Astigmatism is a common eye condition that affects millions of people worldwide. Despite its prevalence, many individuals have limited knowledge about astigmatism. In this blog post, we will explore what astigmatism is, its causes, symptoms, and the various treatment options available to improve vision for those affected by this condition.
Astigmatism is a refractive error that affects the way light enters the eye, causing blurred or distorted vision. It occurs when the cornea (the clear front surface of the eye) or the lens (the structure inside the eye that focuses light) is irregularly shaped, preventing light rays from converging properly on the retina at the back of the eye. Instead of focusing on a single point, the light scatters, resulting in vision problems.
There are two primary causes of astigmatism. The first is corneal astigmatism. This is the most common form of astigmatism and occurs when the cornea has an irregular shape, similar to a football instead of a perfectly rounded basketball. This irregular curvature causes light to refract differently in different directions, leading to blurred vision. The second cause of astigmatism, lenticular astigmatism, is much less common than corneal astigmatism. Lenticular astigmatism is caused by an irregularly shaped lens inside the eye. This can occur due to factors such as eye injuries or certain medical conditions.
Astigmatism can manifest with a range of symptoms, including, blurred or distorted vision at various distances, eye strain and discomfort, headaches (especially after reading or using digital devices), difficulty seeing at night, squinting to see clearly and double vision.
Diagnosing astigmatism typically involves a comprehensive eye exam performed by an optometrist or ophthalmologist. Once diagnosed, astigmatism can be corrected through various treatment options. The most common and non-invasive way to correct astigmatism is by wearing eyeglasses with special lenses designed to compensate for the irregular shape of the eye. Another alternative treatment option are Toric contact lenses. Specifically designed for astigmatism, Toric lenses can provide clear vision without glasses. Soft, rigid gas-permeable, and hybrid lenses are available for different preferences. Another lens option for those with astigmatism are orthokeratology, or Ortho-K, lenses. This involves using specialized rigid contact lenses worn overnight to reshape the cornea temporarily, providing clearer vision during the day.
On an eyeglass or contact prescription that is given to treat astigmatism, the degree of astigmatism correction is indicated by the CYLINDER and AXIS components of the prescription. Based on whether you receive your prescription from an optometrist or an ophthalmologist, these numbers may differ. Historically, optometrists have preferred to write prescriptions with negative cylinder values, while ophthalmologists have generally preferred positive cylinder notation. The origins and reasons for this convention are hotly debated. The very first instances of cylinder being ground into eyeglasses were noted in plus form, however this convention changed in the early 1900s to the minus form. Both notations are commonly used today, and can be easily converted to the other using a simple mathematical equation. On Respectacle’s website any eyeglass prescription entered in minus cylinder notation is converted automatically to plus cylinder for the purposes of searching.
For those who want to get out of glasses, LASIK surgery can also treat astigmatism. Laser-assisted in situ keratomileusis (LASIK) is a surgical procedure that reshapes the cornea to correct astigmatism. Similar to LASIK, photorefractive keratectomy, or PRK, is a surgical procedure that reshapes the cornea. PRK may be recommended for those who are not suitable candidates for LASIK. These surgical options offer more permanent solutions, but it’s essential to consult with an eye specialist to determine eligibility.
Astigmatism is a common vision problem that can affect anyone, but with proper diagnosis and treatment, it can be effectively managed. Whether you opt for eyeglasses, contact lenses, or surgical options like LASIK, the goal is to improve your vision and enhance your overall quality of life. Regular eye exams are crucial for early detection and prompt management of astigmatism, so be sure to consult with an eye care professional if you suspect any vision issues.