Flashes and Floaters: An Overview
This article is intended to teach you about one of the most common symptoms that I see in my practice: flashes and floaters. This phenomenon can be very disturbing and worrisome to my patients until I can complete a full exam and confirm the etiology of the flashes and floaters. The most common cause of flashes and floaters is the Posterior Vitreous Detachment. Here, I describe this phenomenon and demonstrate why a retina specialist should be involved in a “flash ‘n’ floats” patient.
BLUF (Bottom Line Up Front): New flashing lights or floaters need to be evaluated by an ophthalmologist (preferably a retinal specialist) for retinal tears or detachments.
Main Points:
Flashes and floaters are often caused by a posterior vitreous detachment (PVD)
70% of the population at some time will have a PVD
4% of those patients with a PVD will have a retinal hole, tear, or detachment
Retinal tears can mostly be addressed in the office with a laser procedure
Retinal detachments will need more invasive procedures or surgery to restore vision
Most complications from a PVD will arise in the first month after onset
Sudden flashing lights and new floaters are frequently experienced by patients and are quite alarming. This phenomenon is often caused by a Posterior Vitreous Detachment (PVD) where the jelly in our eye (called the vitreous) separates from the retina (the tissue in the back of the eye that is responsible for sending light signals to the brain). PVDs occur in approximately 70% of people, and hence, flashes and floaters are a frequent complaint. The vitreous is made up of 2% Type II collagen & hyaluronic acid, and 98% water. As the collagen and hyaluronic acid degrade (typically as we age), the vitreous will collapse on itself and pull away from the retina.
The flashing lights are typically caused by the vitreous physically separating from the retina. The retina is pulled on by the vitreous, stimulating the photoreceptors, and sending light signals to the brain. A patient may experience one really big floater. That floater tends to be the “collar” of collagen around the optic nerve. We call this big floater a Weiss Ring. Long skinny floaters are typically the collagen fibers bunching up on themselves. A “fog” that moves about in the eye is sometimes referred to as vitreous condensations and can be very visually disturbing. A shower of small floaters (called tobacco dust and may appear to the patient like a black snowstorm) may be blood or retinal pigment being liberated from under the retina during a retina tear. Approximately 4% of those patients with a PVD will have a retinal tear or detachment.
In the case of a retinal tear, most can be addressed in the office with a laser procedure to “weld” the retina together around the tear to prevent a detachment. However, if there is a detachment, a more aggressive approach must be taken. Some can be fixed in the office with a small bubble injection into the eye followed by laser whereby other detachments need proper surgery to reattach the retina to preserve vision. Hence, why an examination by a retinal specialist upon new flashes or floaters is strongly advised.
If a patient has a PVD with no retinal complications (like a hole/tear/detachment), they may be left with the floaters. Most of the time, the vitreous will continue to collapse and fall toward the bottom of the eye making the floaters less noticeable or only at the top of the vision. Other times, the brain will become accustomed to the floaters and learn to ignore them. Often the flashes subside since the retina is no longer being mechanically stimulated by pulling vitreous. Patients may notice that when they move their eyes (especially at night) they will see a “flash” which is light bouncing off of the vitreous body and will appear as a “shimmer.” However, sometimes floaters persist and they can be visually debilitating.
If the patient is noticing the Weiss ring in their vision, this can be safely and effectively lasered with a special neodymium-doped yttrium aluminum garnet (Nd:YAG) laser in the office. This infrared laser mechanically disrupts the collagen fibers breaking them up and often “vaporizing” them. This in office procedure leaves the patient with a significant improvement in the bothersome floater. However, when there are numerous smaller floaters or vitreous condensations, a vitrectomy may be recommended by a vitreoretinal surgeon (such as myself).
A Pars Plana Vitrectomy (PPV or simply known as a vitrectomy) is a very common surgical procedure. Nearly every retina surgery performed begins with a vitrectomy. Whether it’s a retinal detachment, peeling membranes, repairing a macular hole, or removing shrapnel; the first step is a vitrectomy. That’s because the vitreous can be removed without compromising the eye’s integrity. Therefore, when it comes to visually significant floaters or condensation that cannot be resolved with a Nd:YAG laser, vitrectomy is the definitive treatment.
