Can you tell me the difference between eye floaters and entoptic phenomena?

Yes: Vitreous is the jelly-like substance in the middle of the eye that undergoes normal changes with age and peels off the retina in the back of the eye. Debris in the vitreous (like blood) or clumping of the vitreous blocks the light passing through the eye; these perceived shadows are floaters. Entopic phenomena are flashes of light that occur as the peeling vitreous tugs on the retina.

Normal v. abnormal: Entoptic phenomena are patterns and sensations which are part of the normal visual system which is not perfect. Floaters are objects introduced into the visual axis which can be seen in certain light circumstances. While floaters are not usually harmful, they can be annoying and may be a first sign of a problem. Consult with your ophthalmologist to sort these out.