In previous blogs, I have generally covered visual problems secondary to head injuries that are related to the brain. Obviously, there are vision problems related to direct trauma to the eye, but that has not really been the purpose of my blog. These direct eye injuries have already been documented by many other authors.
Floaters fall somewhere in between.
What are floaters?
A patient usually describes them as dark spots, lines, or spider webs floating in his/her vision. They don’t exist in the real world, but are often described as annoying flies dancing about. I’ve had patients admit they swat at them. We have all seen floaters occasionally, like when we stare up at a blue sky or white wall.
Floaters are actually tiny clumps of solid material floating around in the back of the eye in a thick fluid called the vitreous.
The vitreous lies just in front of the retina (the retina is the part of the eye that actually senses light and sends signals to the brain). The vitreous cavity is filled with a clear, thick, jelly-like substance which is important to the structure of the eye. Click here to learn more about floaters.
What is important to know is that solid particles (sort of like planets in space) can dance around in this gel and be quite annoying to the patient.
After head trauma, the eyeball can be shaken up, dislodging these little particles. An individual can experience a single spot or a shower of floaters. This can occur in one or both eyes. Floaters are common complaints after whiplash or head trauma in motor vehicle accidents and probably occur in at least 10% of head injury patients. These same patients will also frequently complain of flashing lights. Flashing lights and floaters often go together.
When asking a head injury victim about floaters and flashes, that person will frequently not volunteer the information. Patients think it makes them appear a little wacky in front of the questioner. However, I am a well-trained eye care professional, and I always ask this question.
Floaters can indicate hidden retinal tears which can lead to retinal detachment and permanent loss of vision. An ophthalmologist such as myself can perform a detailed dilated exam of the edge of the retina to look for tears. Small tears are not easy to find. But checking for hidden tears is part of the eye exam and must be performed on every patient experiencing floaters and flashes. Small tears detected early can be easily treated with a laser (this can only be done by an ophthalmic surgeon) and prevent future retinal detachment. I have treated hundreds of patients with retinal tears over the course of my 30-year career.
Prevention is the key- retinal tears treated early stop visual loss later. These patients’ symptoms cannot be ignored, and only a thorough exam of the peripheral retina using special techniques and instruments can discover these tears. All head injury patients must at the very least be asked if they have floaters or flashes. Flashes actually come from the vitreous pulling upon the retina- the more floaters or flashes means a greater likelihood of finding a tear.
Even if no tear is initially discovered, patients need to be advised on future symptoms of retinal detachment, and the importance of early detection.
People can obviously have floaters and have no retinal tear- can anything be done?
The answer is generally no- floaters, even if seen by the examiner cannot be safely zapped with a laser. The danger to the eye is too great and patients are often told to ignore floaters. Once an individual is reassured that a retinal detachment is not present, floaters become less troubling. But floaters can become chronic, and just because they can’t be treated doesn’t mean they shouldn’t be documented. Unfortunately, many symptoms after head injuries are difficult to treat but still interfere with daily function- the eyes are no less important.
Can floaters or flashes come from anything besides the eye in head trauma patients?
The answer is yes- this makes it even more confusing. We’ve all struck our head at some point in our lives and seen stars.
Trauma directly to the brain can often cause unusual visual symptoms– constellations of lights, colored lights, or wavy lines. These can be difficult to distinguish from floaters or flashes coming directly from the eye. A careful history by an eye doctor is critical.
Visual symptoms coming from the brain are common. Migraine sufferers often see shimmering lights (called a migraine aura) just before the headache begins. These patients sometimes experience blind spots in their vision.
Head trauma can frequently cause headaches or make previous migraine sufferers have more frequent visual symptoms so the picture can be confusing, but that is why the eye exam is so important. A good eye doctor thinks about the eye and brain together, just like a good family doctor thinks about the whole body.
Headaches after head injury will be another subject for a separate blog.
The key message is all head injury patients should be asked about floaters and/or flashes- if they have symptoms, they need a thorough exam.