Differential Diagnosis of Flashing Lights in the Eyes

Life-Threatening and Vision-Threatening Causes

Between 8-22% of patients with acute posterior vitreous detachment (PVD) symptoms have a retinal tear at initial presentation, making this the most critical diagnosis to exclude 1, 2
Photopsias occur due to vitreous traction on the retina as the vitreous separates from its attachments 1
Red flags for vision-threatening causes include new-onset flashes with floaters, sudden shower of floaters, peripheral visual field loss, or decreased visual acuity 2, 3
Even patients with no retinal breaks initially have a 2-5% chance of developing breaks within 6 weeks 2
Approximately 80% of patients who later develop breaks had pigmented cells, hemorrhage, or new symptoms at initial evaluation 2

Trauma-induced PVD can precipitate PVD at younger ages than typical age-related PVD, with symptoms appearing immediately or developing within 6 weeks following trauma 1
White dot syndromes, such as acute posterior multifocal placoid pigment epitheliopathy, present with rapid onset vision loss and photopsias 4
Posterior scleritis can cause flashes along with deep pain and painful eye movements 4
Vogt-Koyanagi-Harada disease presents bilaterally in 95% of cases with multiple systemic findings 4

Any patient with flashing lights plus new floaters, peripheral visual field loss, decreased visual acuity, or history of recent ocular trauma requires same-day ophthalmologic evaluation 2, 1
A thorough peripheral fundus examination with scleral depression by an ophthalmologist skilled in binocular indirect ophthalmoscopy is required 2
B-scan ultrasonography may be necessary if media opacity prevents adequate visualization 1, 2

Assuming all photopsias are benign without proper retinal examination can lead to missed retinal tears and subsequent detachment 2
Failing to recognize that retinal breaks can develop weeks after initial symptoms, even when initial examination is normal 2
Overlooking the need for 6-week follow-up in patients with vitreous pigment, hemorrhage, or visible vitreoretinal traction 1, 2

Patients with acute photopsias but no retinal breaks on initial examination should return within 6 weeks, as this is the critical period when retinal breaks may develop 1, 2