The acute red eye is a common presentation in the primary care setting. Most cases are benign in nature, with conjunctivitis being the most common aetiology. There are; however, several serious pathologies that clinicians need to be aware of that require urgent recognition and management.
These serious and potentially sight-threatening causes of red eye include:
- Acute glaucoma
- Corneal ulcer, contact lens-related red eye and corneal foreign body
- Anterior uveitis
- Scleritis
- Trauma, such as penetrating eye injury or high-velocity foreign body
- Chemical injuries
- Neonatal conjunctivitis.
Assessment of the acute red eye
The assessment of a person with red eye involves taking a detailed history and performing a thorough examination.
Important points in the history include:
- What is the onset and duration of symptoms?
- How painful is the eye? (Higher pain levels are more likely with microbial keratitis or mechanical abrasion)
- Are the symptoms unilateral or bilateral?
- What associated symptoms are present? (visual changes, pain, foreign body sensation, discharge or photophobia),
- Does the patient use of contact lenses? (Any presentation of red eye in a contact lens user requires urgent referral for possible microbial keratitis
- Is there any history of trauma or chemical exposure?
- Does the patient have a history of previous episodes?
- It is important to inquire about relevant past medical history and medication. (e.g. cold sores and atopy are risk factors for herpes simplex keratopathy)
Examination of the patient should include the following:
- Administration of topical local anaesthetic if pain scores are high
- Inspection of the eye (check for discharge and obvious facial trauma)
- Check for trichiasis, entropion and ectropion (entropion can cause corneal abrasion and ectropion can cause dry eye and exposure keratopathy)
- Assessment of visual acuity
- Examine the conjunctiva, including the tarsal surface (if a foreign body is a possibility, the upper lid should be everted to check for a sub-tarsal foreign body)
- Fluorescein examination (look for yellow-green uptake using blue light on ophthalmoscopy)
- Assess pupil reactions (check if the person is photophobic, observe pupil size and shape and check direct and consensual pupillary reflexes)
- Check the person’s blood pressure, if subconjunctival haemorrhage is suspected.
Document the history and findings of eye examinations (including negative findings). This is particularly important when the management of a unilateral red eye is going to take place in primary care.
Conditions requiring urgent same day referral
The following table summarises the typical clinical features of common urgent conditions that require urgent same day referral:
| Condition | Typical history features | Typical examination features |
|---|---|---|
| Acute glaucoma | Unilateral eye pain Headache Blurring of vision Lights surrounded by haloes Nausea and vomiting | Reduced visual acuity Tender and hard eye Ciliary injection Fixed, mid-dilated pupil |
| Corneal ulcer (and contact lens-related red eye) | Photophobia Blurred vision Pain | Severe conjunctival injection Visible discharge Eyelid swelling Visible ulceration on fluorescein staining of the cornea |
| Corneal foreign body | Prior history of wind blowing into eye Prior history of use of hammering or grinding tools Sensation of foreign body Pain Photophobia | Visible corneal foreign body on examination Visual acuity and pupil reflexes usually normal |
| Anterior uveitis | Pain (worse when contracting ciliary muscles) Photophobia Watering of eye Past history of inflammatory disorders (e.g. ankylosing spondylitis) | Ciliary injection Constricted or distorted pupil Visual acuity may be normal or reduced |
| Scleritis | Severe pain Past history of connective tissue disorders (e.g. rheumatoid arthritis or SLE) | Reduced visual acuity Abnormal pupil reactions Scleritis can lead to perforation of the globe |
| Neonatal conjunctivitis | Diagnosed in any infant presenting with conjunctivitis in first 28 days of life | Corneal ulceration may occur in gonorrhoeal conjunctivitis Neonatal chlamydial infection can be associated with a systemic infection, such as pneumonia |
Further reading:
NICE Clinical Knowledge Summary on the Red Eye
Thank you to the joint editorial team of www.mrcgpexamprep.co.uk for this article.
