Eye Floaters (cont.)
IN THIS ARTICLE
Eye Floaters: Pathologic Causes
Pathologic etiology: Similarly, the anterior vitreous attachment or vitreous base in toward the front of the eye can exert tractional forces on the underlying peripheral retina. A similar cascade of events can occur as seen posteriorly or in the back of the eye. However, anterior vitreous traction will usually not result in a separation or detachment of the vitreous, since the attachment of the vitreous to the underlying retina at the vitreous base is much stronger. This vitreo-retinal traction may pull on the thin anterior retinal tissues strongly enough to create a small hole in the retina. These holes are often associated with a flap of elevated retina still attached to the vitreous base. These holes often create a horseshoe shape around the elevated flap of retinal tissue. These peripheral retinal holes may cause a small amount of blood to escape into the vitreous cavity, which to the patient looks exactly like a benign posterior detachment floater. These small anterior vitreous hemorrhages produce unmistakable signs for the examining eye doctor and frequently necessitate a punctual repair of the retinal hole.
Left unattended, an anterior retinal hole or horseshoe tear can allow vitreous cavity fluid to accumulate under the retina. As this fluid progresses into the retinal tissues surrounding the hole, a retinal detachment can occur. This serious complication may require major surgery to restore the retina to its normal attached configuration. Left to its own devices, a retinal detachment can lead to certain blindness. Some patients are more at risk for anterior retinal hole formation and subsequent detachment. These patients include those with previous eye trauma or injury, previous eye surgery, high myopia or nearsightedness beyond 6 diopters, certain degenerative retinal conditions, diabetes, bleeding or clotting disorders, some systemic inflammatory diseases such as rheumatoid arthritis, and patients with other ocular diseases such as glaucoma.
Bleeding into the vitreous cavity may also result from conditions other than anterior retinal holes. The most common cause of vitreous hemorrhage is proliferative diabetic retinopathy, or PDR. This condition usually follows a long course of poorly controlled diabetes which allows abnormal blood vessels to grow in the retina. Eventually when left undetected or untreated, these abnormal fragile vessels actually grow into the vitreous cavity and bleed spontaneously. PDR must be treated by a qualified ophthalmologist with a wide variety of sophisticated measures, including injections, lasers, and surgery. Untreated PDR inevitably leads to blinding complications. A diabetic vitreous hemorrhage may absorb or regress of its own accord, or remain persistently in the vitreous cavity, obscuring the view of the abnormal underlying retina. Persistent vitreous hemorrhage may necessitate surgical removal by a technique called pars plana vitrectomy (PPV) or simply vitrectomy. This advanced procedure is accomplished by a vitreo-retinal surgeon using an operating microscope and 3 microincisions into the vitreous cavity through the pars plana. The pars plana is a circular band of tissue about 3 to 4 millimeters behind the cornea. Because the pars plana contains no major blood vessels and no retinal tissue, safe access is available to the surgeon.
A number of other conditions can less commonly produce vitreous floaters, including hemorrhagic macular degeneration, retained foreign bodies, postoperative matter, or rare parasitic infections, more common in third-world nations.
John D. Sheppard, MD, MMSc
David M. Salib, MD
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