• floaters ( entopsia)
• are formed due to images shed on the retina by opacities in the vitreous
• can be caused by different types of vitreous opacities like (1)
  • red blood cells
  • inflammatory cells
  • tumor cells
  • amyloid
• they may cause a localised and faint impediment to sight
• present as fine dots,cobwebs,veils,strings or clouds (2)
• their perception depends on the following characteristics:
• size of the opacities
• optical density
• distance from the retina
• pupil size
• background (1)
• may be perceived to move as the opacities move within the vitreous
  • e.g ocular movements
• they may occasionally be the prelude to a retinal detachment

Reference:

• (1) Margo ,et al. Posterior vitreous detachment, how to approach sudden-onset floaters and flashing lights. Postgraduate medicine 2005;117 (3)
• (2) Gariano RF et al. Evaluation and management of suspected retinal detachment. American Academy of Family Physicians.