Description

• Subconjunctival hemorrhage (SCH) is bleeding from small blood vessels underneath the conjunctiva, the thin clear skin covering the sclera (white outer layer) of the eye.
• SCH is diagnosed clinically:
  • Well-demarcated areas of extravasated blood can be seen just under the surface of the conjunctiva of the eye.
  • Lesions can be flat, elevated, or bullous.
• Typically, SCH self-resolves in a few days to weeks depending on the severity.

Epidemiology

Common; 3% rate of diagnosis in ophthalmology clinics (1)

Incidence
Incidence increases

• With increasing age
• In contact lenses wearers (5% of cases) (2)
• With systemic diseases such as diabetes, hypertension (HTN), and coagulation disorders
• With trauma
• During summer months, possibly due to trauma (1)

Etiology and Pathophysiology

• SCH results from damage to conjunctival and episcleral vessels from direct or indirect injury.
• Antithrombogenic and anticoagulated states (blood dyscrasias, thrombocytopenia, anemia, anti-platelet use, anticoagulant use) increase the risk and severity of SCH.
• Causes include the following:
  • Idiopathic
  • Direct trauma from
    • Blunt or penetrating injury to the eye
      • If there is a large SCH from a trauma, the patient may have underlying globe rupture and should be evaluated for this.
    • Contact lenses placement or removal; improper contact lenses wear
    • Rubbing eyes
      • Commonly when sleeping, which leads to patient waking up with eye redness
      • In patient on anticoagulation, even mild eye rubbing can induce SCH.
    • Foreign body in eye
    • Ocular surgery, injection, or other procedure
    • Related to ocular surface infection (i.e., viral conjunctivitis) or ocular surface lesion
  • Valsalva maneuvers causing sudden severe venous congestion such as coughing, sneezing, vomiting, straining, severe asthma or COPD exacerbation, weight lifting, or childbirth/labor
  • Damaged vessels from atherosclerotic disease or diabetes (which is a cause of recurrent SCH without trauma)
• In patients aged >60 years, HTN is the most common etiology.
• In patients aged <40 years, trauma, Valsalva maneuver, and contact lenses use are the most common etiologies.
• In patients aged >40 years, conjunctivochalasis (redundant conjunctival folds) and presence of pinguecula are strongly associated (2).

Risk Factors

• Trauma
• Age
• Contact lenses wearer
• Systemic diseases (HTN, diabetes)
• Bleeding disorders (1)
• Recent ocular procedure (cataract, laser-assisted in situ keratomileusis [LASIK])

General Prevention

• Avoid rubbing the eyes.
• Proper cleaning and maintenance of contact lenses
• Protective eyewear during sports and hobbies
• Optimizing control of systemic diseases such as HTN, diabetes, atherosclerotic disease, and thrombocytopenia.
• Control of PT/INR in patients on warfarin therapy (3)