Issue 15.16
You may sometimes see small specks or clouds moving in your field of vision. These are called floaters. You can often see them when looking at a plain background, like a blank wall or blue sky. Floaters are actually tiny clumps of cells or material inside the vitreous, the clear, gel-like fluid that fills the inside of your eye. While these floaters look like they are in front of your eye, they are actually floating inside it. What you see are the shadows they cast on the retina (which is like the film in a camera). Floaters can appear as different shapes, such as little dots, circles, lines, clouds or cobwebs. The vitreous is important during ocular development as it forms a scaffold around which the essential structures form. (Remember back to scouts when you constructed a head or mask with paper mache’ around a balloon—once the paper mache’ hardened who cared if the balloon deflated). Similarly once the eye is formed the vitreous has done its job. As we grow older, it is more common to experience floaters as the vitreous gel changes with age and pulls away from the inside surface of the eye.
When the vitreous gel pulls on the retina, you may also see what look like flashing lights or lightning streaks. These are called flashes. You may have experienced this same sensation if you have ever been hit in the eye and seen “stars.” The flashes of light can appear off and on for several weeks or months.
The retina is the light-sensitive tissue lining the back of our eye. Light rays are focused onto the retina through our cornea, pupil and lens. The retina converts the light rays into impulses that travel through the optic nerve to our brain, where they are interpreted as the images we see. A healthy, intact retina is key to clear vision.
Usually, the vitreous pulls away from the retina without causing more problem than a few light flashes. In 8-10% of cases, however, the vitreous pulls hard enough to tear the retina in one or more places. Fluid may pass through a retinal tear, lifting the retina off the back of the eye — much as wallpaper can peel off a wall. When the retina is pulled away from the back of the eye like this, it is called a retinal detachment.
A retinal detachment is a very serious problem that almost always causes blindness unless it is treated with detached retina surgery. Thus every person that experiences a new onset of floaters or flashes should be evaluated urgently by an Ophthalmologist to rule out a detachment.
The human eye is reasonably fast, adept at detecting contrast, and surpassed in resolution only by birds of prey—a good all-around eye for the most versatile animal of all. Our job is to keep it healthy and functioning well.
For questions and eye consultation contact Richens Eye Center 435-414-8610.