I just posted this in the "Eye Floaters" forum. I never had a permanent problem with floaters, but couldn't help become more interested when I read your post.
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There are times when I've had spots, but this was just temporary and I thought it was simply because my body was 'run down' (malnourished).
Traditional Chinese Medicine (TCM) says that the eyes are effected by the liver. http://tcm.health-info.org/Zang%20Fu%20foundation/Liver.htm
but there are other sites that say floaters are caused by the vitreous (gel) of the eyeball thickening and becoming 'warped' but USUALLY remaining harmless (SOMETIMES a detached retina). There is even one that says that mental training (distraction) can improve the condition. The suggestion that there could be a cause from sexual over exertion sounds almost humorous, but actually could contribute to that 'run down' feeling.