The eye is a sphere with fluid separated into three parts. The whites of the eyes are called the sclera. The middle outermost part is the cornea, a transparent membrane that allows light rays to pass into the eye. Through the cornea, you can see the iris, which is the colored portion part of the eye. The iris contains muscles that change the size of the pupil, the opening in the center where light passes through and hits the lens.
As light passes through the cornea, it passes through the anterior chamber, which is filled with a clear watery fluid that provides nutrients to the lens and surrounding structures. As the light continues its path from the lens to the back of the eye, the retina, it must travel through a thick gel-like substance called the vitreous humor, which makes up most of the eye’s volume and helps give it its spherical shape.
As we age, the vitreous thickens and can sometimes shrink. Sometimes clumps or strands build up in the vitreous since it contains cells that remove some blood and other debris that can interfere with light being transmitted to the retina causing shadows. These are termed floaters, and can look like bubbles, bugs, cobwebs, or dark spots that move with your eye movements. When the vitreous shrinks and pulls away from the retina in the back of the eye, it is called a posterior vitreous detachment. Floaters are usually the first symptom that you will observe with this condition.
Posterior vitreous detachments can occur as we age since the vitreous tends to shrink. Other risk factors include being nearsighted (you need glasses to see far away), having a history of trauma to the eye, having had previous eye surgery (like cataract surgery or LASIK surgery), or having an inflammatory condition in the eye. In some cases, a posterior vitreous detachment can lead to a retinal detachment as well. If left untreated, this can ultimately lead to blindness. Other eye conditions that can cause floaters include posterior uveitis, which is inflammation of the uvea, or the middle part of the eye that contains the iris and retinal tears or detachments. Floaters in your visual field may also be related to other conditions that may not be caused by problems with your eyes alone, like migraine headaches with auras.
If your doctor diagnoses you with a posterior vitreous detachment, you will need to see an eye specialist for a complete dilated eye exam and to carefully examine every aspect of your eye with a special lamp called a slit lamp to rule out a retinal tear or detachment.
With any changes in your vision, it is important to always contact your doctor and get regular eye exams by an optometrist or an ophthalmologist. If you are concerned about any changes in your vision and have posterior vitreous detachment, you will be counseled on the severity of your disease and the best treatment option.
Gabriel Espinoza, MD, has experience in caring for patients in critical care, primary care, and emergency settings. Some of the topics he has focused on in his medical career include public health, pediatrics, wellness, and fitness. He has co-authored a chapter on the utility of point-of-care ultrasound in the diagnoses of eye conditions. The content written by Dr. Espinoza is for information and educational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician with any questions you may have regarding a medical condition.
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