Astigmatism: Everything You Need to Know
Many people have astigmatism, but not everyone experiences it the same way. For many people, the effects of astigmatism are insignificant. Unfortunately, moderate or severe astigmatism can cause blurred vision, eyestrain, and headaches.
Astigmatism occurs when the cornea is shaped more like a football than a basketball. This prevents light from reaching the retina and results in poor vision. Astigmatism is usually genetic and present at birth, but it can also be caused by injury or disease. The best method for diagnosing and treating astigmatism is with a comprehensive eye exam.
What Is Astigmatism?
Astigmatism is when the lens or cornea of the eye is misshapen, resulting in light not properly focusing on the retina. Located near the optic nerve, the retina converts light into information that is then sent to the brain, where it’s then turned into the images we see. Astigmatism affects the quality of your vision by preventing light from properly focusing on the retina.
The cornea is usually round like a basketball, but astigmatism causes it to become more football-shaped. This prevents light rays from focusing on a single point, causing your vision to be out of focus at any given distance. The end result is vision that’s blurry or distorted.
Astigmatism Over Time
Astigmatism can change over time. This is due to the fact that the curve of the lens inside the eye can change, resulting in symptoms that become more — or even less — severe as time goes on. These types of changes are most common during adulthood and can signal the growth of cataracts.
Astigmatism and Other Eye Conditions
Astigmatism rarely exists on its own and is usually combined with other vision issues — most notably hyperopia and myopia. More commonly known as farsightedness and nearsightedness, hyperopia and myopia combined with astigmatism are known as refractive errors due to their effect on the eye’s ability to “refract,” or bend, light.
What Causes Astigmatism?
Your astigmatism can have different causes, the most common being:
Astigmatism is usually the result of genetics and is congenital, or present at birth. In fact, most people have some form of astigmatism. The only difference is that it’s so benign for some people that it’s not an impediment to their everyday lives. However, those with moderate to severe astigmatism will need corrective lenses, contacts, or LASIK to see more clearly.
After genetics, the next most common cause of astigmatism is trauma. Also known as irregular astigmatism, trauma-related astigmatism is usually the result of corneal scarring from an eye injury. This type is also one of the most common forms of refractive complications in children.
While rare, astigmatism can also be the result of keratoconus. When healthy, the cornea is a clear dome on the front surface of your eye. Keratoconus causes the cornea to become thinner, bulge further outward, and take on more of a cone shape. This culminates in the blurred vision associated with astigmatism as well as sensitivity to light and glare.
Symptoms of Astigmatism
The symptoms of astigmatism can vary. As we mentioned above, many people have some form of astigmatism. The difference is that it can become severe enough for some people that it requires correction.
If you’re in this category, you may be experiencing:
- Blurry vision at any distance
- Difficulty focusing your eyesight
These symptoms don’t always mean that you have astigmatism. However, they do indicate that something isn’t right. If you’re experiencing any of these symptoms then schedule an appointment with us today. Our team will be able to determine what’s causing your problem and develop a solution that works for you.
How Is Astigmatism Diagnosed?
The best method for diagnosing astigmatism is with a comprehensive eye exam. Unlike the vision screenings you may remember from school, comprehensive eye exams take a deeper look into your eyes for vision problems that have gone undiagnosed or haven’t had time to fully develop.
Individual tests during the exam can vary. You may be tested for:
- Visual acuity
Visual acuity refers to the sharpness of your vision. This is where fractions such as 20/20 or 20/40 vision come into play. To establish visual acuity, your optometrist will have you read letters on a distance chart. The more difficulty you have reading the smaller letters, the less visual acuity you actually have.
Keratometry is used to measure the curvature of your cornea. This is important for astigmatism since it affects the cornea, causing it to become misshapen. Optometrists use light to measure the reflection of your cornea and determine its exact curvature. Not only does keratometry help establish this number, but it also helps determine how your glasses should fit.
Refraction matters since astigmatism, along with myopia and hyperopia, are considered refractive errors. Your optometrist will use special tools to establish how well your eyes are able to focus light. They will then adjust the light to establish what prescription you’ll need to get the clearest vision possible.
Other Benefits of Comprehensive Eye Exams
Comprehensive eye exams can do much more than help determine the cause of your vision problems. They can also be a window into your overall health! With these in-depth exams, your optometrist can identify the signs of serious health problems such as:
- Autoimmune disorders
Think of comprehensive eye exams as a regular part of maintaining your overall health. They’re about so much more than your vision — they’re actually an important part of preventative care.
Astigmatism occurs when the cornea isn’t shaped correctly and is often present at birth. It’s usually the result of genetics, but may also be caused by an injury or disease. Astigmatism can result in vision that’s blurry at any distance, as well as eyestrain and headaches. The best way to both diagnose and develop treatment of astigmatism is with a comprehensive eye exam.
Are you concerned that you have astigmatism? Contact us today to schedule an appointment!
Hardin Valley Eyecare & Optical has been serving Knoxville since 2009. Dr. Travis Thompson and Dr. Catherine Abbott specialize in the diagnosis and treatment of a wide array of eye diseases, conditions, and problems and are committed to improving the quality of life in the Knoxville community through enhanced vision. Located at 10904 Spring Bluff Way, you can schedule an appointment online or give us a call at (865) 888-0892.