FLASHES AND FLOATERS
written by Dr. William McSwain
WHAT CAUSES FLASHES AND FLOATERS?
Much of the eye is filled with a jelly-like substance called the vitreous. As you age, the vitreous starts to liquefy and separate from the retina. Clumps or strands of cells may form in the vitreous. When light passes through the vitreous, these strands cast a shadow on the retina resulting in the appearance of floaters. Floaters may dissolve over time or your brain may learn to tune them out of your vision. If they are really interfering with your vision, floaters can be removed with either laser treatment or surgery. These procedures are only performed for severe cases. Floaters can also have more serious causes such as vitreous hemorrhage, uveitis, retinal tear, or retinal detachment.
The retina is a light sensitive tissue. Any mechanical stimulation of the retina results the appearance of flashes of light in your vision. If the vitreous is pulling or tugging on the retina, you may experience flashes of light. Flashes may also occur with migraines.
WHAT IS A POSTERIOR VITREOUS DETACHMENT?
As you age, the vitreous starts to liquefy. Eventually, it begins to detach from the retina. As it detaches, the vitreous may pull tissue forward off the retina resulting in the appearance of floaters in your vision. The vitreous may tug or pull on the retina resulting in flashes of light in your vision. If there are any weak areas in the retina, a tear or break may develop. If a retinal tear is not identified and treated, it may develop into a retinal detachment which is an emergency requiring surgical repair to prevent permanent vision loss or blindness. Retinal tears are treated by laser, cryopexy (freezing the retina surrounding the tear), or by injecting an air bubble into the eye.
Posterior vitreous detachments are a normal part of aging. They most commonly occur in your mid-60’s. If you develop a posterior vitreous detachment, you need a dilated eye exam to identify any retina breaks or tears that need to be treated to prevent a retinal detachment. You are at higher risk of developing a retinal break or tear during the first 4-6 weeks after a posterior vitreous detachment begins. There are no restrictions on activity during this period. If you develop new floaters, persistent flashing lights, a curtain in your vision, or any changes in your vision, call our office immediately to make sure you have not developed a retinal tear or detachment. Regardless of your symptoms, you need to have another dilated exam 4-6 weeks after the onset of a posterior vitreous detachment to make sure you have not developed any breaks or tears.
ADDITIONAL READING: https://nei.nih.gov/health/floaters