Have you ever noticed star bursting and head lights and street lights flaring at night time? You may have heard of this being attributed to “Astigmatism”. If you've ever wondered what astigmatism is, what causes it, and how it can be treated, you're in the right place. In this article, we'll delve into the world of astigmatism, shedding light on this prevalent eye condition.
In order to have clear vision, the cornea – which is the front clear surface of your eyes, should be uniformly curved, like the surface of a spherical basketball. Astigmatism however is more often due to the cornea having an ‘aspherical’ curvature, more akin to a rugby ball. This irregularity distorts the way light enters the eye, leading to blurred or distorted vision.
Astigmatism comes in two primary flavours: regular and irregular.
Regular astigmatism is the most common type, where the cornea has two different curvatures, typically at 90-degree angles – i.e. akin to an Ovoid instead of a Sphere.
Irregular astigmatism is less common and often results from eye injuries or certain eye conditions. In these cases the cornea may be more cone-shaped like in Keratoconus.
So what causes astigmatism? Genetics plays a significant role, so if you have family members with astigmatism, you're more likely to develop it. Other risk factors include eye injuries, surgery complications, and conditions like keratoconus – which may be exacerbated by eye allergies and subsequent excessive eye rubbing.
Astigmatism often quietly affects your vision and you may not even be aware of it until you see how much better your vision is when it has been corrected. Common symptoms include blurred vision, eye strain – especially on computer screens, headaches, and difficulty seeing at night – especially when looking at head lights of cars and street lights.
Fortunately, astigmatism is easily diagnosed by your optometrist during routine eye examination, at IC optometrist, we have an Autorefractor which gives a rough estimate of the corneal curvature, as well as a DNEye machine – which measures eye biometry, including a small corneal topographic map.
Astigmatism is highly treatable. The most common solutions include:
Eyeglasses: once a comprehensive eye examination and refraction has been done we will be able to correct your astigmatism much like how we correct short-sightedness and long-sightedness. Keep in mind, if you have a high degree of astigmatism, it is crucial the glasses making step is done as accurately as possible, as otherwise you may find your new glasses very uncomfortable to use. Here at IC optometrist, we use a Rodenstock DNEye scanner and Impressionist to customize your lenses, this takes the guesswork out of the measurements to give you clear and comfortable vision even with high astigmatism.
Contact Lenses: special toric contact lenses are designed to fit the eye's irregular curvature and provide clear vision. This is more challenging if your astigmatism is highly irregular as there are limitations to the range of power the contact lenses can correct your astigmatism to. These often will require appointments and trials to assess the best fit and vision for you.
Refractive Surgeries: Procedures like LASIK can reshape the cornea, reducing or eliminating astigmatism. However in cases of irregular astigmatism for example if caused by keratoconus, certain refractive surgeries may be contraindicated as they can sometimes make your astigmatism worse. You may therefore require a different kind of refractive surgery in this case.
Each option has its advantages and disadvantages, so it's crucial to discuss with your optometrist to determine the best choice for your needs.
Astigmatism may sound like a complex term, but it's a common eye condition that millions of people manage successfully every day. If you suspect you have astigmatism or are experiencing blurry vision, don't hesitate to consult an eye care specialist. Clear, crisp vision is within your reach, even if your cornea resembles a rugby ball more than a basketball.
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