Eye Flashes and Floaters Evaluation

Flashes occur as a result of pressure on the retina, the bundle of nerves in the back of the eye where images are detected and transmitted to the brain. Such pressure causes patients to see either flashing lights or lightning streaks. Floaters occur when collagen fibers move across the vitreous and into the field of vision, causing patients to see specks, strands, webs or other shapes as the fibers cast shadows on the retina. Flashes and floaters are most visible when looking at a plain, light background.

Beyond simple aging, floaters or flashes appear most often in eyes that are injured, inflamed or nearsighted, and can be a result of the following:

• Cataract or YAG laser surgery
• Diabetes
• Retinitis
• Nearsighted vision
• Eye infections
• A blow to the head
• Injury to the eye
• Spasm of small blood vessels

Posterior vitreous detachment occurs when the vitreous gel separates from the retina. While PVD is usually a normal part of aging, it can occasionally lead to retinal tears.

A sudden increase in floaters, bright flashes of light, loss of peripheral vision, a curtain-like shadow, or sudden vision loss should be evaluated immediately because these symptoms may indicate a retinal tear or retinal detachment.

Most people who develop posterior vitreous separation or detachment (PVD) do not suffer further complications. For a small percentage of people, however, PVD can cause a retinal tear. A retinal tear is quite dangerous because it can lead to retinal detachment, which can seriously threaten vision. A sudden onset of symptoms, or momentary blindness in one section of the field of vision, is cause for concern. 

It is important that anyone experiencing unfamiliar disturbances in vision have an examination in which the pupils are dilated; this is the only way in which a retinal tear can be accurately diagnosed. If a retinal tear is identified, treatment can prevent the tear from extending to a retinal detachment.

For patients initially diagnosed as having uncomplicated PVD, a small percentage will go on to have retinal tears within 6 weeks, so it is important that they follow up with their doctors. For patients with underlying causative conditions, such as illness or injury, other treatments may be necessary.

Although flashes and floaters are usually harmless and do not need treatment aside from regular monitoring, patients bothered by disturbances in their vision, or those experiencing significant visual interference, require medical intervention.

When treatment is necessary to reduce the appearance of flashes and floaters, it requires surgery to replace the vitreous gel. This procedure, known as a pars plana vitrectomy, removes the natural vitreous and replaces it with fluid.

In the case of a retinal detachment, emergency treatment is necessary to prevent serious complications. With treatment, most patients, even those with retinal tears, are able to maintain healthy vision.