Did you know astigmatism occurs in about 1 in 3 people in the United States? Statistics from the American Academy of Ophthalmology revealed that more than 150 million Americans use corrective lenses to offset refractive errors, which amounts to more than $15 billion each year on eyewear.
Clearly, countless people have astigmatism to some degree (with many being unaware). This article answers some of the most common questions about astigmatism that patients ask our eye doctors in Sun City, Arizona.
What is astigmatism?
Astigmatism is a vision condition (not a disease) that a blurred eyesight characterizes. It occurs when the cornea (the transparent front layer of the eye) has an imperfect round shape. Picture this: Instead of being round like a basketball, the cornea resembles the shape of a football. This refractive error prevents light rays from meeting on a common focal point, causing vision distortion to an extent.
In addition to an irregularly shaped cornea, the shape of the lens inside the eye can also cause astigmatism. Lenticular astigmatism is the term for this condition.
What causes astigmatism?
The causes of astigmatism are not 100 percent understood. However, injury to the eye, post-cataract surgery, scarring or thinning of the cornea, and genetics are significant risk factors for astigmatism. It is often present at birth, although it may develop later in life.
Can astigmatism occur in combination with another vision problem?
In many cases, other refractive errors like nearsightedness or farsightedness accompany astigmatism. Allow us to explain the difference between the two:
- Nearsightedness (myopia). This condition occurs when the cornea is too curved or when the eye is longer than average. Instead of light focusing precisely on the retina, it focuses in front of the retina. As a result, distant objects appear blurry.
- Farsightedness (hyperopia). The cornea being curved too little or the eye being shorter than usual distinguishes hyperopia from myopia. This vision problem has the opposite effect of nearsightedness. Because the light never comes to a focus on the back of the eye in a relaxed state, nearby objects appear blurry.
What are the signs of astigmatism?
The common symptoms of astigmatism include:
- Blurred or distorted vision
- Frequent eye irritation
- Difficulty seeing at night
Some signs and symptoms of astigmatism may be because of another vision or health concern. Schedule an eye exam in Phoenix, AZ to receive an accurate diagnosis.
What happens during an eye exam for astigmatism?
Optometrists and ophthalmologists are responsible for diagnosing vision problems and eye diseases through a comprehensive eye examination. Specifically, these eye doctor may order the following tests to diagnose astigmatism:
- Visual acuity assessment test. This test involves reading letters from a standardized chart at a specific distance. Your doctor will evaluate your vision based on the smallest letters you can read.
- Refraction test. In this test, an optical refractor assists your doctor in examining your eyesight. The machine comprises multiple corrective lenses of varying strengths. Similar to a visual acuity assessment test, a refraction test requires you to read a standardized chart. The difference, however, is that you will be looking through lenses on the optical refractor. The machine allows your optometrist or ophthalmologist to conclude the most appropriate lens for correcting your eyesight.
- Keratometry. A keratometer, also recognized as an ophthalmometer, is a diagnostic instrument for measuring the curvature of the cornea. Keratometry plays an important role in assessing the breadth and axis of astigmatism.
In several cases, astigmatism improves over time. Regular eye exams with your optometrist in Maricopa County, AZ will ensure you have the proper prescription to maintain good vision.
Are there non-invasive ways to correct astigmatism?
The goal of astigmatism correction is to improve vision clarity and eye comfort. Prescription glasses and contact lenses are examples of corrective lenses, which address astigmatism by counteracting the irregular curvatures of the cornea and lens.
Read our article What’s Best for You: Eyeglasses vs. Contact Lenses to determine which of the two is more suited for your lifestyle.
How safe are contact lenses for astigmatism?
Despite the skepticism of traditionalists, multiple contact lens products in the market are specifically designed to correct astigmatism.
The main types of contact lenses for astigmatism are:
- Soft toric contact lenses. Made from a conventional hydrogel material or a breathable silicone hydrogel, soft toric lenses “have different powers in different meridians of the lens to correct the varying amount of nearsightedness or farsightedness in different meridians of the eye that characterizes astigmatism,” according to All About Vision. What’s more, toric lenses rotate to the proper orientation on the cornea, allowing the meridians of the eye to align with the power meridians of the lens for sharper vision.
- Gas permeable contact lenses. Another popular contact lens for astigmatism correction is gas permeable contact lenses. Because these rigid lenses maintain their shape regardless of your eyes’ natural shape, they compensate for astigmatism. These contacts typically provide clearer vision, but getting used to them might take longer due to their rigid nature and thicker profile.
- Hybrid contact lenses. For patients who need contacts for astigmatism, hybrid contact lenses are the most desirable choice. These innovative lenses have a central zone made from gas permeable lens material, and a fitting zone made from a silicone hydrogel material. Hybrid contacts provide the best of both worlds for astigmatism patients — the wearing comfort of toric soft lenses and clear vision of gas permeable lenses.
Is surgery for astigmatism a treatment option?
An eye doctor may recommend refractive surgery in severe cases. The procedure, which can permanently correct astigmatism, entails using lasers or small knives to alter the shape of your cornea.
The three common surgeries for astigmatism are:
- Laser in situ keratomileusis (LASIK)
- Photorefractive keratectomy (PRK)
- Radial keratotomy (RK)
While advancements in laser technology make Lasik for astigmatism an excellent option, keep in mind that all surgeries pose some risks. Speak with our board-certified ophthalmologist about laser eye surgery to learn whether the procedure is right for you.
Call Arizona Retinal Specialists at 623-474-3937 (EYES) to make an appointment with our doctors. Remember, your best defense against a declining vision is to have regular checkups.