When the cornea or lens is uneven and light rays are not evenly focused on the retina?
Astigmatism: a refractive error Show
Refraction is the process of light being bent as it passes through an object. When light rays pass through your cornea and lens, they're bent (or refracted) before reaching the retina. Once the rays strike your retina, they're converted into signals that travel through the optic nerve to your brain for decoding into the images you see. If the light rays aren't evenly focused on the retina, blurred or distorted vision results. Astigmatism is one type of refractive error, but others include myopia (nearsightedness) in which distance vision is blurred, and hyperopia (farsightedness) when near vision is blurred. In astigmatism, your vision is blurred or distorted to some degree at all distances. Many people with astigmatism don't realize that they have it because, often, the symptoms come on gradually. And children born with astigmatism often go undetected until their performance in school or sports reveals a vision problem. At any age, it is important to monitor eye health with an annual eye exam and to inform your eye doctor of any changes that you notice in your vision. Astigmatism symptoms include:
If you experience any of these symptoms, please contact your eye doctor. Types of astigmatismCorneal astigmatismIn a normal eye, the cornea is round like a baseball, and fairly symmetric, so light rays bend the same way no matter what part of the cornea they enter. With corneal astigmatism, the cornea is football-shaped, which means that light rays can bend in different directions based on where they enter the cornea, causing images to appear blurry or distorted. There are two subtypes of corneal astigmatism:Regular astigmatismRegular astigmatism is the most common type, where the front surface of the eye has an oval shape Irregular astigmatismIrregular astigmatism is caused by corneal scarring from injury or surgery or from keratoconus – a disease-causing gradual thinning of the cornea Lenticular astigmatismSometimes astigmatism is not caused by a deformed cornea but rather by a distorted lens shape that causes light rays to bend abnormally and scatter before reaching the retina. Vision correction for lenticular astigmatism usually involves prescription eyeglasses with corrective lenses that compensate for the degree of astigmatism present. Astigmatism risk factorsYour risk of developing astigmatism may be higher if you have:
How is astigmatism diagnosed?Astigmatism is diagnosed with a detailed eye examination. At AEI, we use state-of-the-art technology as well as time-proven traditional tools to assess your vision. Your eye exam can include:
Non-surgical astigmatism treatmentsBasically, the only non-surgical way to treat Astigmatism is glasses and contact lenses. Contact lenses come in two forms, rigid gas permeable and soft lens options. Rigid gas permeable (RGP) contact lensesRigid gas permeable lenses are made of a special plastic that doesn't mold to your eye but rather provides a corrective lens through which light rays are bent correctly as they enter your eye. Unfortunately, due to their greater stiffness and thickness than soft lenses, some people can have difficulty getting used to RGP lenses. Toric soft lensesToric soft lenses are by far the most popular contact lens solution for astigmatism. They are formed to adjust to the shape of your eye and provide a balanced and clear vision of the various prescription zones within your eye. At AEI, we offer several toric soft lens options. Surgical astigmatism treatmentsRefractive surgeryRefractive Surgery is any surgery designed to improve your ability to focus light correctly on the retina, decreasing your dependence on glasses or contact lenses. This can take the form of laser procedures or artificial lens implantation. PRK / LASIK for astigmatismTraditionally, refractive laser surgery has been done using LASIK (laser-assisted in situ keratomileuses) for mild astigmatism or PRK (photorefractive keratectomy) for more severe astigmatism. At AEI, we offer EagleVIsion, a step beyond iDesign and Contoura Vision. Utilizing the latest LASIK technology, EagleVIsion takes a detailed map of your entire eye (cornea and additional layers) to customize your laser treatment, frequently providing better vision than you ever had with glasses or contacts. In fact, on average, EagleVIsion surpasses the best eyeglasses prescription. Learn more about LASIK surgery and AEI's EagleVision™ Lens Implantation (IOL)This surgery places a permanent prescription optical lens (IOL) inside your eye in front of your natural lens in order to correct your astigmatism. This is an option for folks with severe astigmatism who wish to be free of glasses or contact lenses and who have been told that they are not good candidates for LASIK surgery. Toric intraocular lenses (IOLs for short) have different powers in different zones of the lens that enable them to correct the asymmetric power in an astigmatic eye. If you need cataract surgery and have astigmatism, you have the option of replacing your natural lens with a toric IOL that will correct your astigmatism. Learn more about IOLs Limbal Relaxing Incisions (LRI)Limbal Relaxing Incisions are partial thickness incisions made at the outer edge of an astigmatic cornea in order to flatten its steep curvature into a rounder shape. This yields clearer vision and reduces or even eliminates the need for distance glasses. LRI is sometimes performed on folks with mild to moderate astigmatism during surgery for cataracts or implantation of intraocular lenses. At AEI, we perform this procedure using a Femtosecond laser to ensure that the relaxing incisions have the precise depth and length needed to safely correct your astigmatism. What surgical astigmatism correction is best for me?The selection of the surgical approach depends on a number of variables, such as the health of your eye, your prescription, eye shape, lifestyle, and preferences. All of the above procedures are safe and achieve clear vision for many of our patients. There are no “one size fits all” options at AEI. It depends upon your eyes, your lifestyle, and your goals. And if we believe a surgical option is not the best approach for you, we will tell you. That’s what we would want a surgeon to tell us before we undergo any procedure. And treating our patients the way we would want to be treated is one of the core tenets of our practice. Period. The AEI care differenceAssil Eye Institute’s dedication to providing the best eye care available is what motivates us to strive for the highest standards of excellence when it comes to your eye health. AEI utilizes the most advanced surgical techniques and technology available today to offer our patients the best possible vision outcomes in the safest manner. What happens when the cornea is uneven?As the cornea changes shape from a ball to a cone, the smooth surface becomes wavy. This is called irregular astigmatism. As the front expands, your vision becomes more nearsighted. That means you can see objects clearly only when they're up close.
What condition occurs when the eye does not focus light evenly?Astigmatism is caused when the eye's cornea or lens is shaped irregularly. The eye cannot focus light evenly onto the retina, resulting in focus problems and images that appear blurry or “stretched.” Astigmatism can be corrected with glasses, contacts or with refractive surgery.
What is an uneven curvature of the cornea?Astigmatism is an irregularly shaped cornea or lens that prevents light from focusing properly on the retina, the light-sensitive surface at the back of the eye. The surface of the cornea is shaped more like a football instead of round like a basketball and the eye is unable to focus light rays to a single point.
What is do you call the result of an uneven curvature of the lens or cornea prevents some light rays from being sharply focused on the retina?Astigmatism (uh-STIG-muh-tiz-um) is a common and generally treatable imperfection in the curvature of the eye that causes blurred distance and near vision. Astigmatism occurs when either the front surface of the eye (cornea) or the lens inside the eye has mismatched curves.
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