By Ryan DuBosar
Sometimes patients need to live with ophthalmic floaters, but any sudden progression needs immediate attention, said Stephanie Jones Marioneaux, MD, a cornea and external disease specialist, during a talk that will broadcast Thursday, April 29, at ACP’s Internal Medicine Meeting: Virtual Experience.
Floaters begin in the vitreous cavity of the eye, which is 98% water (the rest being collagen and protein fibrils). By age 50 years, the vitreous tends to contract and break down into its component parts, which are clumps and strands—what patients call floaters.
Acute events, such as shearing force from head and eye injuries, can also cause floaters to develop, Dr. Marioneaux said. The vitreous is attached to the eye globe loosely at the optic nerve and at two other peripheral locations. Once detached, instead of moving with the head or eye as shock absorber fluid would, the vitreous moves independently, lagging behind, she said. "This is why patients view these condensations of protein and collagen as floaters."
Patients describe floaters in myriad ways. Sometimes they describe what they see as being like spider webs or an amoeba, Dr. Marioneaux said. Floaters can be large and cast a shadow, which the patient might also report.
Another type of floater is the Weiss ring, resulting when a posterior vitreous detachment occurs around the optic nerve head. "People will see these things in their vision, and sometimes you see [patients appear] as if they're swatting flies," she said. Other conditions that can cause floaters include vitreous hemorrhage from proliferative diabetic retinopathy.
Other causes of similar symptoms include age-related macular degeneration, diagnosed on ophthalmoscopy when the macula does not have a crisp foveal reflex and the darker areas show subretinal blood. These patients will report shadows. More dramatic causes could include a large malignant melanoma within the eye, which the patient would perceive as an orange lipofuscin pigment.
Some exceptional causes call for action, but not every floater requires treatment, Dr. Marioneaux said. "What do we do about floaters that are benign? We do nothing, generally."
Exceptions include floaters so large they block the line of vision, which merit immediate referral to ophthalmology. "Even though the eye is quite large, you only have a single line of vision that originates in the fovea," she said.
If floaters don't cross the line of vision, they go unseen. "So that can be quite random," she said. "That's why patients feel that the floaters have 'gone away.' No, you're just very fortunate in that it did not cross the line of vision."
Dr. Marioneaux said she typically counsels patients that routine vitreous floaters do not go away. She recommends making a very clear mental note of the quantity and size of the floaters so that when patients see them again, even after a long time, they can simply check that they are the same size and number and not hit the panic button.
"If, however, this is a new onset of different floaters—so say they saw three and they were just sort of like clumps, and now they see hundreds of them and they're big blobs—well, that patient needs to absolutely be referred to the ophthalmologist," she said. ■