We often take good vision for granted, until something unexpectedly changes.

One of those moments is when all of a sudden black floaters in the shape of cobwebs appear out of nowhere.

Sometimes these are associated with flashing light sensations.

These symptoms are usually a sign that the vitreous , the gel-like body that is at the center of the eye and is positioned against the retina, shrinks and pulls away from the retina.

It is called a vitreous detachment and is part of the normal aging process of the eye.

Usually a small floater develops and that is the end of it, vision remains unaffected.

Sometimes the vitreous gel retracts but hangs on to a small part of the retina and causes it to tear.

If an adjacent blood vessels tears in the process, blood enters the vitreous and the floaters are more prominent.

A retinal tear often causes liquid vitreous to get underneath the retina and next a retinal detachment develops.

The patient will notice loss of part- or all of the vision.

This is an urgent medical problem and requires surgery to correct.

If the retina is torn, but has not detached, a laser treatment to the tear will be sufficient to avoid getting a retinal detachment.

If the retina already is in the process of detaching, more surgery is needed.

Sometimes it is possible to reattach the retina by injecting a small gass bubble in the eye which closes the tear and pushes the retina back in place, followed by a laser treatment to the tear.

This is a procedure that can be done in the office.

In more advanced cases of retinal detachment more invasive procedures need to be done in the operating room.

This includes removal of the vitreous gel, or the placement of a silicone rubber strip around the eye, or a combination of the two.

Gel can be replaced with saline, gas or silicone oil, depending on the type and severity of the retinal detachment.

At an increased risk to develop tears and detachments are patients who are nearsighted, or who have family members with a retinal detachment.

Another important risk is prior cataract surgery or eye injury.

Anyone who suddenly experiences flashes and floaters should see their eye doctor for a detailed examination of the vitreous and retina through a dilated pupil.

Erik van Rens, MD