Nearsighted or Farsighted or Astigmatism?
Some people are born with great eyesight and it stays that way until presbyopia and its difficulty with close focus encroaches after their 40th birthday. Others develop either nearsightedness or farsightedness as they progress as children. And other people have astigmatism, which creates some degree of blurry vision at multiple distances. All of these conditions cause what are known as refractive errors, where the focus point of the image doesn’t fall directly on the retina in the back of the eye.
So what are these three vision problems?
Nearsightedness is clinically called myopia. It is the most common refractive error, where objects seen at distance are blurry. Myopia is usually caused by an elongation of the eyeball that occurs over time. With myopia, the visual image is focused in front of the retina, rather than directly on it.
Farsightedness is clinically called hyperopia. Not as common as myopia, hyperiopia allows the person to see objects at distance in focus, but up-close vision is blurry or the person needs to squint to focus. A shortening of the eyeball usually causes hyperopia. With hyperopia, the visual image is focused behind the retina.
Astigmatism is different than myopia or hyperopia. This is an imperfection of the cornea, preventing part of it from focusing light onto the retina. With astigmatism, the entire image won’t be blurry, but part of it may be. Astigmatism is caused when the patient’s cornea is shaped in more of an oblong shape than the round normal shape. With astigmatism, light rays fail to come to a single focus point on the retina. This can affect vision at all distances. Most people have at least some degree of astigmatism in their eyes, although it often isn’t enough to require correction.
All of these refractive errors can be corrected with eyeglasses, contact lenses, or refractive eye surgery by the team at Central Valley Eye Medical Group. Call us at (800) 244-9907 to schedule your next eye exam.
Posted in: Astigmatism