Modifiable Risk Factors for Non-traumatic Subconjunctival Hemorrhage

Subconjunctival hemorrhage (SCH) is characterized by the rupture of a small conjunctival or episcleral blood vessel, leading to localized extravasation of blood beneath the conjunctiva.1, 2 Non-traumatic cases occur without external mechanical injury.1, 2 Clinically, it manifests as a sharply demarcated bright or dark red patch on the sclera, often prompting concern due to its striking appearance.1 Despite its alarming presentation, SCH is generally a benign condition that neither causes pain nor affects visual acuity, although some patients may report mild ocular discomfort or a foreign-body sensation.1 SCH typically resolves spontaneously within 1 to 2 weeks, analogous to the resolution of a cutaneous bruise, as the extravasated blood is gradually resorbed.3 While most cases are isolated and self-limiting, recurrent SCH or episodes accompanied by other ocular or systemic symptoms warrant further evaluation to exclude underlying systemic disorders.4, 5 Identifying risk factors for SCH is clinically important, as it may facilitate the early diagnosis and management of systemic conditions, thereby reducing the likelihood of recurrence. The most common precipitating factor is minor ocular trauma, such as vigorous eye rubbing.6 Other recognized triggers include acute increases in venous pressure associated with coughing, sneezing, or Valsalva maneuvers, as well as the use of anticoagulant or antiplatelet agents, including warfarin and aspirin.1, 6 Although vascular disorders such as hypertension and diabetes mellitus have been suggested as potential systemic risk factors, the literature addressing these associations remains limited.1, 7, 8 Thus, this study aimed to identify potential risk factors associated with SCH. Initially, a retrospective analysis was conducted to explore candidate risk factors, followed by a prospective study to validate the findings.