Nearsightedness, Farsightedness, & Astigmatism: Which is Which?
When we write a prescription for glasses or contact lenses, it’s usually because they have difficulty seeing from long distances, short distances, or their vision is distorted. In the world of ophthalmology, we call these treatable eye conditions “refractive disorders”, meaning that light enters the eye and is sent to the wrong place in the eye causing the brain to interpret the image unclearly.
The three major types of refractive disorders are nearsightedness, farsightedness, and astigmatism. These disorders are commonly confused with each other, so we broke them down to help you understand your lens prescription better.
What is Nearsightedness?
Nearsightedness (also referred to as myopia) is a refractive disorder in which you can see close up objects clearly, but have difficulty seeing objects that are farther away, like road signs. This most commonly happens when the eyeball is too long, which causes light rays to hit a point in front of the retina instead of directly on its surface. Nearsightedness also happens when the cornea or lens of the eye is too curved for the eyeball’s length. Sometimes it’s all of the above.
What is Farsightedness?
Farsightedness (also referred to as hyperopia) is a refractive disorder in which you can see distant objects clearly, but have difficulty seeing objects that are close up, like words on a page. This happens when the eyeball is too short, which causes light rays to hit a point behind the retina instead of directly on its surface.
What is Astigmatism?
Astigmatism is probably the most misunderstood refractive disorder. People with astigmatism experience blurred vision, eye strain, and headaches after prolonged periods of visual stimulation, like reading a book, working on a computer, or watching a movie. Astigmatism happens when the cornea is shaped abnormally instead of having the normal symmetrically round shape. Because of this, light rays entering the eye hit multiple points behind and/or in front of the retina instead of directly on its surface. Astigmatism can also happen when the lens is shaped abnormally and is called lenticular astigmatism.
Treatment Options for Refractive Disorders
Glasses or contact lenses are the most common treatments recommended for refractive disorders, but LASIK eye surgery is also a popular option. Glasses and contact lenses correct the way light rays enter your eye and directs them to the retina’s surface. LASIK is a more permanent solution as it corrects the actual shape of your eye. Read more about LASIK eye surgery in 3 Types of Eye Surgeries That Will Help You See Better.
If you’re experiencing vision problems, it’s important to schedule an appointment with your ophthalmologist to have your eyes examined. At Baptist Eye Surgeons, we treat a wide range of eye disorders as one of the most trusted eye specialists in Tennessee. To request an appointment or get directions to our Knoxville and Morristown locations, visit our website.