Diseases
Overview
Age-Related Macular Degeneration
Diabetic Retinopathy
Retinal Vein and Artery Occlusions
Flashes of Light and Floaters
Retinal Tears and Retinal Detachments
Macular Pucker (Epiretinal Membrane)
Macular Hole
Vitreomacular Traction
Uveitis (Inflammation in the Eye)

Flashes of Light and Floaters

What causes Flashes and Floaters?
The retina is the light sensing tissue that lines the interior wall of the eye. Inside the main body of the eye is the vitreous gel and the gel is adherent to the surface of the retina. As a normal process of aging, the vitreous begins to degrade and consolidate causing it to shrink, liquefy, and eventually separate from the retina. During this process, a mechanical pulling force is applied to the retina causing stimulation that gives the sensation of flashing lights known as photopsias. When the gel is separated from the retina it will cast a shadow that is seen as a floater and can take the shape of a speck, line, dot, circle, or spiderweb. The onset of flashes and floaters indicate that there is an active process of posterior vitreous detachment from the retina.
 
Why do I need an exam for Flashes and Floaters?
In many patients the process of posterior vitreous detachment will undergo its completion without symptoms, in those with symptoms there is a 10-12% risk of developing a retinal tear. A tear in the retina can occur when the vitreous gel pulls on an area of weak retina or in an area that is abnormally adherent. If a tear occurs, it is typically far in the peripheral retina and will not affect the vision. However, fluid can migrate through a tear causing the retina to detach from the wall of the eye. Retinal detachments can cause vision loss and require surgery to treat. If the retinal tear is identified early it can be treated to prevent a retinal detachment. The vitreous detachment can take several weeks to complete its course. During this process there is ongoing risk of developing a retinal tear, though the risk is highest at the onset and decreases with time. 
 
What causes a Vitreous Detachment?
While the process is natural part of the eye aging, certain condition can accelerate the process. Patients with high myopia, have had trauma to the eye, undergone cataract extraction or other intraocular surgery, have had YAG capsulotomy are at risk of having an acute posterior vitreous detachment. When the vitreous detaches secondary to one of these causes, there is an increased risk of developing a retinal tear.
 
Are all flashes and floaters a sign of something wrong?
Not all floaters are caused by a vitreous detachment. The vitreous gel can consolidate and cast a shadow that causes floaters without detaching from the retina. These floaters can be present since a young age but are typically small and do not indicate any risk to the retina. Intraocular inflammation (Uveitis) can also cause floaters due to clumps of inflammatory cells inside the eye. Inflammation typically is associated with eye pain, sensitivity to light, and redness.
 
Not all flashes of light are caused by a vitreous detachment as well. Occasionally, photopsias can be caused by an ocular migraine. In this case, the retina is not being stimulated mechanically or by light but the sensation is caused by a spasm of the blood vessels in the visual cortex of the brain. These are typically bright, geometric, and multicolored but can also present as a dark spot. The standard pattern is for the lights to start small and increase in size over the course of 20-30 minutes then begin to dissipate and can be associated with or without a headache.

It is difficult to differentiate the cause of flashing light or floaters based on symptoms and a thorough exam is indicated to evaluate any symptoms.
 
What can be done about the floaters?
When the floaters first appear they cast a shadow from being very close to the retina causing the shadow to be very dark and dense, as time passes, the gel moves away from the retina and the shadow becomes less dense.  The floaters will never go away completely but as the darkness of the shadow decreases and time passes they become less and less bothersome. The only reliable treatment is to surgically remove the floaters with a Pars Plana Vitrectomy. While this can be done, it involves a surgery that carries with it risks and should be a last resort for floaters that are significantly affecting the vision and ability to function normally.
Dr Kruti Dajee Dr Jawad Qureshi Dr Johnathan Warminski