What are the causes of myodesopsia (floaters)?

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From the Guidelines

Black floaters in vision are typically caused by small clumps of gel or cells inside the vitreous, often resulting from age-related vitreous degeneration or posterior vitreous detachment (PVD) 1. The most common cause of black floaters is age-related vitreous degeneration, where the vitreous shrinks and becomes more liquid, allowing debris to clump together and cast shadows on the retina. Other causes include:

  • Posterior vitreous detachment (when the vitreous separates from the retina) 1
  • Eye inflammation
  • Bleeding in the eye from diabetes or hypertension
  • Retinal tears
  • Eye injuries Certain medications and eye surgeries can also contribute to floater formation. While most floaters are harmless and become less noticeable over time, sudden increases in floaters, especially when accompanied by flashes of light or vision loss, require immediate medical attention as they may indicate a retinal tear or detachment 1. Treatment is usually not necessary for routine floaters, but persistent, vision-impairing floaters might be treated with vitrectomy surgery or laser therapy (vitreolysis) in severe cases 1. Regular eye examinations are important for monitoring any changes in your floaters and overall eye health. It's essential to note that approximately 80% of patients who presented without detected breaks, and then had breaks occur subsequently, had either pigmented cells or hemorrhage in the vitreous or retina at the initial evaluation, or new symptoms that prompted a return visit to the ophthalmologist 1. Therefore, it is crucial to seek medical attention if you experience any sudden changes in your vision or an increase in floaters.

From the Research

Causes of Black Floaters

  • Black floaters are often associated with posterior vitreous detachment (PVD) 2, 3, 4, 5, 6
  • The presence of vitreous or retinal hemorrhage is a risk factor for retinal tears and detachment, which can cause black floaters 2, 3, 5, 6
  • A large number of floaters or a cloud-like appearance to the floaters can indicate a high risk of developing retinal tears 2, 3
  • Symptoms of visual impairment, such as subjective visual reduction or subjective field loss, can also be predictive of retinal tears and detachment 4, 6
  • The absence of flashes or floaters can be a predictive factor for retinal tears and detachment in some cases 4

Risk Factors for Retinal Tears and Detachment

  • Retinal or vitreal hemorrhage 2, 3, 5, 6
  • Large number of floaters or a cloud-like appearance to the floaters 2, 3
  • Symptoms of visual impairment, such as subjective visual reduction or subjective field loss 4, 6
  • History of previous PVD-related pathology 6
  • Duration of symptoms for less than 24 hours 6

Association with Posterior Vitreous Detachment

  • Posterior vitreous detachment (PVD) is a common cause of black floaters 2, 3, 4, 5, 6
  • The onset of flashes and floaters, and the presence of retinal and/or vitreous hemorrhage, are risk factors for the development of retinal tears in the setting of a PVD 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Predicting retinal tears in posterior vitreous detachment.

Canadian journal of ophthalmology. Journal canadien d'ophtalmologie, 2011

Research

Symptom-Based Risk Factors for Retinal Tears and Detachments in Suspected Posterior Vitreous Detachment.

Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde, 2022

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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