The eye is supposed to be round like a tennis ball, but some people’s eyes are more suited to football than tennis. If the clear front part of the eye, the cornea, is somewhat elongated, vision isn’t as sharp as it should be. This condition, known as astigmatism, used to be difficult to treat, but new technologies in glasses, contact lenses and corrective eye surgeries have changed that.
Dr. Sean Mulqueeny of Mulqueeny Eye Centers offers a more technical explanation: “Astigmatism literally means ‘without one point.’ Light entering the eye focuses on two points. This is what separates astigmatism from other refractive errors that have a single point of focus. The light bends to two points, typically at the anterior corneal surface (front wall of the eye).”
Nearsightedness and farsightedness are other common refractive errors; however, as Mulqueeny notes, these problems still allow light to pass through the eye at a single point of focus. In the case of nearsightedness, the light is focused in front of the retina, while farsightedness causes light to focus behind the retina.
“Having astigmatism is very common. Probably at least 70 percent of people have some corneal astigmatism,” says Dr. Jay Pepose, medical director of the Pepose Vision Institute. He says young people tend to have corneas shaped like a vertical football, noting that the football becomes horizontal over time. “As you get older there’s a drift in the opposite direction,” he explains. The cause is not known, although one theory is that blinking for a lifetime can slowly change the shape of the cornea.
“Since astigmatism means that there is warpage in the visual system, correcting it with glasses requires that we incorporate a corresponding, but opposite or negative warp in the spectacle lens to neutralize this warpage,” Mulqueeny says. “Soft contact lenses work in a similar way. Rigid gas permeable (RGP) or hard lenses ‘mask’ this warpage by essentially smoothing the front surface on top of the cornea. In most, if not all, cases of irregular astigmatism, and in higher amounts of regular astigmatism, RGP lenses are preferable.”
Mulqueeny also treats patients’ astigmatism with a newer type of contact lens, known as a hybrid lens. The hybrid lens has a RGP center to maximize visual acuity, wrapped in a soft lens for comfort.
Refractive surgery is another option. “Astigmatism can be treated through laser vision correction, like LASIK, where we reshape the cornea and make it round,” Pepose says. Advances in laser technology have made these procedures extremely accurate and reduced the rate of complications.
Another surgical approach is lens implantation, which is often performed to remove cataracts. When the clouded lens is removed, a new lens can be implanted that corrects refractive errors, including astigmatism. For many people, the surgery provides their first chance to see clearly without glasses or contact lenses in decades.
Mulqueeny sums up: “Many patients have had tolerated sub-par acuity due to their astigmatism. It shouldn’t be that way any longer. Advances in technology, including for glasses, contact lenses and refractive surgery, have opened up new options for these patients offering superior visual results.”