11 Ophthalmology

Always take a full ophthalmic history. Which eye is affected (are both)? What is the disturbance? Are there flashing lights or floaters? How quickly did the symptoms come on? How does it affect the patient's lifestyle (job, reading, watching TV)? Ask about prior ophthalmic/optician treatment and take a full medical and drug history. Family history of glaucoma may also be relevant.

of patients presenting with eye problems. Patients with potentially serious pathology include those with:

Have a low threshold for involving an ophthalmologist if a patient who is already blind in one eye, presents with a problem with the ‘good eye’.

is the key to eye examination: measure this first.

Use a Snellen chart, read at 6m, for each eye separately. Allow patients to use glasses if available, if not employ a pinhole (made using a needle through a piece of card). Use of a pinhole eliminates refractive error.

VA is expressed as:

For example, a patient whose VA is recorded as Right eye 6/5; Left eye 6/60 can read the bottom line with the right eye, but only the top line with the left eye. If patients read additional letters of the line below, record using + number of extra letters (eg 6/12 + 2).

Bring patients unable to read chart at 6m forward until they can read the chart (eg 3/60 = top line read at 3m). Very poor vision: try counting fingers or detecting hand movement at 1m, or light perception.

A hand-held chart at 30cm is an alternative if a full Snellen chart is unavailable—ability to read small print implies normal VA for that eye. For patients who are illiterate, there is an alternative chart with various different versions of the letter ‘E’—ask the patient to state which directions the 3 limbs of the letter point.

Record pupil size, shape, direct, and consensual responses to light and accommodation.

Check full range and ask about diplopia. Look for nystagmus.

Check carefully in patients with visual loss.

In a darkened room, first note the presence of a red reflex. A lost or ↓red reflex is an abnormal finding, typically caused by vitreous haemorrhage, cataracts, or major corneal abrasions. Assess the optic discs, look for retinal haemorrhages and vessel abnormalities.

Under a bright light look for inflammation or FBs.

If there is a possibility of FB, evert the upper eyelid by pressing down lightly over the upper lid with a cotton bud or orange stick and rotating the lid upwards over it. Ask the patient to look down throughout.

Learn how to use a slit lamp. It allows a detailed view of conjunctiva, cornea, and anterior chamber. Fluorescein staining reveals corneal abnormalities, particularly when viewed under blue light, when abrasions appear green. Fluorescein is available either in drop form or dried onto a strip. Remember that fluorescein can permanently stain clothes and contact lenses.

Digital assessment is unreliable. Formal measurement of intra-ocular pressure is useful, but requires training and is left to the eye specialist in many departments.

Palpate for tenderness if temporal arteritis is a possibility.

Sometimes, blepharospasm prevents satisfactory examination. Consider LA drops (1 or 2 drops of 1% amethocaine/tetracaine or 0.4% oxybuprocaine. 0.5% proxymetacaine causes less stinging and is useful in children).

Apply to the lower fornix (between lower eyelid and sclera) then ask the patient to keep the eye shut for 1–2min. Ointment has the advantage over drops in that it lasts longer: for example, chloramphenicol ointment needs to be given 4 times a day, whereas drops need to be given every 2hr initially. Theoretical concerns about aplastic anaemia are not well-founded (see the BNF).

Previously recommended following the administration of LA drops and for patients with corneal abrasions, they tend not to be useful unless the pad seals the eyelid shut.

Advise patients not to drive until their vision has returned to normal (this particularly applies after use of mydriatic agents). In addition, advise patients not to drive whilst wearing an eye pad. Document the advice given in the notes.

Blunt injury to the face may result in injury to the orbit or its bony margins. Compression of the eye in an antero-posterior direction (eg squash ball or fist) can cause a ‘blow-out’ fracture of the floor of the orbit.

Orbital compartment syndrome and blindness can arise from a retrobulbar haematoma. Unless diagnosed and treated as an emergency, optic nerve ischaemia develops and the patient can lose sight in the affected eye within a few hours. Proptosis, reduced eye movements, reduced visual acuity and pain all point to a retrobulbar haematoma. There may be an afferent pupillary defect.

X-ray if there is bony tenderness or clinical evidence of orbital or facial bone fracture.

Any patient suspected of a retrobulbar haematoma requires an emergency lateral canthotomy. This should be performed by an ophthalmologist or a trained emergency physician, under local anaesthetic in the ED, and reduces the retro-orbital pressure.

Nurse patients with obvious globe injury head up at 45°. Refer urgently.

Provide prophylactic oral antibiotics (eg co-amoxiclav) for uncomplicated facial or orbital fractures, and arrange for maxillofacial follow-up, with advice to avoid nose-blowing in the meantime.

Suspect intraocular foreign body if there is a history of hammering or work involving metal on metal. Find out if protective glasses were worn. Ascertain whether a small foreign body travelling at speed may have penetrated the orbit (eg during grinding, hammering, chiselling). Failure to suspect and diagnose these injuries can have serious consequences.

Give analgesia, tetanus prophylaxis, IV antibiotics (eg 1.5g cefuroxime), and refer all patients with penetrating eye injuries immediately to an ophthalmologist, even if there are other major injuries needing attention at the same time.

Never manipulate or try to remove embedded objects (eg darts).

The typical history is of dust or grit blown into an eye by the wind. The FB usually gravitates into the lower fornix—remove with a cotton bud.

FBs may not gravitate into the lower fornix, but may remain stuck under the upper eyelid. The patient reports pain on blinking. Fluorescein staining reveals characteristic vertical corneal abrasions (the cornea has been likened to an ‘ice rink’). Evert the upper eyelid and remove the FB with a cotton bud. Discharge with topical antibiotic (eg chloramphenicol ointment qds or fusidic acid eye drops).

Often result from a newspaper or fingernail in the eye. Irritation, photophobia, and lacrimation occur. Use LA drops and fluorescein staining to examine the cornea. Exclude FB or penetrating injury. Prescribe regular antibiotic ointment (eg chloramphenicol) and oral analgesia. An eye patch which seals eyelids closed will aid the symptoms and recovery. If the patient is very uncomfortable, consider instilling a drop of 1% cyclopentolate to dilate the pupil (this reduces iris spasm) or a drop of 0.1% diclofenac. Advise the patient not to drive until vision has returned to normal. Advise also to return for review if symptoms continue beyond 36hr.

Instill LA and attempt removal with a cotton bud. If unsuccessful, remove with a blue (23G) needle introduced from the side (ideally using a slit lamp). Ensure that the patient's head is firmly fixed and cannot move forwards onto the needle: it can help for the operator's hand to rest lightly on the patient's cheek. After complete removal of the FB, check that the anterior chamber is intact, instill and prescribe antibiotic ointment, and advise the patient to return if symptomatic at 36hr. Refer patients with large, deep or incompletely removed FB, or if a rust ring remains.

Exposure to ultraviolet light can cause superficial keratitis. Climbers/skiers, welders, and sunbed users who have not used protective goggles develop pain, watering, and blepharospasm several hours later. LA drops allow examination with fluorescein staining, revealing multiple punctate corneal lesions. Consider instilling a drop of 1% cyclopentolate or 0.1% diclofenac into both eyes. Discharge with an eye pad, oral analgesia, and advice not to drive until recovered. Anticipate resolution within 24hr. Do not discharge with LA drops.

Chemical burns from alkali or acid are serious. Triage urgently ahead, check Toxbase and provide immediate eye irrigation with lukewarm normal saline for at least 20min, or until the pH of tears has returned to normal (7.4). A 1L bag of 0.9% saline with standard IV tubing is ideal. LA may be needed to enable full irrigation. Identify the substance involved and contact Poisons Unit. Refer alkali and acid burns immediately.

Wash with warm water. The eye will open within 4 days. If the patient reports a FB sensation, this may represent a lump of glue, which may cause an abrasion if left untreated: refer to the ophthalmologist.

Contact lenses are of two basic types: hard or soft. Soft lenses, composed of hydrogels, are more comfortable to wear. Avoid using fluorescein with contact lenses, as permanent staining may occur.

Most contact lens users are adept at removing their contact lenses. New users, however, not infrequently experience difficulty in their removal. Moisten soft lenses with saline, then remove by pinching between finger and thumb. Special suction devices are available to help remove hard lenses.

Patients may present concerned that they are unable to find their contact lens and cannot remember it falling out. Check under both eyelids carefully (evert the upper lid if the lens is not immediately apparent) and remove the offending lens, if present.

Preservatives in lens cleaning fluid cause itching and may evoke a reaction. Advise to stop using the lenses, give local antibiotic ointment and arrange ophthalmological follow-up.

This is a protozoal infection of the cornea which occurs in contact lens users, associated with poor lens hygiene or swimming whilst wearing contact lenses. The eye becomes painful and red. Corneal oedema and ulceration develops. If acanthamoeba infection is suspected, refer immediately for ophthalmological care.

Treat and refer conjunctivitis, corneal abrasions, or ulcers apparently related to contact lenses as outlined opposite. Advise avoidance of use of both contact lenses until the problem has resolved.

Sudden visual loss requires emergency assessment and treatment.

The patient describes temporary loss of vision in one eye, like a ‘curtain coming down’, with complete recovery after a few seconds to minutes. The cause is usually a thrombotic embolus in the retinal, ophthalmic, or ciliary artery, originating from a carotid atheromatous plaque. Refer urgently to the ophthalmology team.

The central retinal artery is an end artery. Occlusion is usually embolic (check for atrial fibrillation and listen for carotid bruits), causing sudden painless ↓VA to counting fingers or no light perception. The patient may have a history of amaurosis fugax. Direct pupil reaction is sluggish or absent in the affected eye, but it reacts to consensual stimulation (afferent pupillary defect). Fundoscopy reveals a pale retina, with a swollen pale optic disc and ‘cherry red macula spot’ (the retina is thinnest here and the underlying choroidal circulation is normal). Retinal blood vessels are attenuated and irregular: there may be ‘cattle-trucking’ in arteries.

by digitally massaging the globe for 5–15sec then release and repeat to dislodge the embolus, whilst awaiting the urgent arrival of an ophthalmologist.

If there is any delay in the patient being seen by the ophthalmologist, consider (and discuss) the following options:

This is a more frequent cause of sudden painless visual loss than arterial occlusion. Predisposing factors include: old age, chronic glaucoma, arteriosclerosis, hypertension, polycythaemia. Examination reveals ↓VA, often with an afferent pupillary defect. Fundoscopy reveals a ‘stormy sunset’ appearance: hyperaemia with engorged veins and adjacent flame-shaped haemorrhages. The disc may be obscured by haemorrhages and oedema. Cotton wool spots may be seen. Although the outcome is variable and there is no specific treatment, refer urgently as the underlying cause may be treatable, thus protecting the other eye.

Inflammation of the posterior ciliary arteries causes ischaemic optic neuritis and visual loss. It is relatively common in those aged >50 years and is associated with polymyalgia rheumatica. The other eye remains at risk until treatment is commenced. Rapid and profound visual loss may be preceded by headaches, jaw claudication, general malaise, and muscular pains. The temporal arteries are characteristically tender to palpation. Retinal appearances have been termed ‘pale papilloedema’: the ischaemic disc is pale, waxy, elevated and has splinter haemorrhages on it. If suspected, give 200mg IV hydrocortisone immediately, check erythrocyte sedimentation rate (ESR) (typically >>40mm/hr, but can be normal) and refer urgently.

Occurs in diabetics with new vessel formation, in bleeding disorders and in retinal detachment. Small bleeds may produce vitreous floaters with little visual loss. Large bleeds result in painless ↓↓VA, an absent red reflex and difficulty visualizing the retina. Refer urgently. Meanwhile, elevate the head of the bed to allow blood to collect inferiorly.

Occurs in myopes, diabetics, the elderly and following trauma. The rate of onset is variable: patients may report premonitory flashing lights or a ‘snow-storm’, before developing cloudy vision. There may be a visual field defect. Macular involvement causes ↓VA. The affected retina is dark and opalescent, but may be difficult to visualize by standard ophthalmoscopy. Refer urgently for surgery and re-attachment.

Usually presents in a young woman. Optic nerve inflammation causes visual loss over a few days. Pain on eye movement may occur. An afferent pupillary defect is associated with ↓VA, ↓colour vision (colour red looks faded) and normal/swollen optic disc. Most recover untreated, later some develop multiple sclerosis. Refer to the ophthalmologist.

Patients with chronic visual loss due to a variety of conditions may present acutely (senile macular degeneration, glaucoma, optic atrophy, cataract, choroidoretinitis). Drugs which can cause painless visual loss include methanol (  p.202) and quinine (in overdose). Refer immediately all patients in whom an acute visual loss cannot be excluded.

Patients commonly present with a red eye with no history of trauma, but it is critical not to miss certain diagnoses. Refer all patients with new findings of ↓VA, abnormal pupil reactions, or corneal abnormalities.

This is a major infection of the orbital tissues. The infection is most frequently spread from the paranasal sinuses (ethmoid sinusitis), facial skin or lacrimal sac. Occasionally, the infection follows direct trauma to the orbit or from haematogenous spread. Patients present with fever, eyelid swelling, erythema, and proptosis. Always assess patient for signs of severe sepsis ( Severe sepsis and shock, p.59) and resuscitate as necessary. Obtain venous access, take blood for cultures, commence intravenous antibiotics (eg co-amoxiclav) and fluids. Refer urgently to the ophthalmologist. Some aggressive infections may require surgical treatment. Cavernous sinus thrombosis and meningitis are potential complications.

A relapsing condition of the young and middle-aged associated with ankylosing spondylitis, ulcerative colitis, sarcoid, AIDS, and Behçet's syndrome.

Acute onset pain, photophobia, ‘floaters’, blurred vision and watering.

↓VA, tender eye felt through the upper eyelid, circumcorneal erythema, small pupil (may be irregular due to previous adhesions). Shining a light into the ‘good’ eye causes pain in the other. Pain ↑ as eyes converge and pupils react to accommodation (Talbot's test). Slit lamp may reveal hypopyon and white precipitates on the posterior cornea.

urgently to the ophthalmologist for steroid eye drops, pupil dilatation, analgesia, investigation, and follow-up.

Long-sighted middle-aged or elderly with shallow anterior chambers are at risk. Sudden blocked drainage of aqueous humor into the canal of Schlemm causes intra-ocular pressure to increase from 10–20mmHg up to 70mmHg. This may be caused by anticholinergic drugs or pupil dilatation at night (reading in dim light).

preceding episodes of blurred vision or haloes around lights due to corneal oedema. Acute blockage causes severe eye pain, nausea/vomiting.

↓VA, hazy oedematous cornea with circumcorneal erythema and a fixed semi-dilated ovoid pupil. The eye feels tender and hard through the upper eyelid. Measure intraocular pressure if this facility is available.

Instill a 4% pilocarpine drop every 15min to produce ciliary muscle contraction and aqueous humor drainage. Apply prophylactic 1% pilocarpine drops into the other eye also. Give analgesia (eg morphine IV with anti-emetic). Arrange an emergency ophthalmology opinion: consider giving acetazolamide 500mg IV (to ↓intra-ocular pressure) meantime and/or mannitol 20% up to 500mL intravenous infusion over 1hr.

Caused by bacteria (Strep. pneumoniae or H. influenza), viruses (adenovirus), or allergy. The sensation of a FB may involve both eyes. The conjunctiva is red and inflamed, sometimes with eyelid swelling. VA and pupils are normal. Bacterial infection classically produces sticky mucopurulent tears, viral infection copious watery tears (associated with photophobia and pre-auricular lymphadenopathy in the highly contagious adenoviral ‘epidemic keratoconjunctivitis’). Prescribe antibiotic eye drops or ointment (eg fusidic acid, chloramphenicol, or gentamicin) regularly for 5 days. Advise not to share towels or pillows. Most cases settle relatively quickly: advise patients to return if symptoms do not improve within 4 days.

Corneal ulceration causes pain with photophobia. It is apparent on fluorescein staining under a slit lamp.

Whatever the infective agent, refer corneal ulceration immediately.

Inflammation beneath one area of the conjunctiva is usually associated with a nodule and a dull aching discomfort. VA, pupils, and anterior chamber are normal. Prescribe oral NSAIDs and advise outpatient follow-up to consider steroid eye drops if there is no resolution.

This chronic problem is quite common. Eyelashes are matted together and itchy. Ensure that there is no associated corneal ulceration, provide topical antibiotics (eg chloramphenicol) and refer for GP follow-up.

Treat staphylococcal infections of eyelash roots with antibiotics drops.

A chalazion is an inflammatory reaction in a blocked meibomian gland, which may become secondarily infected. Treat infected tarsal (meibomian) glands with topical antibiotics (eg chloramphenicol) together with oral antibiotics (eg co-amoxiclav). Refer patients who develop an abscess or nodule affecting vision.

Acute infection of the lacrimal sac may follow nasolacrimal duct obstruction. Treat early infections with oral antibiotics (co-amoxiclav); later, refer for drainage.

This usually presents as a painless, well-defined area of haemorrhage over the sclera. May result from vomiting or sneezing. Following trauma, consider orbital or base of skull fracture and treat accordingly.