diabetes.
TFT will reveal hyperthyroidism.
Other investigations (and possibly some of the above) are likely to be carried out in secondary care: skull and facial bone X-rays in trauma cases; CT or MRI scan (head injury, stroke, MS, space-occupying lesion); specialist neurological investigations (edrophonium test, single-fibre EMG studies, CSF examination, angiography).
Establish if the diplopia is binocular or not. Uniocular double vision has a much narrower differential diagnosis.
Take time to clarify the symptom. Sometimes, patients complain of ‘double vision’ when they really mean blurring – and vice versa.
The cover test is a reliable way to find out which eye is affected.
Fourth cranial nerve palsy produces diplopia on looking downwards and inwards, often noticed when descending stairs. The patient may try to compensate by tilting the head – so-called ocular torticollis.
Intoxication in conjunction with a head injury is commonly seen in custody medicine and A&E departments. Admission for neurological observation is strongly recommended.
Diplopia of acute onset may well reflect serious pathology – refer for urgent assessment.
Intermittent diplopia should not be dismissed too readily as insignificant – remember that myasthenia gravis and multiple sclerosis are possibilities.
Because of their close proximity to the eye, and their occasional cosmetic effect, eyelid problems can be disproportionately distressing to the patient. The differential diagnosis is wide – so the temptation to treat this presentation as a ‘quickie’ via a brief examination shouldn’t distract from the need to take a careful history.
COMMON
stye
blepharitis
meibomian cyst
xanthelasma
blocked tear duct
OCCASIONAL
periorbital oedema, e.g. orbital cellulitis, herpes zoster, angio-oedema, nephrotic syndrome, insect bite
ectropion
entropion (may be secondary trichiasis)
eczema (seborrhoeic, allergic)
ptosis (congenital, oculomotor nerve palsy, Horner’s syndrome, myasthenia gravis, senile, myotonic dystrophy)
muscular problems (myokymia, blepharospasm)
RARE
malignant growth, e.g. basal cell carcinoma
benign growths, e.g. papilloma, haemangioma
dacrocystitis
alopecia
molluscum contagiosum
lice
LIKELY: lipid profile.
POSSIBLE: urinalysis, FBC, LFT.
SMALL PRINT: tests for ptosis, biopsy.
Lipid profile: if xanthelasma, as may indicate hypercholesterolaemia.
Urinalysis: proteinuria in nephrotic syndrome.
FBC: WCC raised in infective process, e.g. cellulitis.
LFT: hypoproteinaemia in nephrotic syndrome.
Further tests for ptosis (usually in secondary care), e.g. CXR (Horner’s), edrophonium test (myasthenia), blood sugar and brain scan (oculomotor palsy).
Biopsy – if suspicion of malignancy.
A meibomian cyst is often misdiagnosed – by patient and doctor – as a stye, particularly if it is infected.
Entropion with secondary trichiasis may be overlooked as a cause of a recurring sore, watering eye, especially in the elderly.
Myokymia – recurrent focal twitching of the orbicularis oculi – is harmless but may distress or alarm the patient.
Many patients with xanthelasma will already have been ‘noted’ and so have had their cholesterol measured. Enquire about this before wasting resources on further unnecessary checks.
Orbital cellulitis requires urgent inpatient treatment.
Bilateral ptosis which deteriorates through the day may indicate myasthenia gravis.
New onset of unilateral ptosis requires investigation – possible diagnoses range from diabetes to malignancy.
Loss of the eyelashes is a poor prognostic sign in alopecia.
Unilateral eyelash loss, with or without apparent blepharitis, may be a sign of an eyelid tumour.
This symptom can be very difficult to fathom, not least because patients often find it nigh on impossible to describe exactly what they’ve experienced. Patience and a painstaking approach are essential – most of the clues are likely to be in the history rather than in the examination. This section does not cover double vision, gradual loss of vision or persistent sudden loss of vision, which are dealt with elsewhere.
COMMON
‘normal’ floaters
migraine
posterior vitreous detachment
amaurosis fugax
retinal detachment
OCCASIONAL
temporal arteritis
vasovagals and orthostatic hypotension (commonly cause the symptom but rarely present with it)
vitreous haemorrhage
medication (e.g. transient blurred vision with anticholinergics, blue tinge to vision with sildenafil)
poorly controlled diabetes
TIA
optic neuritis
papilloedema
trauma
posterior uveitis
seizures
psychological
The GP is highly unlikely to initiate any investigations in this situation – apart, perhaps, from a blood sugar or HbA1c to check for undiagnosed diabetes or an urgent ESR in suspected temporal arteritis. Otherwise, any investigations required would be arranged by the ophthalmologist or neurologist after urgent or routine referral, depending on the clinical picture.
It is tempting to ‘bounce’ some of these cases to a local optician for assessment. Resist this approach – you may delay an important diagnosis and, besides, even a thorough examination is unlikely to provide anything like as much relevant information as a careful history.
Some patients find it easier to ‘draw’ their visual disturbance than describe it.
Floaters are a fairly common presentation – one of the key issues to establish is the duration of the symptom. The longer they have been present, the more you can be reassured that they are ‘normal’.
Remember that ocular migraine can occur without the ‘usual’ headache.
A sudden onset of a shower of floaters is significant – especially if accompanied by flashing lights or blurred vision. Refer urgently to exclude a retinal detachment.
Do not forget temporal arteritis as a cause of transient visual disturbance, especially in patients aged 50 or more. Treat with high-dose steroids on suspicion of this diagnosis – do not wait for the results of blood tests.
Remember to check whether a young woman with migrainous visual disturbance is on the combined contraceptive pill and advise accordingly.
Amaurosis fugax is a form of TIA and should be managed as such – apply your local ‘TIA pathway’.
The four major causes of gradual blindness in the world are: cataract, onchocerciasis, vitamin A deficiency and trachoma. The latter three are very rare in the UK. Cataract occurs in 75% of over-65s, but only 20% of 45- to 65-year-olds. Most cases of gradual loss of vision encountered in primary care arrive via the optician, often with a letter outlining the problem and suggesting referral to an ophthalmologist.
COMMON
cataract
chronic glaucoma
diabetic and hypertensive retinopathy
senile macular degeneration
gradual inferior retinal detachment
OCCASIONAL
choroidoretinitis
optic neuritis (in MS)
Paget’s disease of the skull
retinitis pigmentosa
intraorbital or intracranial tumours
RARE
syphilis
cerebromacular degeneration
toxic amblyopia (tobacco, methanol, arsenic, quinine, carbon bisulphide)
choroidal melanoma
Leber’s hereditary optic atrophy
The only investigation the GP is likely to perform is a urinalysis and/or blood sugar or HbA1c for suspected diabetes. If glaucoma is a possibility, and the patient has not already seen the optician, then optician referral will provide information about fields and pressures. More obscure tests – such as posterior pole ultrasound and CT scan for retinal, or other, tumours; syphilis serology; skull X-ray for Paget’s disease; and neurological investigations for MS – are rarely required and are inevitably arranged in secondary care.
Opticians will tend to report cataracts in the elderly routinely. Referral for surgery is only required if the problem is significantly impairing the individual’s normal activities.
The presence of a cataract in relatively young patients is unusual and should prompt referral regardless of visual impairment – there may be a rare underlying metabolic cause.
Remember that significant glaucoma or other causes of visual loss may render the individual unfit to drive.
The elderly patient with a cataract whose vision is not improved considerably with the pinhole test probably has macular degeneration too, and so is unlikely to benefit much from cataract extraction.
It can be very difficult to establish in an elderly person whether the problem really has been gradual in onset or whether the history is more sudden; if in doubt, refer urgently as the cause may be acute and remediable.
Progressive early morning headache or proptosis with gradual loss of vision suggests a tumour. Refer urgently.
Gradual or recurrent visual loss or blurring with other intermittent neurological symptoms, especially in younger patients, suggests the possibility of MS.
This is a nuisance symptom which patients present with directly, or via their optician. It can be very difficult to ascertain whether the problem is arising from the eyelid or the eye itself. Often, the symptoms affect both and the causes overlap – which is why they’re considered together here.
COMMON
allergic conjunctivitis (usually hay fever)
infective conjunctivitis
dry eyes
blepharitis
blocked tear duct
OCCASIONAL
ectropion
entropion
eczema of the eyelids
effect of contact lenses or solutions
iatrogenic (oral or local medication)
foreign body (though usually presents with pain and redness)
RARE
pubic lice (can affect eyelashes)
floppy eyelid syndrome (chronic conjunctivitis with lax eyelids in obese, middle-aged men)
sebaceous gland carcinoma
thyroid eye disease
LIKELY: none.
POSSIBLE: swab, Schirmer’s test.
SMALL PRINT: TFT, thyroid autoantibodies, MRI orbits, biopsy.
Swab: may be necessary in persistent discharge; essential in neonates who’ve had sticky eyes since birth.
Schirmer’s test: to assess for dry eye – may be performed by the optician.
TFT, thyroid autoantibodies, MRI orbits – may be required in suspected thyroid eye disease.
Biopsy: rarely, if sebaceous gland carcinoma suspected.
Diagnosis can be difficult and an optician’s input may be invaluable.
Enquire about the use of OTC drops and their effect – this may give clues to the underlying problem. Sometimes, the drops themselves may be the cause.
It can be easy to overlook entropion – ask the patient to squeeze the eyes shut, then suddenly open them, in which case a subtle entropion should be revealed.
Bear in mind that patients with dry eyes sometimes paradoxically complain of a stringy discharge.
Remember that thyroid eye disease can present before biochemical dysfunction – if in doubt, refer.
Do not overlook a foreign body as a possible cause, especially if the history is vague and the symptoms unilateral.
Chlamydia and gonorrhoea must be excluded in the neonate with a sticky eye or eyes from birth.
The rare sebaceous gland carcinoma causes blepharitis-type symptoms, but with localised inflammation and localised loss of lashes.
Sudden loss of vision is a genuine GP emergency. Most causes require an urgent ophthalmological opinion as there is little that the GP can do. This particular symptom is not often encountered in general practice – a prompt appointment or visit and a careful examination are necessary to assess the situation and exclude the causes not requiring urgent specialist treatment.
COMMON
acute glaucoma
vitreous haemorrhage
central retinal artery occlusion
migraine
CVA or TIA
OCCASIONAL
central retinal vein occlusion
retrobulbar (optic) neuritis
retinal detachment
temporal arteritis
posterior uveitis
RARE
hysteria
cortical blindness (non-vascular)
optic nerve injury
quinine poisoning
In practice, there are none worth doing at the time, as the vast majority of cases will be referred urgently. Virtually all tests will therefore be arranged by the specialist, usually after the event, to look for underlying causes. Such investigations include the following.
Screening for diabetes: undetected retinopathy may have preceded vitreous haemorrhage.
FBC: PCV may be raised in central retinal vein occlusion.
ESR: raised in temporal arteritis.
Multiple microbiological investigations are needed for posterior uveitis.
Posterior pole ultrasound may be useful in vitreous haemorrhage to identify treatable causes.
CT scan only useful to investigate cerebral causes (CVA or cortical blindness).
Acute visual disturbance is often difficult to diagnose accurately and very alarming for the patient. If in doubt, refer urgently, or, at the very least, review in a few hours.
The patient’s assessment of visual loss, and its severity, is highly subjective – if at all possible, test it with a Snellen chart.
Always keep spare batteries handy for your ophthalmoscope!
Don’t forget that the visual disturbance may be the presenting symptom of some other pathology, such as hypertension, temporal arteritis or diabetes.
Don’t miss a heart murmur or carotid bruit. These may be present in retinal artery occlusion and TIA/CVA.
A cherry red spot on the fovea is pathognomic of retinal artery occlusion.
Never use mydriatics to aid examination at the bedside: these will cloud the clinical picture and may even precipitate acute glaucoma.