Spider webs, dancing threads, bugs, something flying, a moving mouse. Even a gecko. Steamboat Springs ophthalmologist Mark Helm, M.D., has heard his patients describe "floaters" in a variety of ways.
These small, shifting, shadowy shapes that some of us see can be merely annoying or may signal something worse. The sudden ap--pearance of one large floater or several smaller ones -- especially when accompanied by flashing light on the periphery of vision -- can signal a torn or detached retina.
The retina is a delicate layer of nerve tissue responsible for vision. It is sandwiched between the back of the eye and the vitreous humor, a clear, jelly-like material that makes up most of the inside of the eye.
With aging, the gel gradually liquefies and causes the vitreous humor to pull away from the retina. This process can, in turn, tug the retinal tissue away from the back wall of the eye. A small separation is called a tear. Sometimes a tear will cause a larger separation, or detachment, of the retina.
"It is very important to see an ophthalmologist any time a sudden vision change occurs," Helm said. "If you experience a sudden large floater, a number of new floaters, or arcs or flashes of light, it could be due to a retinal tear. Most tears can be fixed with laser treatment. A tear can progress to a detachment if fluid gets underneath the tear and lifts the retina from the back of the eye."
Retinal detachments are far less common than tears, Helm noted. A detachment typically begins on one side and moves across the eye, a process that can happen during a few hours or several weeks. Symptoms often include blurred vision, a sense of a dark shadow affecting vision or an impression of a curtain being gradually pulled across the eye.
A retinal detachment is a medical emergency that should be diagnosed and treated surgically very quickly after symptoms first appear, Helm said. When the retina becomes detached, there is a risk of permanent loss of vision in the affected eye. The extent to which sight can be saved depends on the location of the detachment and the amount of time that has passed since symptoms began.
"If you think you are experiencing a retinal detachment, see an ophthalmologist immediately or have someone take you to the hospital emergency department," Helm said. "You should seek medical attention as soon as the symptoms occur."
Factors that increase the risk of retinal problems include:
Advancing age. Retinal tears and detachments are more likely after age 50.
Trauma to the eye or head.
Myopia (nearsightedness). The globe of the eye is larger and the retina is thinner in the eye periphery of a nearsighted person.
On the rare occasions when Helm encounters a detached retina, he refers the patient to a retina specialist in Denver or Grand Junction for prompt surgery.
Awareness and prevention are the keys to avoiding vision loss. Helm recommends annual eye exams for everyone older than 60. Those between ages 40 and 60 should see an eye doctor every two to five years. People who wear prescription eyeglasses may want to have their eyes checked every year or two.
"A thorough eye exam involves dilation and looking at every aspect of the eye -- the cornea, lens, vitreous gel and entire retina," Helm said. "There can be a textbook worth of problems."
Scheduling regular eye exams, knowing the telltale signs of a tear and a retinal detachment, then acting promptly when symptoms occur literally may save your sight.