Uh oh! Flashes and floaters!!!

Dear Dr. Weaver,

A few days ago, I experienced an episode of flashing lights that lasted for a few seconds. The flashes have since gone away, but now I see a very large, annoying dark spot in my vision, which moves back and forth, but never goes away. What’s going on?

Sincerely,
Becky

******************************

Dear Becky,

Any symptoms of new floaters or flashing lights can be a result of serious conditions involving the retina. So if you have not seen an eye professional regarding this, please do so immediately.

Floaters are usually a result in a change of condensation of the vitreous, which is a clear gel-like material housed within your eye. The vitreous gel is formed in your eye since birth, and some changes can occur to that gel as you age. Once a uniform, consistent material, portions of the vitreous can “break-down” and “pull-away” from the retina in the back of the eye. When light enters the eye, the areas of condensed vitreous develop faint shadows on your retina. Most people notice small dark specks or strands that move back-and-forth in their vision. The reason for this is because the vitreous is freely movable inside the eye, which allows the “floaters” to bounce around or “float” in your visual field.

Most people who are nearsighted (myopic) commonly have floaters, due the anatomy of their eye. The floaters are highlighted most when looking into the sky, peering at a computer screen, or when reading a book or magazine. After a period of time, the brain develops the ability to ignore the annoying floaters. However, the formation of any new floaters is of concern.

The most common condition affecting the vitreous due to aging is called a Posterior Vitreous Detachment, or PVD. The initial symptoms include repeated flashes of light followed by the formation of a large, globular or ring-shaped floater. I mentioned before that the vitreous is freely moveable in the back of the eye, but it is attached to a few areas of the retina. One of these locations is near the optic nerve. As the vitreous pulls away from the area near the optic nerve, the tugging or traction causes the appearance of flashing lights. Once the vitreous finally pulls away, there is no more traction, so that is why the flashing light subsides. But once the vitreous does pull away, there is a large area of condensed vitreous that contributes to the large floater. This floater is very annoying, because it is new and it is very close to the center of your vision. The floater does not go away; it is there indefinitely, but your brain learns to ignore it over time, which can take weeks to months.

The major concern when people notice flashes and floaters are that those symptoms could reflect a serious problem occurring with the retina. The three main conditions are retinal holes, retinal tears and retinal detachments.

A retinal hole is a small opening in the retina, which could be caused by trauma or the tractional force of the vitreous. The formation of a retinal hole can cause a brief flash of light, followed by a floater. However, these changes usually occur at the edge of the retina and do not always show any symptoms. The symptoms and causes of a retinal tear are also similar to that of a retinal hole, but the flash of light may appear more light a lightening streak. Treatment for either can include monitoring the area, but is usually involves the application of laser treatment around the hole/tear to seal it off from causing a retinal detachment.

A retinal detachment is a serious eye condition that is vision threatening. This is when the retina actually lifts off from the back surface of the eye. With a retinal tear or hole, fluid can actually seep through the opening of the retina and lift it off. When this occurs, symptoms can include flashes, a large shadow and/or loss of vision. Referral to a retinal specialist is recommended immediately for surgical repair, but if vision is affected, there is a possibility that the vision may not be restored to its original state.

Flashing lights do not always indicate a problem with floaters or the retina, but it usually does. Dryness from contact lenses, the optical material of eyeglasses, cataracts or any diseases or dystrophies of the cornea, can contribute to an uneven focusing of light, depending on the angle at which the light enter the eye. The type of small flashes associated with this is usually only noticed at night or dark environments, but not always.

If you are experiencing any light flashes or floaters that seem new or unusual, it is urgent that you obtain a comprehensive eye examination, including dilation. The dilating drops allow the eye doctor to get a more complete view of the retina and the back of your eye. He/she may then diagnose your symptoms more appropriately and refer you to a retinal specialist if any treatment is needed.