This is a UKMLA-centred history guide about red eye.
Introduction
This article will guide you on how to approach history taking for a patient presenting with red eye.
This is a common presentation and there is an extremely wide range of differentials ranging from relatively benign such as dry eye or blepharitis, to emergencies such as acute angle closure glaucoma and endophthalmitis.
It is beyond the scope of this article to address and discuss all of the possible differentials but instead we will focus on the common & crucial ones.
Key Differentials
It would be difficult to proceed with history taking without being aware of key differentials. These are listed here to add context to the questions we will ask.
Key Differentials:
• Lid conditions – blepharitis, stye, chalazion
• Dry eye
• Subconjunctival haemorrhage
• Conjunctivitis – bacterial, viral, allergic, chemical
• Episcleritis & Scleritis
• Pingueculae & pterygium
• Corneal abrasion
• Corneal infection – bacterial, viral, fungal, amoeba
• Acute Anterior Uveitis (AAU)
• Acute Angle Closure Glaucoma (AACG)
• Endophthalmitis
Presenting Complaint
Location:
Is it unilateral or bilateral?
‣ A unilateral red eye has a wide differential.
‣ Stye, chalzion, subconjuctival haemorrhage, corneaL abrasion, anterior uveitis, glaucoma and many others!
‣ Conjuctivitis can be unilateral or bilateral, often you will get a history of the symptoms starting in one eye and spreading to the other.
‣ Bilateral red eye is more likely to indicate a systemic underlying cause.
Did it begin in one eye and then develop in the contralateral eye?
‣ This could help identify viral conjunctivitis as it often starts unilaterally and then due to cross contamination, develops in the contralateral eye.
‣ Alternatively you should consider anterior uveitis with an underlying systemic cause as it can be asymmetrical.
Is there a specific sector of the eye affected?
‣ You can split the eye into 4 quadrants to help you classify this.
‣ Alternatively consider if it is superior, inferior, nasal or temporal.
‣ Subconjunctival haemorrhages are often well defined in a region.
‣ Episcleritis and pingueculae are often sectoral and this can help identify them.
Are the eyelids involved?
‣ You should ask if the eyelids or peri-orbital region are involved as this can point to conditions such as blepharitis or allergic reaction to new drops.
‣ Furthermore existing lid conditions such as ectropion and entropion can lead to exposure dry eye or irritation from the lashes.
Onset & Timing:
When did it start?
‣ Has it gotten worse? If so, how fast (over hours, days or weeks)?
‣ It is often more concerning the more acute it is.
What day or time of day is it at it’s worst?
‣ Dry eye is usually worst at the end of the day.
‣ If it is better at the weekend consider how their job environment may be affecting their eyes – think dry eye or chemical exposures.
Consider what time of year it is.
‣ In summer a patient presenting with bilateral itchy red eyes points towards allergic conjunctivitis, whereas someone presenting with recent upper respiratory tract infection in winter means viral conjunctivitis is most likely.
‣ In summer air conditioning is used more which can exacerbate dry eye.
Exacerbating Factors & Triggers:
‣ Trauma – abrasions, if poked in the eye with vegetation/branches, consider fungal infection.
‣ Valsalva/Straining – can lead to subconjunctival haemorrhage.
‣ Recent viral infection or coryzal symptoms links to viral conjunctivitis.
‣ Chemical exposure.
‣ Foreign bodies in the eye – can cause corneal abrasions and these may get infected.
Associated Symptoms:
‣ Drop in vision – always consider their best corrected vision.
‣ Pain – severe deep boring pain is associated with scleritis. Sharp pain is linked to cluster headaches. For pain bad enough to cause nausea and vomiting (N&V) think AACG.
‣ Uveitis, slceritis and acute glaucoma are often very painful.
‣ Severe globe pain is a red flag and these patients should attend eye casualty immediately.
‣ Discomfort or Foreign body (FB) sensation – dry eye, FB or conjunctivitis are all common causes of this.
‣ Headache – think AACG or cluster headache.
‣ Discharge – think infection, characterise if it is purulent (bacterial) or watery (viral or allergy).
‣ Photophobia – most commonly associated with uveitis, keratitis or AACG.
‣ Itching in allergic conjunctivitis.
‣ Consider asking about systemic symptoms – fever, lymphadenopathy, N&V, joint pain etc.
Ocular History
Personal ocular history:
‣ Previous episodes of episcleritis or uveitis.
‣ Known glaucoma – may have recently changed their eye drops or had surgery.
‣ Cataract – large hypermature cataracts can block the angle leading to AACG.
Operations:
‣ Any recent ocular surgery or intravitreal injections – any acutely painful red eye having had recent intra-ocular surgery (within 1/52) should raise alarm bells for endophthalmitis.
‣ It is also relatively common for patient to suffer uveitis post-operatively.
Contact lens wear:
‣ Type of lens – soft or rigid, daily disposable or reusable. Soft reusable lenses carry higher risk of infections.
‣ If using reusable or rigid lenses do they clean them as instructed?
‣ How long do they wear them – the more hours per day they are worn, the more likely they are to suffer with dry eye.
‣ Do they shower or swim in contact lenses – high risk behaviour for acanthamoeba keratitis.
‣ Do they sleep in their contact lenses – high risk behaviour for corneal infection.
‣ Any previous contact lens complications/infections.
Any known ocular history that runs in the family such as uveitis and glaucoma.
Background
Past Medical History
‣ Recent viral illness – think viral conjunctivitis.
‣ Rheumatological conditions can linked to uveitis.
‣ Autoimmune conditions such as IBD, T1DM and ank spond can be associated with uveitis and scleritis.
‣ Immunocompromised – more susceptible to infections.
‣ Diabetes – immunosuppressed and complications can lead to angle blockage.
‣ STI – can link to chlamydial conjunctivitis and neonatal conjunctivitis in a newborn.
Drug History
‣ New drops – preservatives?
‣ Anticoagulants – link to subconjunctival haemorrhage.
‣ Digoxin toxicity can cause a yellow tinge to vision.
‣ Many systemic drugs can cause a wide range of ocular effects. There are too many to list here, but the key question is – has anything new been started recently?
Allergies/Atopy
‣ Does the patient have known allergy to preservatives in drops?
‣ Do they suffer with seasonal allergies?
‣ Known asthma or eczema?
Occupation
‣ Trades-people are more likely to get FB injuries.
‣ Do they wear safety glasses/goggles for work?
‣ Desk workers are often on computers all day leading to dry eye.
‣ Air conditioning
‣ Dusty environment
‣ Exposure to chemicals, particles/FBs.
Other
• Travel.
• Any unwell contacts.
• Activities/Sports – weight lifting can trigger subconjunctival haemorrhage.
• Driving – always ask about driving in an ophthalmic history and advise not to if vision is at insufficient level to be legal/safe.
Author – Dr Prajay Bhogaita
Editor – Dr James Mackintosh
Last updated 18/12/23
