What is Astigmatism?
Astigmatism is a common refractive error that results in blurred or distorted vision. It happens when the cornea, the clear front surface of the eye, or the lens within the eye has an irregular shape. The cornea or lens is not perfectly round like a basketball, but rather like a football, with one meridian significantly more curved than the perpendicular one. This irregularity prevents light from properly focusing on the retina, the light-sensitive layer in the back of the eye, resulting in visual distortion at all distances.
Astigmatism can occur at birth or develop following an eye injury, disease, or surgery. It is frequently associated with other refractive errors, such as myopia (nearsightedness) or hyperopia (farsightedness). The condition’s severity varies, with mild cases causing only slight blurring and more severe cases having a significant impact on vision and quality of life. Common symptoms include eye strain, headaches, squinting, and night vision problems. Regular eye exams are essential for detecting astigmatism early on and taking appropriate corrective measures to ensure clear vision.
Traditional Astigmatism Treatments
The traditional management and treatment of astigmatism focuses on correcting the refractive error to improve vision clarity and alleviate associated symptoms. Various methods are used to accomplish this, each one tailored to the individual’s needs and the severity of the astigmatism. Here are the standard approaches.
Prescription Glasses
Prescription glasses are the most common and straightforward way to correct astigmatism. These glasses have lenses that compensate for the irregular curvature of the cornea or lens, allowing light to properly focus on the retina. The lenses are specially ground to match the degree and orientation of astigmatism, resulting in clear and comfortable vision. Glasses are especially useful for people with mild to moderate astigmatism, and they are frequently the first line of treatment recommended by eye care professionals.
Contact lenses
Contact lenses are another effective method for correcting astigmatism. Unlike glasses, which sit on the nose and change the direction of incoming light, contact lenses rest directly on the cornea, allowing for a more natural field of vision. There are several types of astigmatism-specific contact lenses:
Toric Contact Lenses
Toric contact lenses are custom-made to correct astigmatism. They have different optical powers and focal lengths along different meridians of the lens, allowing them to correct the cornea’s irregular curvature. Toric lenses are available in both soft and rigid gas-permeable (RGP) materials, allowing patients to choose their preferred material and level of comfort.
Rigid gas-permeable (RGP) lenses
RGP lenses, also known as hard contact lenses, are an additional option for astigmatism correction. These lenses retain their shape on the eye, resulting in a more stable and precise correction than soft lenses. RGP lenses can be especially effective for people with high astigmatism or who struggle to see clearly with soft toric lenses.
Refractive Surgery
For those looking for a more permanent solution, refractive surgery is an option. Surgical options aim to reshape the cornea to correct the irregular curvature that causes astigmatism. The most common surgical procedures are:
Laser Assisted In Situ Keratomileusis (LASIK)
LASIK is a popular and highly effective method of correcting astigmatism. It entails making a thin flap in the cornea and then using an excimer laser to reshape the underlying corneal tissue. The flap is then repositioned, allowing for rapid healing while minimizing discomfort. LASIK provides quick visual recovery and long-term results, making it a popular choice among many patients.
Photorefractive Keratectomy(PRK)
PRK is another laser-based procedure for correcting astigmatism. Unlike LASIK, PRK involves removing the cornea’s outer layer (epithelium) and reshaping the underlying tissue with an excimer laser. The epithelium regenerates over time, resulting in a smooth surface for vision. PRK is frequently recommended for people with thinner corneas or who aren’t good candidates for LASIK.
Astigmatic Keratotomy (AK)
Astigmatic keratotomy (AK) is a surgical procedure that involves creating precise incisions in the cornea to reduce its irregular curvature. This technique is frequently used in conjunction with other refractive surgeries or cataract surgery to achieve the best results. AK is particularly effective at correcting moderate to severe astigmatism.
Orthokeratology (O-K)
Orthokeratology (or Ortho-K) is a non-surgical treatment that entails wearing specially designed rigid contact lenses overnight. These lenses gently reshape the cornea while you sleep, giving you clear vision throughout the day without the need for glasses or contact lenses. Ortho-K is especially popular with people who have mild to moderate astigmatism and prefer a non-invasive treatment.
Cutting-Edge Astigmatism Therapies
The management and treatment of astigmatism has advanced significantly in recent years, owing to technological advancements and a better understanding of the condition. These advancements aim to provide more precise, effective, and personalized treatment options for people with astigmatism. Here, we look at some of the most recent innovations in astigmatism management and treatment:
Wavefront-guided LASIK
Wavefront-guided LASIK is a more advanced type of LASIK surgery that uses precise measurements of how light waves travel through the eye to create a map of the eye’s unique flaws. This customized approach allows for more accurate correction of astigmatism and other refractive errors, resulting in better visual outcomes and a lower risk of complications like glare and halos. Wavefront-guided LASIK can improve overall vision quality by correcting higher-order aberrations, resulting in sharper and clearer images.
Topography-guided LASIK
Topography-guided LASIK is another cutting-edge technique that uses detailed corneal topography maps to direct laser treatment. This approach focuses on correcting the specific corneal irregularities and asymmetries that cause astigmatism. Topography-guided LASIK has the potential to improve visual outcomes, especially for patients with irregular corneas or who have had previous corneal surgery. This method can provide more precise and personalized results because it tailors the treatment to each eye’s unique topography.
Small Incision Lenticule Extraction (SMILE)
Small incision lenticule extraction (SMILE) is a minimally invasive refractive surgery that is increasingly popular for correcting astigmatism. Unlike LASIK, which involves making a corneal flap, SMILE employs a femtosecond laser to create a small, lens-shaped piece of tissue (lenticule) within the cornea. The lenticule is then removed via a small incision, reshaping the cornea and correcting the refractive error. SMILE provides several benefits, including faster recovery, a lower risk of dry eye, and improved corneal structural integrity. It is especially suitable for people with high levels of astigmatism or who prefer a flapless procedure.
Custom Contact Lenses
Contact lens technology advancements have resulted in the development of customized contact lenses that provide superior comfort and visual performance for people with astigmatism. These lenses are custom-made for each patient’s specific curvature and shape, resulting in a more precise fit and improved astigmatism correction. Modern materials and designs improve oxygen permeability, which reduces the likelihood of dryness and discomfort. Customized contact lenses are available in soft and rigid gas-permeable (RGP) materials, providing flexibility based on patient preferences and visual requirements.
EDOF Intraocular Lenses (IOLs)
Individuals with astigmatism undergoing cataract surgery may benefit from extended depth of focus (EDOF) intraocular lenses (IOLs). EDOF IOLs provide a continuous range of vision from close to far, reducing the need for glasses following surgery. These lenses feature advanced optics that correct astigmatism while improving visual performance at varying distances. EDOF IOLs are especially beneficial for patients who want more visual independence and a better quality of life following cataract surgery.
Corneal Collagen Crosslinking (CXL)
Corneal collagen cross-linking (CXL) is a novel treatment option for people who have progressive astigmatism due to conditions like keratoconus. CXL involves applying riboflavin (vitamin B2) drops to the cornea, followed by exposure to ultraviolet (UV) light. This process strengthens the cornea’s collagen fibers, stabilizing its shape and preventing astigmatism from progressing further. To achieve the best results, combine CXL with other treatments, such as topography-guided PRK. This minimally invasive procedure presents a promising option for treating astigmatism in patients with corneal ectatic disorders.
Scleral Contact Lenses
Scleral contact lenses are large-diameter lenses that sit on the sclera (the white part of the eye) and cover the cornea. These lenses feature a smooth optical surface that effectively corrects irregular astigmatism and other refractive errors. Scleral lenses are especially useful for people who have severe astigmatism, keratoconus, or corneal irregularities. Scleral lenses are an excellent choice for patients who struggle with traditional contact lenses due to their larger size and unique design, which provides superior comfort, stability, and visual acuity.
