What causes floaters in the eye?

Causes of Eye Floaters

Floaters are most commonly caused by posterior vitreous detachment (PVD), an age-related process where the vitreous gel separates from the retina, typically occurring between ages 45-65. 1

Primary Pathophysiologic Mechanisms

Age-Related Vitreous Changes

• Vitreous syneresis is the fundamental age-related process where the vitreous gel liquefies, causing collagen fibers to condense and clump together, casting shadows on the retina that appear as floaters 1
• Posterior vitreous detachment occurs when the posterior vitreous cortex separates from the internal limiting membrane of the retina, creating visible opacities that patients perceive as floaters 2
• PVD occurs earlier in men and can develop prematurely in patients with trauma or myopia 2

Vitreoretinal Traction Sites

• During the detachment process, vitreous traction occurs at specific sites of firm vitreoretinal adhesion, particularly at the macula, optic nerve head, and vitreous base 1
• This traction can create additional opacities and potentially lead to more serious complications 1

Secondary Causes of Floaters

Hemorrhagic Causes

• Vitreous hemorrhage from diabetic retinopathy can cause floaters, often appearing as a sudden shower of new floaters or "smoke" in the vision 1
• Retinal tears with associated bleeding contribute to floater formation 3

Inflammatory Causes

• Inflammatory eye diseases cause cellular debris to accumulate in the vitreous cavity, producing floaters 1

Myopic Vitreopathy

• Myopic eyes develop vitreous changes and floaters independent of age-related PVD 4
• Myopic vitreopathy accounts for 15.4% of symptomatic floaters requiring intervention, and can coexist with PVD in another 28.7% of cases 4

Other Causes

• Asteroid hyalosis causes floaters in approximately 6.7% of symptomatic cases 4

Critical Warning Signs Requiring Urgent Evaluation

Between 8-22% of patients with acute PVD symptoms have a retinal tear at initial examination, making urgent ophthalmologic evaluation essential for new-onset floaters. 3

Red Flags Requiring Same-Day Ophthalmology Referral

• New-onset floaters accompanied by flashes of light (photopsias) indicate vitreoretinal traction 3
• Sudden shower of new floaters suggests possible vitreous hemorrhage 3
• Floaters with peripheral visual field loss may indicate retinal detachment 3
• Floaters with sudden decrease in visual acuity requires immediate evaluation 3

Risk Stratification

• Patients with vitreous pigment cells, vitreous/retinal hemorrhage, or visible vitreoretinal traction at initial examination have the highest risk of retinal breaks 3
• Even patients with no retinal breaks initially still have a 2-5% chance of developing breaks in the following 6 weeks 3
• Approximately 80% of patients who later develop breaks had either pigmented cells, hemorrhage, or new symptoms prompting return 3

Common Pitfalls to Avoid

• Never assume all floaters are benign without proper dilated examination with scleral depression by an ophthalmologist skilled in binocular indirect ophthalmoscopy 3
• Failing to recognize that retinal breaks can develop weeks after initial symptoms leads to preventable vision loss 3
• Patients who undergo refractive surgery for myopia remain at risk for retinal detachment despite correction of their refractive error 2
• Underestimating the impact on quality of life is common, as studies demonstrate significant reduction in contrast sensitivity function (91.3% degradation compared to controls) in symptomatic patients 4