What causes black floaters in the eyes without ocular trauma?

From the Guidelines

Black floaters in the eyes without trauma are most likely caused by posterior vitreous detachment (PVD), which can lead to retinal breaks and detachment, and therefore, it is crucial to seek immediate medical attention if symptoms persist or worsen. According to a study published in Ophthalmology in 2020 1, PVD typically occurs between the ages of 45 and 65, and its symptoms include light flashes and floaters. The floaters may be due to condensations of vitreous collagen or the epipapillary glial tissue that is torn from the optic nerve head.

Some key points to consider include:

• Between 8% and 22% of patients with acute PVD symptoms have a retinal tear at the time of the initial examination 1
• Patients with an acute PVD who have no reported retinal breaks on presentation have a 2% to 5% chance of experiencing a detected break in the weeks that follow 1
• A spontaneous vitreous hemorrhage can be the presenting sign of PVD or may occur during the evolution of the PVD, and approximately 88% of the breaks occurred in the superior quadrants 1

It is essential to note that while most floaters are harmless, a sudden increase in floaters, especially when accompanied by flashes of light or vision loss, could indicate a retinal tear or detachment, which requires immediate medical attention. Other causes of black floaters include eye inflammation, bleeding in the eye from conditions like diabetic retinopathy, or complications from eye surgeries. If you're experiencing new or worsening floaters, it's best to see an eye doctor for a comprehensive examination to rule out serious conditions.

From the Research

Black Floaters in the Eyes with No Trauma

• Black floaters in the eyes can be caused by various factors, including posterior vitreous detachment (PVD) 2, 3, 4.
• PVD is a condition where the vitreous gel in the eye separates from the retina, which can cause floaters and flashes 2, 3.
• Studies have shown that the presence of floaters, especially more than 10, is associated with a higher risk of developing retinal tears 3.
• The onset of flashes and floaters, as well as the presence of retinal and/or vitreous haemorrhage, are risk factors for the development of retinal tears 3.
• A systematic review found that the presence of isolated flashes was associated with the development of retinal tears in 5.3% of symptomatic eyes, while floaters alone had a stronger association with retinal tears (16.5% of eyes) 3.
• Another study found that symptom-based predictive factors for retinal tears and detachments included the presence of subjective visual reduction or subjective field loss, and the absence of either floaters or flashes 4.

Risk Factors for Retinal Tears and Detachments

• The presence of more than 10 floaters or a cloud in the vision is associated with a high risk of developing retinal tears 3.
• Patients with retinal tears were more likely to report floaters and less likely to report subjective field loss compared to those with retinal detachments 4.
• The number, duration, and timing of flashes and floaters may be less relevant in the triage of patients with PVD symptoms 4.
• A prospective cohort study found that significant differences in demographic and examination-based factors were observed between patients with PVD, vitreous syneresis, and retinal tears/retinal detachments 4.