Ophthalmology : Acute ophthalmology

Red eye: the conjunctiva

The red eye is a common complaint presenting to primary care and emergency eye clinics. Most do not have a sight-threatening cause; however, one must be alert to the ‘red flag’ signs to recognize those that do.

Aims

• Identify the common causes of red eye.
• Recognize the sight-threatening causes of red eye.
• Understand when topical antibiotics and antivirals may be helpful.

Abnormal pupil shape

• A tear drop or misshapen pupil in the context of ocular trauma, however mild, is highly suggestive of penetrating ocular trauma or a severe blunt injury which has torn the pupil fibres or the iris root (insertion into the white sclera).

• A misshapen pupil in an acutely red eye without a history of ocular trauma suggests that posterior synechiae are present (the pupil is stuck to the lens behind.) This is highly suggestive of acute or recurrent inflammation as in anterior uveitis.

• A mid-dilated and fixed pupil in the context of a painful red eye is highly suggestive of acutely raised intraocular pressure (e.g. in acute glaucoma).

Cloudy cornea

• You should be able to see the iris and pupil clearly through the cornea.

• There are many and varied causes of a cloudy cornea (infection as in contact lens ulcers, inflammation as in herpes-associated disciform keratitis, raised intraocular pressure, chemical injury etc.), and whilst it is not necessary to know why, you must seek expert ophthalmic advice promptly.

Marked visual loss or photophobia

• Photophobia is the predominant symptom in anterior uveitis and should be referred for an ophthalmic specialist opinion.

The conjunctiva

Infective conjunctivitis

Infective conjunctivitis is common and self-limiting in the majority of cases. Bacterial infections are more common in children (70–85%). Bacterial infections account for one-thirds to two-thirds of adult infections.

• Symptoms: red eye (usually bilateral), watering, discharge, itching or burning, crusting of the lid margins and general flu-like symptoms.
• Signs: diffuse redness across the conjunctiva and especially the tarsal conjunctiva (posterior surface of the lid); mucopurulent discharge.
• Management: hygiene advice (eye bathing and avoidance of towel sharing); topical antibiotics are not usually necessary as simple infective conjunctivitis is usually self-limiting, even in bacterial cases; topical lubricants will soothe and ease the itch; may take several weeks to resolve.

Special considerations

Chlamydial conjunctivitis

This is an oculogenital infection caused by serotypes D–K of Chlamydia trachomatis. It should be suspected in adults with a chronic non-resolving conjunctivitis with or without a history of venereal disease. Treatment with a tetracycline or azithromycin oral antibiotic is indicated, and patients should be referred to the genito-urinary medicine
department for investigation and contact tracing.

Allergic conjunctivitis

Allergic conjunctivitis is common, affecting approximately 20% of the population, and it is commoner in atopic individuals. It may be acute and a type 1 hypersensitivity disorder, as in seasonal and perennial allergic conjunctivitis, or chronic with type 1 and 4 hypersensitivity reactions, as in vernal and atopic keratoconjunctivitis.

• Symptoms: itch (predominant symptom), watering.
• Signs: bilateral pink or red eyes, eyelid oedema, conjunctival swelling (chemosis) may be dramatic.

Subtypes

• Seasonal allergic conjunctivitis (hay fever): allergens usually include tree and grass pollen; occurs in the spring and summer.
• Perennial allergic conjunctivitis: allergens include house dust mites and animal dander (skin scales); year-round symptoms.
• Vernal allergic conjunctivitis: primarily affects young boys in first decade of life; strong association with atopy; most cases remit by adulthood, with 5–10% persisting as atopic keratoconjunctivitis.
• Atopic keratoconjunctivitis: uncommon; chronic and unremitting; adults usually have a history of childhood atopy and vernal allergic conjunctivitis.

Giant papillary conjunctivitis

A response to mechanical trauma, this is traditionally induced by long- term soft contact lens wear but may occur in association with ocular prosthesis, filtering blebs created by glaucoma surgery and exposed sutures.

Management of allergic eye disease

• Mast cell stabilizers.
• Antihistamines (oral and topical).
• Topical steroids may be indicated in severe cases, but ophthalmic advice should be sought.
• Vernal and atopic keratoconjunctivitis require specialist ophthalmic care. Some patients require systemic immunosuppression.

Stevens–Johnson syndrome

• Uncommon potentially lethal condition with severe ocular morbidity.
• Type IV hypersensitivity reaction.
• Triggers include infections (mycoplasma, HSV, mycobacteria, Grp A streptococci, and others), drugs (sulphonamides, barbiturates, penicillins, anti-epileptics and antiretrovirals), malignancy and idiopathic.
• Acute disease usually associated with crusty lids and a transient self-limiting conjunctivitis. Membranes may form on the inner surface of the lids.
• Late disease is associated with marked dry eye as the goblet cells and lacrimal gland ductules are destroyed. This may lead to breakdown of the corneal and ocular surface, scarring, symblepharon formation (permanent adhesion of the conjunctiva in the depths of fornices of the lids to the globe), aberrant and misdirected lashes, entropian
  and corneal stem cell failure causing blindness.

Subconjunctival haemorrhage

• Painless localized dense red haemorrhage on the surface of an otherwise normal eye.
• Common and self-limiting (resolves in 10–14 days).
• Sudden onset and often incidental finding.
• Some evidence indicates that it is more common in systemic hypertension.
• Routine investigation for coagulopathies is not indicated unless there is evidence and clinical suspicion of other bleeding sites.

Red eye: the cornea

A complete examination of a red eye involves instilling fluorescein drops either in 2% form or mixed with a local anaesthetic drop such as proxymetacaine and illuminating the ocular surface with cobalt blue light. This allows you to see pathology not visible under white light, namely, disruption of the corneal surface including abrasions, ulceration
and corneal and conjunctival epithelial disturbance.

Corneal abrasions

• Corneal abrasions (scratches) occur when the surface layer of the corneal epithelium is disturbed, usually by trauma (e.g. finger poking, or a tree branch or bamboo stake in the eye).
• Corneal abrasions are extremely painful but usually resolve after 48 h.
• Fluorescein staining reveals an epithelial defect under cobalt blue light.
• Upper lid eversion and careful examination of the upper and lower fornices are advised to look for retained foreign bodies.
• Topical chloramphenicol drops or ointment is usually prescribed. An eye pad is not necessary. Topical anaesthetic to take away is contraindicated.
• In severe cases, the patient may develop recurrent corneal erosion syndrome where the new corneal epithelium re-opens or sloughs off repeatedly, causing recurrent pain, foreign body sensation and mildly blurred vision. These cases should be referred for specialist management. The aetiology is often a sharp injury from a baby’s fingernail,
  sharp-leafed plant or edge of paper. An underlying corneal dystrophy is a rare underlying cause.

Corneal infections

• Serious corneal infections are usually seen in contact lens wearers, in farmers or gardeners where unusual organisms such as fungi or Acanthamoeba should be suspected, in cases of herpes simplex or zoster and in patients where there is disruption to normal corneal innervation causing reduced or absent corneal sensation.

Contact lens keratitis

• A unilateral painful red eye in a contact lens wearer is highly suspicious for a contact lens ulcer or keratitis.
• Some bacterial pathogens are aggressive and can cause corneal perforation (e.g. Pseudomonas aeruginosa).

Symptoms

• Unilateral red eye.
• Pain and photophobia.
• Tearing.
• Contact lens over-wear or unintentional overnight wear.

Signs

• Unilateral red eye.
• You may see a white spot on the cornea with the naked eye.
• Fluorescein staining reveals an epithelial defect under cobalt blue light.

Management

• Urgent ophthalmic opinion.
• Corneal scrape for urgent Gram staining; microscopy and culture for bacteria, fungi and Acanthamoeba.
• Contact lens wear break.
• Frequent topical antibiotics, usually a quinolone such as ofloxacin or levofloxacin.

Acanthamoeba keratitis

• Acanthamoeba spp. are found in soil, fresh or brackish water and the upper respiratory tract.
• A. keratitis causes serious corneal infections in contact lens wearers (especially if they rinse their lenses in tap water) and in agricultural workers who sustain soil-contaminated corneal injuries.
• A. keratitis should be suspected in one of these at-risk groups where the pain and visual disturbance are out of keeping with the clinical signs.
• Classical signs include ring infiltrates and perineural infiltrates.
• Special culture media such as an Escherichia coli-seeded non-nutrient agar plate are required to grow the organism, or the amoebic cysts can be seen in the cornea with laser confocal microscopy.
• Treatment is continued for months as viable organisms can encyst and lie dormant in the cornea only to reactivate in the future.
• Topical amoebicides include propramidine isethionate 0.1% (Brolene), polyhexamethylene biguanide 0.02% drops, hexamindine and chlorhexidine.

Dendritic ulcers

• Herpes simplex virus (HSV) detection by polymerase chain reaction in the trigeminal ganglion is almost 100% in people over the age of 60, yet only 20–25% of individuals with HSV antibodies have a clinical history of the disease.
• HSV can cause a characteristic branching tree-like ulcer on the cornea known as a dendritic ulcer.
• HSV lies dormant in the trigeminal ganglion but can be reactivated to cause recurrent corneal ulceration.
• In the longer term, the corneal sensation may be reduced or absent, and this is associated with long-term scarring, melting, vascularization and failure of the cornea.
• Corneal sensation should be checked and compared with the fellow eye before fluorescein and topical anaesthetic drops are instilled.

Management

• Topical acyclovir 3% ointment five times daily.
• Alternatives include trifluorothymidine, vidarabine and ganciclovir.

Pterygium

• A pterygium is a triangular or wedge-shaped growth of conjunctival tissue onto the cornea.
• It is thought to be more common in individuals with high ultraviolet light exposure.
• In most cases it does not interfere with vision, but where it encroaches on the central vision or distorts the shape of the eye, causing astigmatism, it can be treated surgically.
• It may become inflamed periodically, and topical lubricants or nonsteroidal or steroid drops may be necessary.

Red eye: the sclera and episclera

The wall of the globe consists of three main layers:

• Conjunctiva: the outer transparent mucous membrane of the globe. It also lines the inner surface of the lids and forms the depths or fornices of the lids. The conjunctiva contains blood vessels, lymphatics, mucus producing goblet cells, accessory lacrimal glands (glands of Krause and Wolfring) and lymphoid tissue.

• Episclera: a middle layer of connective tissue and blood vessels.

• Sclera: the white inner coat of the eye. It is composed of collagen bundles.

Episcleritis

This is a common, benign and recurrent condition where the episcleral tissue becomes inflamed. It is usually idiopathic and self-limiting, although speed of resolution can be enhanced with topical or oral anti-inflammatories.

Presentation

Commonly unilateral, but there may be bilateral, sectorial redness of the eye. It is usually seen in the temporal or nasal quadrants of the eye, but may occasionally be diffuse through 360°. It is uncomfortable but not very painful. When a patient has severe pain, scleritis is more likely.

Treatment

Very mild episcleritis may not require any treatment.

• Lubricants.
• Topical non-steroidal anti-inflammatory drugs (NSAIDs) (e.g. ketorolac 3× daily).
• Oral NSAIDs (check for contraindications) ibuprofen, flurbiprofen or diclofenac.
• Topical mild steroids (e.g. prednisolone 0.3% or 0.5% 3× daily for 10–14 days).

Scleritis

Scleritis is much less common than episcleritis. It may be mild and self-limiting or severe, extremely painful and sight threatening.

It is commonly classified into anterior and posterior disease and as necrotizing or non-necrotizing.

There is an associated systemic condition in 33–50% of scleritis, such as:

• rheumatoid arthritis
• systemic vasculitides
• Wegener’s granulomatosis, more recently renamed granulomatosis with polyangiitis
• systemic lupus erythematosis
• seronegative spondyloarthropathies.

It is also associated with infection, especially tuberculosis and syphilis; trauma, including surgical trauma; and malignancy, such as lymphoma.

Signs

• Intense redness of the scleral and episcleral vessels.
• Tender globe to touch.
• Scleral necrosis in necrotizing disease, scleromalacia. The black-blue hue of the choroidal tissue is seen as the white scleral tissue disintegrates.

Management

The traditional treatment algorithm involves:

• NSAIDS.
• Local depot steroid injections (e.g. orbital floor or subconjunctival steroid).
• Oral steroids 1–2 mg/kg/day.
• Cytotoxic agents (e.g. cyclophosphamide, methotrexate and azathioprine).
• Biologic agents (e.g. anti-CD20 (Rituximab)).

In addition:

• Seek out and manage associated systemic conditions.
• Systemic immunosuppression is often required.
• Specialist management is required in most cases.

Ophthalmic trauma principles and management of chemical injuries

Managing simple eye trauma is a basic requirement for a casualty officer. Knowing how to manage more complex trauma requires you to identify the extent of the eye trauma, stabilize it and know when and to whom to refer the patient.

Aims

• List the main causes of loss of vision due to trauma.
• Know how to wash out a chemical injury.

Principles of ophthalmic trauma

The ophthalmic trauma patient may be managed by the ophthalmologist alone or by the ophthalmologist working in a team with the plastic, maxillofacial or neurosurgeon, if there are associated severe facial and head injuries.

Trauma can affect the periocular region, bony orbit, orbital contents, globe or optic nerve

• Eyelid and periocular and orbital haematoma—fully assess to rule out orbital floor fracture and fracture of base of skull.
• Orbital bony wall fracture—floor > medial wall with diplopia; needs repair.
• Eyelid sub-tarsal foreign body—evert lid and remove with cotton bud.
• Eyelids—partial or full thickness laceration: explore wound, exclude penetrating eye injury and repair within 48 h.
• Lacrimal drainage system—most commonly lower canaliculus; needs oculoplastics repair and stent (e.g. MiniMonaka tube).
• Conjunctival laceration—may need suturing; exclude more extensive deeper injury.
• Corneal abrasion—treat with topical antibiotics ± cycloplegia and an eye pad.
• Corneal foreign body—needs removal and dilated fundoscopy.
• Corneal penetrating injury ± sclera, iris, lens or retinal injury— all require urgent surgical repair.
• Hypahaema (blood in the anterior chamber)—can cause secondary glaucoma; needs urgent ophthalmic assessment.
• Dislocated lens—may need surgery to remove lens.
• Traumatic cataract—most need surgical removal.
• Glaucoma secondary to angle recession (i.e. damage to trabecular meshwork)—needs specialist treatment.
• Blunt vitreous haemorrhage and retinal commotio—needs vitreo- retinal assessment to exclude retinal tear.
• Retinal tear or dialysis—needs urgent retinal surgery.
• Choroidal rupture—may lose vision if it underlies the macula; untreatable.
• Scleral perforation—needs surgical exploration and repair; if extensive, patient may lose eye (enucleation).
• Massive retrobulbar haemorrhage—needs urgent lateral canthotomy or cantholysis to decompress orbit.
• Traumatic optic neuropathy—needs to be treated with high-dose steroids within hours.
• Traumatic cranial nerve injury—IVth, IIIrd and VIth cranial nerves need magnetic resonance imaging scan.
• Complete globe disruption—needs enucleation within 14 days to prevent sympathetic ophthalmia.

Chemical injuries

Which chemical? Substances include alkalis (lime, cement, plaster or ammonia), acids, solvents, detergents, irritants (e.g. mace and pepper) and super glue. Alkalis (e.g. ammonia or wet cement) are the most destructive, penetrating the deep layers of the eye with time. In high concentrations, they cause severe ischaemia of the conjunctiva, corneal
limbus, cornea and sclera, and cause subsequent scarring and blindness. There may be associated severe uveitis and cataract formation.

How to manage a patient with a suspected chemical eye injury

1 Wash out the eye immediately.
2 Measure the pH of the tear meniscus if litmus paper is handy.
3 Otherwise, apply immediately topical anaesthetic drops if handy.
4 Copious irrigation with normal saline or Ringer’s solution. If neither is available, put the patient’s head under a cold water tap or into a bowl of cold water—with the eyes open! Irrigate or splash the eyes for 5–10 min, then repeat the pH measurement.
5 Ensure that the surface of the eye and the upper and lower fornices are included. Using a cotton bud, evert the upper lid, check for fragments of cement and the like and remove them. Swipe the cotton bud along the lower fornix to remove particulate debris.
6 Now measure the visual acuity and check the eye, including the intraocular pressure (IOP).
7 Admit.
8 Topical treatment: intensive topical antibiotics, vitamin C and cycloplegia (to prevent pain) ± steroids. Treat raised IOP as necessary.
9 Oral high-dose vitamin C.
10 Later surgery if needed—limbal cell transplant and penetrating keratoplasty (corneal graft).

Specific features of blunt and sharp injuries

Aims

• Know how to manage a retrobulbar haemorrhage; remove a corneal foreign body (FB); and manage a corneal abrasion.

Blunt injuries

Aetiology

From a fist; cricket, squash or tennis ball; champagne cork or the like.

Findings

Lid ecchymosis, orbital and subconjunctival (Figure 17.2) haemorrhage, hyphaema, lens injury, orbital floor fracture , vitreous haemorrhage and commotion retinae.

Systematic examination

Front (eyelids) to the back (retina) including the orbit. Exclude a perforating ocular injury. Exclude an orbital floor fracture by examining the eye movements, particularly restriction of up-gaze, and look for infra-orbital numbness. Examine the cornea and conjunctiva for FBs abrasions and lacerations. Use fluorescein drops to visualize corneal
abrasions. Examine the fundus.

Blunt injury: traumatic hyphaemia

Blood in the anterior chamber. Often microscopic and only detected on the slit lamp or forms a fluid level easily seen with a pen torch. If blood fills the entire anterior chamber—‘blackball hyphaemia’.
Management: If the posterior segment of the eye cannot be seen easily, do an ultrasound for vitreous, supra- or sub-retinal haemorrhage; Steroid and dilating drops minimize inflammation and re-bleeding. Surgical washout of blood is rarely required except in blackball hyphaemia with intractably raised intraocular pressure.

Traumatic iritis

Inflammation in the anterior chamber (AC) of the eye seen as white cells and flare on the slit lamp. Common even after minor blunt trauma to the globe causing symptoms of pain, photophobia and blurred vision.
Management: Treat with topical steroid and mydriatic drops.

Orbital haematoma

Eyelid ecchymosis. Test consensual pupillary reflex by shining a bright light through the bruised lid to confirm that the afferent pathway is working. With established eyelid bruising, it is difficult to open the eyelids and examine without using topical anaesthesia and fingers to prise open the lids. Measure the visual acuity, examine the eye movements,
exclude a perforating injury and look at the fundus.

Commotio retinae (CR) or ‘retinal bruising’

The retina is opaque. If the central retina or macula is affected, the vision can be blurred. CR usually resolves fully.

Traumatic optic neuropathy

Associated with severe head trauma and multiple injuries. Prognosis for visual recovery is poor when a marked afferent pupillary defect.
Management: Conservative. High-dose intravenous steroids have not demonstrated significant benefit for visual recovery.

Orbital floor fracture

Blow-out fracture of the floor or medial wall into the sinus. Orbital tissue entrapment may cause diplopia and limited eye movements. Exophthalmic often after swelling has settled.
Management: If there is painful restriction of up gaze, do urgent orbital floor repair. If there are persistent restrictive eye movements or enophthalmos after one week, do orbital floor repair.

Sharp, penetrating and perforating injuries

Aetiology

Sharp objects (e.g. glass, spiky plants, hammer and chisel, or fish hooks) cause eyelid, corneoscleral, iris, lens and retinal lacerations.

Findings

The entry wound may be tiny and a high index of suspicion is required in all high-velocity injuries for the presence of an interocular FB (IOFB). Misshapen pupils suggest penetrating injury. Perforating injuries require urgent exploration under general anaesthesia to assess the full extent of the injury and to do the micro-surgical repair.

Superficial corneal injuries

Corneal FBs and sub tarsal FBs (STFBs) are common. The patient often gives a history of dust, metal or an insect entering the eye.
Symptoms: Painful photophobic red watering eye, sensation of FB on eye or under eyelid, often completely relieved on the instillation of topical local anaesthetic.
Signs: Corneal FB on the corneal epithelium seen with a pen torch or slit lamp; STFBs are found on the tarsal conjunctiva when the upper lid is everted, and they typically cause repeated vertical streak corneal
abrasions with repeated blinking.

Corneal abrasion

History of scratch from a sharp plant, paper, fingernail or the like.
Symptoms: Severe pain and FB sensation, photophobia and watering.
Signs: Red eye, fluorescein staining of the epithelial defect in cobalt blue light. Corneal abrasions are very painful but heal quickly. When from a very sharp object, recurrent erosion syndrome (RES) can develop where the new epithelial cells do not adhere well to the underlying stroma and repeatedly slough off. This is treated with lubricating
drops and ointment before sleeping.
Examination: Topical anaesthesia and fluorescein to demonstrate a corneal abrasion; In all cases, the upper lid must be everted to look for a retained STFB.
Management: Wipe off the corneal or sub tarsal FB with a cotton bud, or tip of an orange needle to scrape or flick the FB off; Prescribe topical chloramphenicol drops 4× daily for 5 days. A pad is not necessary. With marked pain and photophobia, cyclopentolate 1% may be used 3× daily. Do not prescribe topical anaesthesia to take home.

Corneal laceration

A corneal laceration can be self sealing but usually requires microscopic suturing and exploration.

Loss of vision in the inflamed eye

Uveitis is inflammation of the uveal tract and can be anterior, intermediate or posterior. It can give blurred vision and lead to loss of vision.

Aims

1 Characterize and diagnose the types of uveitis.
2 Know the most common causes of inflammation in the eye affecting the vision (e.g. scleritis).

We classify ocular inflammation anatomically: for instance, anterior uveitis is inflammation of the iris, retinitis is inflammation of the retina, scleritis is inflammation of the sclera and episcleritis is inflammation of the episcleral.

Uveitis

• Acute anterior uveitis (AAU): inflammation of the iris and ciliary body.
  ○ Symptoms: Acute onset pain, photophobia and secondary watering. Exception: juvenile idiopathic arthropathy (JIA) anterior uveitis is painless.
  ○ Signs: Red eye with conjunctival circumciliary injection (around the limbus;), kerato precipitates (white blood cells (WBC) on the corneal endothelium), posterior synechiae (inflammatory cells causing adhesions between the lens and iris) and cells and flare in the anterior chamber (corresponding to WBC and proteins following the breakdown of the blood–iris barrier); seen on the slit lamp.

• Intermediate uveitis: inflammatory signs in the vitreous
  ○ Symptoms: floaters, blurred vision, without pain.
  ○ Signs: vitreous cells, snowballs (pre-retinal inflammatory aggregates), snow-banking (pars plana exudation), and macular oedema.

• Posterior uveitis
  ○ Can be a chorioretinitis, affecting both the chorid (uvea) and the adjacent retina.
  ○ Symptoms: Painless blurring of vision, with floaters and photopsia (flashing light).
  ○ Signs: variable cells in the anterior chamber and vitreous, choroiditis (fluffy, raised lesions without pigment if active), retinitis (cotton wool spots, haemorrhages and cuffing, attenuation or dilatation of vessels), macular oedema and exudative retinal detachment.
  ○ Specific inflammatory disorders that target the choroidal tissue are known as the white dot syndromes.

• Pan-uveitis: affecting all the above, anterior, intermediate and posterior.

Investigations

Distinguish whether the uveitis is infective or non-infective. Sixty percent of uveitis is idiopathic, with important underlying systemic disease in the remainder.
Do baseline and specific tests: full blood count (FBC); urea and electrolytes (U&E); chest X-ray (CXR); angiotensin-converting enzyme (ACE); human leukocyte antigen tests (HLA-B27 and HLAA29); syphilis (Venereal Disease Research Laboratory (VDRL) test); enzyme-linked immunosorbent spot (ELISPOT) assay; lyme serology; antinuclear antibody (ANA) test and anti-neutrophil cytoplasmic antibodies
(ANCA) test.

Management

All idiopathic causes of uveitis are treated as non-infective.

Infective

• If the cause of the inflammation is infective, the most appropriate antimicrobial should be used.
• Note the Jarisch–Herxheimer reaction, an inflammatory reaction against massive bacterial lysis once antimicrobials commence, particularly with syphilis and tuberculosis, which can be reduced with corticosteroids added to the antimicrobials.

Non-infectious

• Corticosteroids applied topically, peri-ocularly, orally or intravenously. Liaise with the physicians to help control patients’ uveitis with steroid- sparing agents.
• Advances in nanotechnology of sustained-release implants placed directly in the vitreous deliver local steroid to the back of the eye, thus negating problems of poor safety profile and reduced bioavailability of oral steroids due to the blood–retinal barrier (choriocapillaris).

Posterior scleritis

• Symptoms: anterior scleritis (diffuse, nodular or necrotising) has typical deep injection (redness) and pain. In posterior scleritis, the eye is often white but the posterior sclera is thickened, thus leading to visual loss. Severe pain not helped by analgesia, ocular tenderness, diplopia and painful eye movements, due to a combination of extraocular muscle insertion on inflamed sclera and inflammation of the muscles (myositis).

• Examination: dilated fundoscopy to exclude exudative retinal detachments, uveal effusions, choroidal folds and disc oedema; B-scan ocular ultrasonography to show thickened posterior sclera and the ‘T-sign’ from fluid in Tenon’s space.

• Investigations: the underlying cause is non-infective and immune related. Investigate Rh factor, ANA, p-ANCA and c-ANCA.

• Management: nonsteroidal anti-inflammatory drugs (NSAIDs) (for non-necrotising disease) and corticosteroids, delivered topically, periocularly, orally or intravenously (all if necrotising disease is present).

Liaise with the rheumatologists to diagnose and treat an underlying systemic condition and advise if long-term steroid-sparing agents are indicated.

Advanced keratitis

An opaque cornea with severe reduction in visual acuity. Many causes and predisposing factors:

• Contact lens (CL) wear in bacterial keratitis and acanthamoeba keratitis.
• Previous herpes simplex and herpes zoster viral infections in viral keratitis.
• Patient who are from a hot, tropical country or who have experienced recent trauma in fungal keratitis.
• Loss of corneal sensation in neurotrophic keratitis. Always assess corneal sensation prior to instilling topical anaesthesia.
• The inability to close the eye (lagophthalmos) in exposure keratitis.

Treatment depends on the underlying aetiology and the patient requires regular vision monitoring in the first week following diagnosis.

Peripheral ulcerative keratitis (PUK)

This is associated with immune complex deposition in the peripheral cornea and subsequent damage to the stroma via the release of matrix metalloproteinases. Commonly due to rheumatoid arthritis and Wegener’s granulomatosis. If the cause cannot be identified, the idiopathic version is called Mooren’s ulcer. Patients will require systemic immunomodulators and may require keratoplasty.

Sudden painful loss of vision in a non-inflamed eye

An adult patient presenting with sudden loss of vision but no inflammation (i.e. has a normal-looking white eye) should be suspected of having giant cell arteritis (GCA); however, you should also exclude other causes, which are discussed in this chapter.

Aims

• Identify the main causes of sudden painful loss of vision in a white eye.
• Note that the pain may be ocular, cranial or both. Sudden loss of vision associated with eye pain or headache in the white non-inflamed eye needs urgent attention as it may be due to life-threatening illness. The frequency of each disease varies between age groups.

Giant cell arteritis or temporal arteritis

Consider this as a diagnosis if there is visual disturbance with headache in patients over the age of 50. See on GCA, and look at the visual field defect seen in anterior ischaemic optic neuropathy (AION).

See also, ‘Optic Nerve Disease’, which shows the different types of visual field defects in papilledema and pituitary tumour, and, ‘Visual Field Defects’, which shows the whole array of visual field defects in optic nerve and neurological disease.

Optic neuritis or retrobulbar neuritis

This is visual disturbance with eye pain, commonly in young adult people (particularly women). There are two clinical entities:

• Papillitis
  ○ Inflammation of the actual optic nerve head.
  ○ It appears swollen if all the nerve is affected.
• Retrobulbar neuritis
  ○ The part of the nerve behind the globe (i.e. the retrobulbar part of the nerve) is affected.
  ○ There is sparing of the nerve head.
  ○ The patient will have the same symptoms and signs of optic nerve dysfunction, including reduced visual acuity, red desaturation and a relative afferent papillary defect. However, the disc appears normal in the acute phase.
  Optic neuritis (ON) is closely linked with multiple sclerosis (MS), an inflammatory disease of the myelin sheaths in neurons of the central nervous system. Up to 50% of patients with MS will develop an episode of ON. Up to 30% of patients presenting with a first episode of ON will have underlying MS.
  Typically, patients with ON present with:
• Sudden loss of vision
  ○ Ranges from complete loss of vision to alteration in colour perception (e.g. the patient may complain of colours looking ‘washed out’ with the affected eye).
• Eye pain
  ○ Induced by eye movement.
• Other symptoms are attributable to undiagnosed demyelination, such as:
  ○ paraesthesia
  ○ bladder or bowel dysfunction
  ○ limb weakness.
  The course and treatment of ON came from the Optic Neuritis Treatment Trial in the 1990s. This was a randomized controlled trial consisting of three arms:
  1 Intravenous corticosteroids.
• 2 Oral corticosteroids.
• 3 Placebo.
• The following information was ascertained:
• There was a 28% probability of recurrence of ON in either eye in 5 years.
• Magnetic resonance imaging (MRI) of the brain is the single most important determinant of risk of developing MS by showing demyelinating plaques.
• Oral steroids are not required in isolated ON.
• Intravenous corticosteroids do have a place in clinical management, but their use is patient dependent. They may accelerate visual recovery but won’t improve visual outcome in the long term. Particularly consider if:
  ○ Vision is compromised in both eyes.
  ○ There is severe pain.
• After an episode of ON, full return of visual function is never complete. Visual recovery begins rapidly within 2 weeks in most ON without treatment, but it continues to improve for up to 1 year.

Migraine

This is visual disturbance with headache.
These visual disturbances most commonly present as fortification spectra or scintillating scotoma, but occasionally as field loss or even total loss of vision, which recovers. There is often a family history of migraine.

Idiopathic intracranial hypertension (IIH)

Patients with IIH present with headache and transient visual obscurations (TVOs). TVOs last for a few seconds, are unilateral or bilateral and are usually precipitated by movement or postural changes. They are pathognomonic of papilloedema.

• IIH occurs typically in obese females, but it can affect slim individuals of either sex as well as children.
• The optic discs are both swollen, and there is field loss.
• An MRI should be performed to exclude a space-occupying lesion and magnetic resonance angiography to exclude venous sinus thrombosis or an arteriovenous malformation affecting the venous sinuses.
• Thyroid dysfunction is a cause and must be excluded.
• Patients should be referred for urgent treatment, as this disease often results in permanent loss of the visual field.
• Treatment includes:
  ○ Conservative: weight loss; stop any medications that may cause IIH (e.g. NSAIDs or tetracyclines).
  ○ Medical: acetazolamide.
  ○ Surgical: lumbo- or ventriculo-peritoneal shunt, or optic nerve sheath fenestration.

Haemorrhage associated with pituitary tumour

Rarely, a small haemorrhage in an undiagnosed pituitary tumour can cause sudden loss of vision associated with headache.
Such patients require urgent referral to a neurosurgical unit, as this is a precursor of pituitary apoplexy.

Sudden painless loss of vision

This is an alarming event. You can usually diagnose the cause by looking at the retina with an ophthalmoscope, or by doing visual fields.

Aim

Identify the main causes of painless loss of vision, in particular:

• Vitreous or sub-retinal haemorrhage
• Retinal detachment
• Types of vascular occlusion.

Vitreous and sub-retinal haemorrhage

Haemorrhage into the vitreous cavity can result in sudden painless loss of vision. The extent of visual loss will depend on the degree of haemorrhage.

• A large vitreous haemorrhage will cause total visual loss and loss of the red reflex or severe dulling of it, without a clear retinal view.
• A small vitreous haemorrhage will present as floaters and normal or only slightly reduced visual acuity.
• A sub-retinal haemorrhage has a distinct shape and is seen as a central dark scotoma using the Amsler chart.

Aetiology

• Proliferative retinopathy
  ○ Spontaneous rupture of abnormal fragile new vessels that grow on the retinal surface cause bleeding into the vitreous cavity.
  ○ Any ischaemia can cause neovascularization, including vein occlusions.
• Retinal detachment
  ○ A small retinal blood vessel may rupture when the retinal break occurs, bleeding into the vitreous cavity.
• Trauma
• Posterior vitreous detachment
  ○ Can result in vitreous haemorrhage if, as the vitreous separates from the retina, it pulls and ruptures a small blood vessel.
• Age-related macular degeneration (AMD)—a haemorrhage may occur into the vitreous from the abnormally weak vessels
  forming a sub-retinal neovascular membrane. More often, it causes a sub-retinal haemorrhage.

Management

Referral to an ophthalmologist to determine cause and manage any complications (e.g. glaucoma due to red blood cells clogging up trabecular meshwork) that may occur. Treatment may be possible with laser or intravitreous injection.

Retinal detachment

• There are three distinctive types associated with different diseases:
  ○ Rhegmatogenous: secondary to a retinal tear.
  ○ Exudative: secondary to inflammation or vascular abnormalities.
  ○ Tractional: secondary to fibrovascular tissue caused by inflammation or neovascularization (such as proliferative diabetic retinopathy).
• All of these lead to sudden (sometimes gradual) painless loss of vision.
• Usually preceded by symptoms of flashing lights (photopsia) and/or floaters and/or visual field defects.
• When the macula is not involved (macula-on), the visual loss involves the peripheral field and visual acuity may be normal. Macula-on detachment is regarded as an emergency as surgery done before the macula detaches can result in retention of good vision.
• Once the macula is involved (macula-off), the central vision is lost.
• A macular hole can result from a vitreous detachment and have only a very small amount of sub-retinal fluid around it.
• Always take a new flurry of floaters and/or photopsia very seriously.
  These patients need indentation with indirect ophthalmoscopy to exclude peripheral retinal breaks.
• When examining these patients with retinal detachment, include looking at the anterior third of the vitreous with the slit lamp. Look for pigmented cells floating around, the so-called tobacco dust or Shaffer’s sign. By definition, if one can see the retinal pigmented cells in the vitreous, there must have been a retinal break. So, if you see tobacco dust and are unable to identify a break in the retina, you must get a senior ophthalmologist to review and locate the break.

Peripheral retinal tear

Management consists of laser to retinal hole (retinopexy) ± vitrectomy (within 24 h if macula-on). Prior to surgery, it is important to ensure the patient’s posture: if the detachment is temporal, ensure that the patient lies with the contralateral cheek to the pillow. If the detachment is in the nasal retina, ensure that the patient lies with the ipsilateral
cheek to the pillow.

Macula hole

Vitrectomy and epiretinal peel, if indicated.

Vascular occlusion

Patients with retinal vascular occlusions often present with sudden painless loss of vision.

Central retinal vein occlusion (CRVO) or branch retinal vein occlusion (BRVO)

Aetiology

• Systemic hypertension
• Raised intraocular pressure
• Hyperviscosity syndromes
• Vessel wall disease (e.g. diabetes, or inflammation such as sarcoidosis).

Central retinal artery occlusion (CRAO) or a branch retinal artery occlusion

Aetiology

• Very high intraocular pressure, usually great than 30 mmHg
• Arterial embolus from diseased carotid, valvular heart disease or atrial fibrillation
• Arterial occlusion from atheroma or inflammation (e.g. giant cell arteritis).

Non-arteritic anterior or posterior ischaemic optic neuropathy (AION or PION, respectively)

• Results from occlusion or hypoperfusion of the small blood vessels supplying the optic nerve head (AION) or posterior optic nerve (PION). See the diagram vessels and ocular cast of the circle of Haller and Zinn.
• In AION, the optic disc is swollen; this swelling may be segmental or involve the entire nerve head. There are usually associated splinter haemorrhages at the disc.
• In PION, the optic disc looks normal.
• There may be arteriosclerosis and arteriovenous nipping, depending on the cause.
• Risk factors: arteriosclerosis, hypertension, a hypotensive episode, smoking and a ‘disc at risk’ (e.g. a small optic nerve head with no central cup).

Cerebral

Cerebrovascular accident (CVA)

A haemorrhagic or thrombo-embolic CVA affecting the visual pathways will present as acute painless visual loss. Depending on the site of the lesion, the patient will have a corresponding field defect on fields to confrontation.

Acephalgic migraine

This rare form of migraine presents with transient visual disturbances involving one or both eyes in the absence of headaches.