Causes of Scleral Hemorrhage (Subconjunctival Hemorrhage)
Scleral hemorrhage, more accurately termed subconjunctival hemorrhage, most commonly results from spontaneous rupture of small conjunctival vessels, though trauma, bleeding disorders, and vascular disease represent important secondary causes that require systematic evaluation.
Primary Mechanisms
Spontaneous Vessel Rupture
- Spontaneous bleeding from fragile conjunctival vessels is the most common cause in adults, occurring without identifiable precipitating factors 1
- Valsalva maneuvers (coughing, sneezing, straining, vomiting) can precipitate vessel rupture by causing sudden venous pressure elevation
- Minor trauma including eye rubbing frequently causes subconjunctival hemorrhage
Trauma-Related Causes
- Blunt ocular trauma can cause subconjunctival hemorrhage ranging from isolated vessel rupture to severe scleral rupture with extensive hemorrhage 2, 3
- In cases of blunt trauma with subconjunctival hemorrhage, scleral rupture must be excluded, particularly when accompanied by hyphema (present in 67-80% of scleral ruptures), subconjunctival hemorrhage, eyelid swelling, or shallow anterior chamber 2, 3
- Scleral rupture from blunt trauma most commonly occurs in the superonasal quadrant (41%) and posterior pole regions 2, 3
- Old surgical scars can dehisce after minor blunt trauma, causing filtering bleb formation and hemorrhage 4
Systemic and Hematologic Causes
- Hypertension is a significant risk factor for spontaneous subconjunctival hemorrhage, particularly in elderly patients 5
- Coagulation disorders including factor deficiencies, thrombocytopenia, and anticoagulant use (warfarin, heparin, antiplatelet agents) predispose to bleeding 6
- Vitamin K deficiency can cause hemorrhage, though this is more relevant in infants than adults 6
Vascular and Inflammatory Causes
- Conjunctival vessel fragility increases with age, making spontaneous hemorrhage more common in elderly patients 1
- Vasculitis from autoimmune conditions (systemic lupus erythematosus, rheumatoid arthritis) can affect conjunctival vessels, though severe necrotizing scleritis is rare 7, 8
- Retinal vein occlusions are associated with systemic vascular disease but do not directly cause subconjunctival hemorrhage 5
Critical Diagnostic Approach
Immediate Assessment Required
- Rule out globe rupture in any trauma case by checking for:
B-scan Ultrasonography Indications
- Perform urgent ultrasound when fundus view is obscured to identify:
- Ill-defined scleral margins (90% sensitive for rupture)
- Vitreous hemorrhage (80% in ruptures)
- Retinal or choroidal detachment 3
Laboratory Evaluation
- Check coagulation studies (PT, aPTT, platelet count) if:
- Recurrent episodes occur
- Bilateral hemorrhages present
- Patient takes anticoagulants
- Hemorrhage is unusually extensive 6
Common Pitfalls to Avoid
- Do not miss occult globe rupture: Any subconjunctival hemorrhage with 360-degree limbal involvement ("chemosis sign"), severe pain, or decreased vision requires immediate ophthalmologic evaluation 2
- Do not overlook medication history: Specifically ask about anticoagulants, antiplatelets, and supplements (fish oil, vitamin E) that affect coagulation
- Do not dismiss recurrent hemorrhages: Multiple episodes warrant systemic evaluation for hypertension, bleeding disorders, or vascular fragility 5, 1