Acute-Onset Floaters and Flashes

CONTEXT: Acute onset of monocular floaters and/or flashes represents a common presentation to primary care physicians, and the most likely diagnosis is posterior vitreous detachment (PVD). A significant proportion of patients with acute PVD develop an associated retinal tear that can lead to retinal detachment and permanent vision loss if left untreated. OBJECTIVE: To quantify the association between relevant clinical variables and risk of retinal tear in patients presenting with acute-onset floaters and/or flashes and PVD. DATA SOURCES: Structured MEDLINE (January 1950-September 2009) and EMBASE (January 1980-September 2009) searches and a hand search of references and citations of retrieved articles yielded 17 relevant studies. STUDY SELECTION: Studies of high-level methods that related elements of the history or physical examination in patients presenting with floaters and/or flashes and PVD to the likelihood of retinal tear. RESULTS: For patients with acute onset of floaters and/or flashes who are self-referred or referred to an ophthalmologist, the prevalence of retinal tear is 14% (95% confidence interval CI, 12%-16%). Subjective visual reduction is the most important symptom associated with retinal tear (likelihood ratio LR, 5.0; 95% CI, 3.1-8.1). Vitreous hemorrhage on slitlamp biomicroscopy is the best-studied finding with the narrowest positive LR for retinal tear (summary LR, 10; 95% CI, 5.1-20). Absence of vitreous pigment during this examination is the best-studied finding with the narrowest negative LR (summary LR, 0.23; 95% CI, 0.12-0.43). Patients initially diagnosed as having uncomplicated PVD have a 3.4% chance of a retinal tear within 6 weeks. The risk increases with new onset of at least 10 floaters (summary LR, 8.1-36) or subjective visual reduction (summary LR, 2.3-17) during this period. CONCLUSIONS: Primary care physicians should evaluate patients with acute-onset floaters and/or flashes due to suspected PVD, or patients with known PVD and a change in symptoms, for high-risk features of retinal tear and detachment. Physicians should always assess these patients' visual acuity. Patients at increased risk should be triaged for urgent ophthalmologic assessment.