The Good News and the Bad News About Eye Floaters
The Good News
I’ve always been a good news first type of guy. Well, here it is: If the vitreous humor has already pulled off of the back of the eye safely, it won’t be under tension and will not pull the retina off the back of the eye. So, no retinal detachment. This is called a PVD (posterior vitreous detachment).
You can think of the interface between the vitreous and retina like plastic wrap: it’s clingy. If it’s already pulled away from its normal position where it pushes the retina flat, it won’t rip or tear holes at it starts to shrink. This type of pulling causes a common condition in the ERM, or epi-retinal membrane, which can tear in the center of the retina’s vision, creating a ‘Macular hole.’ I’m sure you realize you don’t want a hole in the middle of your vision. It is possible to self-monitor for this by using an Amsler Grid. The wrinkling that occurs where the retina and vitreous interface causes scar tissue to form. To get an idea of how this occurs mechanically in the eye, just lift up your sleeve and notice how it wrinkles.
The Bad News
Now we’re on to the bad news. That is, if you have a posterior vitreous detachment (PVD), the floaters in your eyes are more noticeable. In general, eye floaters are more visible in a bright background which has a lot of contrast.
The most common posterior vitreous detachments form a ring over the head of the optic nerve. This is called a Weiss’s ring. The shape of the ring is caused by the release of attachments at the rim of the optic nerve head. This ring is often significant visually, and is far larger and more condensed than your classic floaters. The more classic type of eye floaters are stringy with undefined shapes. Also, a typical eye floater is more often mobile than the ring-shaped one. In general, a person who has a posterior vitreous detachment has greater risk for retinal detachment (RD) – this is because they are experiencing changes in vitreous humor already.