A subconjunctival haemorrhage (SCH) can appear alarming to patients: the sudden, bright red bleeding on the white of the eye can often raise fears of a serious problem. However, for doctors, it is crucial to distinguish between a harmless cause and an underlying condition which needs further investigation.
This article aims to provide medical students and resident doctors with a structured approach to help them recognise, evaluate, and manage subconjunctival haemorrhages.
What is a Subconjunctival Haemorrhage?
https://my.clevelandclinic.org/health/diseases/17713-subconjunctival-hemorrhage – An image portraying a subconjunctival haemorrhage. Last accessed 02/06/25
A subconjunctival haemorrhage occurs when a small blood vessel ruptures beneath the conjunctiva, which is the transparent membrane covering the sclera (1). The blood becomes trapped between the conjunctiva and the sclera, which produces a well-demarcated red patch.
In most cases, it is benign and self-limiting. However, occasionally, it may indicate a more serious underlying pathology such as trauma, coagulopathy, or systemic hypertension (2).
Clinical Features
| Feature | Subconjunctival Haemorrhage |
| Onset | Sudden |
| Appearance | Bright red, sharply defined patch on sclera |
| Pain | Absent or mild discomfort |
| Visual acuity | Normal in isolated SCH (may be abnormal in traumatic cases) |
| Discharge | None |
| Location | Usually unilateral unless trauma |
| Progression | Blood may spread initially, then resolve |
| Duration | Typically clears within 1-2 weeks |
Common Causes
Below are the common causes of a SCH (3).
- Idiopathic – up to 40% of cases.
- Minor trauma (e.g. rubbing eyes or the Valsalva manoeuvre)
- Hypertension
- Bleeding disorders or anticoagulant use
- Sudden increases in venous pressure (e.g., coughing, vomiting)
- Iatrogenic (e.g., post-surgery (2), contact lens complications)
When to Reassure
In most cases, SCH is idiopathic or caused by minor events and so does not require treatment. Patients can be reassured that:
- It is like a bruise and will resolve spontaneously
- There is no threat to vision
- No specific drops or medications are needed
Artificial tears may be offered to reduce discomfort.
When to Worry – Red Flags
Below are red flag symptoms, and possible underlying concerns, in patients with SCH.
| Red Flag | Possible Underlying Concern |
| Recurrent SCH | Bleeding diathesis, hypertension |
| Associated trauma | Globe rupture, orbital fracture |
| Vision loss | Posterior segment involvement |
| Painful red eye | Scleritis, uveitis, or secondary pathology |
| Bilateral haemorrhages | Coagulopathy or systemic vascular cause |
| Patient on anticoagulants | Over-anticoagulation, bleeding risk |
| Concomitant petechiae/ecchymoses | Platelet or clotting disorder |
| Bilateral SCH in children | Non-accidental injury |
What You Can Do as a Resident Doctor
- History: Ask about any trauma, medications patients are on, bleeding tendencies, or systemic illnesses.
- Examination:
- Check visual acuity
- Inspect for signs of trauma or globe injury
- Measure their blood pressure
- Investigations (primarily done if there are red flag symptoms): Â
- INR/PTT in patients on anticoagulants – if above therapeutic range/high bleeding risk, liaise with haematology.
- Full blood count to assess platelet count if concerned
- BP measurement
- Referral:
- Urgent referral if there is trauma with suspected globe rupture
- Haematology if coagulopathy suspected
- Ophthalmology for atypical or recurrent cases (4)
Take-Home Points
- Subconjunctival haemorrhages are common and usually benign.
- Rule out trauma, bleeding disorders, and elevated blood pressure.
- Reassure the patient and avoid unnecessary interventions.
- Refer urgently if there are red flags like pain, vision loss, or trauma.
References
- Doshi R, Noohani T. Subconjunctival Hemorrhage. [Updated 2023 Feb 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551666/
- Liu DT, Choi PC, Lam DS. Subconjunctival hemorrhage: a prospective study of 59 cases. Hong Kong Med J.2001;7(5):428–430.
- Tarlan B, Kiratli H. Subconjunctival hemorrhage: risk factors and potential indicators. Clin Ophthalmol. 2013;7:1163-70. doi: 10.2147/OPTH.S35062. Epub 2013 Jun 12. PMID: 23843690; PMCID: PMC3702240.
- The Royal College of Ophthalmologists. Emergency Eye Care Guidelines. Updated 2021. https://rcophth.ac.uk
Written by Dr Michael Milad (FY1) & reviewed by Mr Matthew George (Post-CCT Ophthalmology Fellow)
