Duncan Eye

Flashes and Floaters

also known as Posterior Vitreous Detachment

What are floaters?

At some point in their lives, many people notice what looks like small specks of dust or wispy threads drifting across their vision. Some people describe them as seeing "bugs" or "spider webs". They notice that blinking does not get rid of these specks or threads and that when the eye moves, these specks or threads move as well. These are called floaters.

What causes floaters?

The posterior three-fourths of your eye is filled with a jelly-like substance called the vitreous. As we age, the vitreous tends to become thicker and may shrink. This thickening can lead to clumping of the vitreous gel. When in bright lighting, these clumps cast shadows on the retina, which are perceived as floaters. They are most visible when viewed against a background of a white wall or piece of paper.

What is the treatment for floaters?

Vitreous floaters are generally not treated, but instead are monitored by your eye doctor for any possible future complications.

What is a posterior vitreous detachment?

Sometimes the vitreous gel can detach from the wall of the eye, forming a posterior vitreous detachment. A vitreous detachment alone is not a serious condition. However, if the vitreous creates a tear in the retina when it detaches, this tear can lead to a retinal detachment, which is a serious and vision-threatening condition. This is why it is very important to see your ophthalmologist when you first notice floaters and later if they change in size, amount, or are accompanied by flashes of light.

What causes flashes of light?

Some patients also experience the sensation of flashing lights. There are two common reasons for this symptom. The more common and less serious cause is an ocular migraine. These usually appear as jagged lines around your side vision. They typically last 10-20 minutes and may or may not be followed by a classic migraine headache.

The more serious cause of the flashing lights is a retinal detachment. This can happen spontaneously, as a result of head trauma (recent or remote), or because of the vitreous pulling on the retina as described above. It is important to catch a retinal detachment as early as possible since there is surgical treatment which can halt the progression of a retinal detachment. Early intervention results in the best possible visual outcome.

Why is it important to have a dilated exam to evaluate the vitreous?

The appearance of floaters and flashes increase as we age, especially as patients enter their 60's. It is important to visit your eye doctor if you experience a sudden onset of new flashing lights or floaters. In this situation your ophthalmologst will dilate your eyes in order to get a good view of the retina and vitreous to make sure everything is healthy and that there are no microscopic tears in the retina.