“Black floaters” are a symptom, not a diagnosis. They can arise from ordinary collagen condensations, blood, inflammatory cells, infectious vitritis, pigment, tumor cells, protein deposits, or other vitreous material. The National Eye Institute specifically lists aging, vitreous detachment, hemorrhage, uveitis/infection, retinal tears and retinal detachment among important causes.
1. Age-Related Vitreous Syneresis / Collagen Condensation — Very Common.
With aging, vitreous liquefaction and aggregation of collagen fibrils create mobile opacities whose shadows are perceived as dots, threads, hairs or cobwebs.
Full reference: Sebag J. Posterior vitreous detachment. Ophthalmology. 2018;125(11):1795-1796. doi:10.1016/j.ophtha.2018.05.018.
2. Posterior Vitreous Detachment (PVD) — Very Common.
Separation of the posterior vitreous cortex produces new floaters, often from collagen condensations or a Weiss ring. Acute PVD is especially important because it can produce retinal tears.
Full reference: American Academy of Ophthalmology Retina/Vitreous Panel. Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration Preferred Practice Pattern®. Ophthalmology. 2025.
3. Retinal Tear Associated With PVD — Urgent.
Vitreoretinal traction can tear the retina and rupture a retinal vessel, releasing blood or pigment into the vitreous. This may produce a sudden shower of dark spots.
Full reference: American Academy of Ophthalmology Retina/Vitreous Panel. Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration Preferred Practice Pattern®. Ophthalmology. 2025.
4. Rhegmatogenous Retinal Detachment — Emergency.
A retinal break can progress to retinal detachment. Floaters and flashes may precede the classic expanding curtain, veil or peripheral visual-field defect.
Full reference: American Academy of Ophthalmology Retina/Vitreous Panel. Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration Preferred Practice Pattern®. Ophthalmology. 2025.
5. Vitreous Hemorrhage — Major Cause of Black Floaters.
Blood in the vitreous can appear as black/red dots, strings, cobwebs, clouds or diffuse haze. Importantly, vitreous hemorrhage can result from many underlying diseases.
Full reference: Shaikh N, et al. Vitreous hemorrhage—Causes, diagnosis, and management. Indian J Ophthalmol. 2023;71. PMID: 36588205.
6. Proliferative Diabetic Retinopathy.
Fragile retinal neovascular vessels can bleed into the vitreous, sometimes causing a sudden onset of dark floaters and vision loss. PDR is one of the major causes of spontaneous vitreous hemorrhage.
Full reference: Spraul CW, Grossniklaus HE. Vitreous hemorrhage. Surv Ophthalmol. 1997;42(1):3-39. doi:10.1016/S0039-6257(97)84041-6. PMID: 9265701.
7. Retinal Vein Occlusion.
Central or branch retinal vein occlusion can cause retinal ischemia, neovascularization, and subsequent vitreous hemorrhage.
Full reference: Spraul CW, Grossniklaus HE. Vitreous hemorrhage. Surv Ophthalmol. 1997;42(1):3-39. doi:10.1016/S0039-6257(97)84041-6.
8. Retinal Arterial Macroaneurysm.
Rupture of a retinal arterial macroaneurysm can generate preretinal and vitreous blood perceived as dark spots or haze. It is an occasionally overlooked source of vitreous hemorrhage.
Full reference: Lindgren G, Lindblom B. Causes of vitreous hemorrhage. Curr Opin Ophthalmol. 1996;7(3):13-19. doi:10.1097/00055735-199606000-00003. PMID: 10163454.
9. Retinal Vasculitis.
Inflamed retinal vessels can leak or occlude, producing ischemia, neovascularization and hemorrhage. The accompanying inflammatory cells can independently produce floaters.
Full reference: Shaikh N, et al. Vitreous hemorrhage—Causes, diagnosis, and management. Indian J Ophthalmol. 2023. PMID: 36588205.
10. Proliferative Sickle-Cell Retinopathy.
Peripheral retinal ischemia can produce fragile neovascularization, which can rupture and bleed into the vitreous.
Full reference: Shaikh N, et al. Vitreous hemorrhage—Causes, diagnosis, and management. Indian J Ophthalmol. 2023. PMID: 36588205.
11. Neovascular Age-Related Macular Degeneration (AMD).
Choroidal neovascularization can hemorrhage and, less commonly, blood can extend into the vitreous cavity, creating dark floaters/haze.
Full reference: Shaikh N, et al. Vitreous hemorrhage—Causes, diagnosis, and management. Indian J Ophthalmol. 2023. PMID: 36588205.
12. Pathologic/High Myopia.
High myopia predisposes to earlier PVD and retinal tears; pathologic myopia may also develop choroidal neovascularization and hemorrhage. Thus several mechanisms can generate new floaters.
Full reference: American Academy of Ophthalmology Retina/Vitreous Panel. Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration Preferred Practice Pattern®. Ophthalmology. 2025.
13. Blunt Ocular Trauma.
Trauma can produce PVD, retinal breaks, retinal detachment or direct vitreous hemorrhage.
Full reference: Shaikh N, et al. Vitreous hemorrhage—Causes, diagnosis, and management. Indian J Ophthalmol. 2023. PMID: 36588205.
14. Penetrating/Open-Globe Ocular Trauma.
Penetrating injury can introduce blood, inflammatory material and/or foreign material into the vitreous and can damage the retina.
Full reference: Shaikh N, et al. Vitreous hemorrhage—Causes, diagnosis, and management. Indian J Ophthalmol. 2023. PMID: 36588205.
15. Valsalva Retinopathy.
Sudden elevation of intrathoracic/intra-abdominal pressure can rupture superficial retinal capillaries, causing preretinal hemorrhage; blood may occasionally enter the vitreous.
Full reference: Spraul CW, Grossniklaus HE. Vitreous hemorrhage. Surv Ophthalmol. 1997;42(1):3-39. doi:10.1016/S0039-6257(97)84041-6.
16. Terson Syndrome.
Subarachnoid or other acute intracranial hemorrhage with markedly increased intracranial pressure can be accompanied by retinal, preretinal, and vitreous hemorrhage.
Full reference: Shaikh N, et al. Vitreous hemorrhage—Causes, diagnosis, and management. Indian J Ophthalmol. 2023. PMID: 36588205.
17. Blood Dyscrasias/Coagulation Disorders.
Leukemia, severe thrombocytopenia, and other hematologic/coagulation abnormalities can facilitate retinal or vitreous hemorrhage. Anticoagulants should not automatically be assumed to be the primary cause; underlying ocular pathology still needs investigation.
Full reference: Spraul CW, Grossniklaus HE. Vitreous hemorrhage. Surv Ophthalmol. 1997;42(1):3-39. doi:10.1016/S0039-6257(97)84041-6.
Inflammatory and Infectious Causes
18. Intermediate Uveitis / Vitritis.
Inflammatory leukocytes and proteinaceous debris suspended in the vitreous can be perceived as numerous dots, strands or hazy floaters. Intermediate uveitis is specifically included among causes associated with vitreous hemorrhage as well.
Full reference: Shaikh N, et al. Vitreous hemorrhage—Causes, diagnosis, and management. Indian J Ophthalmol. 2023. PMID: 36588205.
19. Posterior Uveitis / Panuveitis.
Posterior-segment inflammation can produce vitritis, inflammatory cells and debris that patients experience as dark floaters.
Full reference: National Eye Institute. Floaters. National Institutes of Health; updated 2024.
20. Ocular Toxoplasmosis — Important Infectious Cause.
Toxoplasma gondii produces necrotizing retinochoroiditis that is commonly accompanied by vitritis. Sudden floaters and blurred vision are well-described presentations.
Full reference: Tabbara KF. Ocular toxoplasmosis. Int Ophthalmol. 1990;14(5-6):349-351. doi:10.1007/BF00163555. PMID: 2249911.
21. Cytomegalovirus (CMV) Retinitis.
Particularly in immunocompromised patients, CMV retinitis can present with multiple floaters, blurred/decreased vision and peripheral visual-field loss.
Full reference: CMV retinitis: diagnosis and status of systemic therapy. PubMed PMID record. PMID: 9058611.
22. Herpetic Acute Retinal Necrosis (HSV/VZV).
HSV or VZV can cause necrotizing retinitis with vitritis and retinal vasculitis. Vitreous inflammatory material can produce floaters, while retinal necrosis can subsequently predispose to retinal detachment.
Supporting reference: The broader clinical differential for vitreous opacities includes infectious vitreous inflammation/retinochoroiditis; severe vitritis can accompany infectious posterior-segment disease.
23. Endophthalmitis.
Bacterial or fungal infection inside the eye can create intense inflammatory cells and debris in the vitreous. Floaters may accompany reduced vision, pain, redness or other inflammatory findings, although presentations vary.
Full reference: National Eye Institute. Floaters. National Institutes of Health; 2024. Eye infection is listed as a serious cause of floaters.
24. Ocular Syphilis / Syphilitic Posterior Uveitis.
Treponema pallidum can cause posterior uveitis, retinitis, retinal vasculitis, and vitritis. When vitreous inflammatory cells are substantial, patients may report floaters. This is an important infectious masquerader in unexplained posterior uveitis.
Supporting reference: Infectious vitreous inflammation and retinochoroiditis are established differential diagnoses for vitreous opacities.
25. Sarcoid-Associated Uveitis.
Ocular sarcoidosis can cause intermediate or posterior uveitis and vitritis. The suspended inflammatory aggregates can become symptomatic floaters.
Supporting reference: Vitritis from inflammatory disease is an established mechanism for vitreous opacities and floaters.
Depositional, Degenerative and Malignant Causes
26. Primary Vitreoretinal Lymphoma (PVRL) — Important Masquerader.
Malignant lymphoma cells can infiltrate the vitreous and appear clinically like chronic vitritis. Patients commonly report floaters and painless vision loss.
Full reference: Reichstein D. Primary vitreoretinal lymphoma: an update on pathogenesis, diagnosis and treatment. Curr Opin Ophthalmol. 2016;27(3):177-184. doi:10.1097/ICU.0000000000000255. PMID: 26859131.