Flashing Lights After Pan Retinal Photocoagulation
Flashing lights (photopsias) are not a documented complication of pan retinal photocoagulation (PRP) itself, but rather represent symptoms of posterior vitreous detachment or retinal traction that may occur independently or be precipitated by the procedure.
Understanding the Distinction
The available evidence does not establish flashing lights as a direct side effect of PRP treatment. The guidelines and research focus on:
Visual outcomes and complications documented after PRP include vitreous hemorrhage (37% develop new hemorrhage within first year), traction retinal detachment (6% newly developed), impaired dark adaptation (35.6% develop abnormal dark adaptation), and decreased retinal blood flow 1, 2, 3, 4
Flashing lights are characteristic symptoms of posterior vitreous detachment (PVD), not laser photocoagulation 5, 6
When Flashing Lights Occur in This Context
If a patient experiences flashing lights after PRP, consider these mechanisms:
Surgical trauma can precipitate PVD, including procedures like cataract surgery and intraocular injections, which suggests laser procedures could theoretically trigger vitreoretinal traction 6
Photopsias result from vitreous traction on the retina as the vitreous separates from the posterior retina, not from laser burns themselves 5, 6
8-22% of patients with acute PVD symptoms have a retinal tear at initial examination, and 2-5% develop breaks in the following weeks 5, 6, 7, 8
Critical Clinical Response
Any patient reporting new flashing lights after PRP requires urgent ophthalmologic evaluation within 6 weeks to rule out retinal breaks or detachment 6, 7:
- Perform comprehensive dilated fundus examination with scleral depression 7
- Evaluate vitreous for pigment, hemorrhage, or syneresis 6, 7
- Use B-scan ultrasonography if media opacity prevents visualization 6, 7
- Two-thirds of patients with vitreous hemorrhage have at least one retinal break 8
Common Pitfall to Avoid
Do not dismiss new photopsias as a "normal" post-laser phenomenon - this symptom warrants the same urgent evaluation as any new-onset flashing lights, as retinal breaks can develop weeks after the initial event and are not a documented direct effect of the laser treatment itself 6, 7, 8.