Astigmatism is a common vision condition impacting millions globally, characterized by an imperfection in the eye’s curvature that leads to blurred vision. Modern laser eye surgery offers a popular and effective method for correcting various refractive errors, including astigmatism. This advanced procedure aims to reshape the eye’s surface, thereby improving how light focuses on the retina and enhancing visual clarity.
Understanding Astigmatism
Astigmatism arises when the eye’s cornea, the clear front surface, or sometimes the lens, possesses mismatched curves. Instead of a perfectly round shape, the surface is irregularly curved, often resembling a football. This irregular shape causes light to bend unevenly, preventing it from focusing properly on the retina. As a result, individuals experience blurred or distorted vision at all distances. Common symptoms include blurry vision, eyestrain, discomfort, headaches, difficulty with night vision, glare or halos around lights, or needing to squint.
How Laser Eye Surgery Corrects Astigmatism
Laser eye surgery, a form of refractive surgery, addresses astigmatism by precisely reshaping the cornea to correct its irregular curvature. An excimer laser is used to remove microscopic tissue from the anterior corneal stroma, making the cornea more spherical and enabling light to focus evenly on the retina. This precise alteration improves how the eye processes light signals, leading to clearer vision.
LASIK (Laser-Assisted In Situ Keratomileusis) is a common type of laser eye surgery for astigmatism, which is widely performed. During a LASIK procedure, a thin, hinged flap is created on the corneal surface using either a microkeratome or a femtosecond laser. This flap is lifted, allowing the excimer laser to reshape the underlying corneal tissue. After the reshaping is complete, the flap is carefully repositioned, where it adheres without stitches and facilitates quicker healing.
Another effective procedure is PRK (Photorefractive Keratectomy), which differs from LASIK by not creating a flap. In PRK, the thin outer layer of the cornea, known as the epithelium, is removed using an alcohol solution or mechanical methods. The excimer laser then directly reshapes the exposed corneal surface. A protective bandage contact lens is placed on the eye afterward to aid in healing as the epithelium regenerates over several days.
SMILE (Small Incision Lenticule Extraction) is a minimally invasive procedure also used for astigmatism correction, often in conjunction with nearsightedness. This technique utilizes a femtosecond laser to create a small, disc-shaped piece of corneal tissue, called a lenticule, within the cornea. The lenticule is then extracted through a tiny incision, reshaping the cornea and correcting the vision. SMILE is noted for preserving more corneal structure compared to LASIK, potentially leading to faster healing and a reduced risk of dry eye.
Eligibility and Considerations for Surgery
Determining suitability for laser eye surgery to correct astigmatism involves a thorough evaluation of several factors. Candidates need to be at least 18 years old, though a stable vision prescription, meaning no significant changes for at least 12 months, is required to ensure long-term results.
Sufficient corneal thickness is also an important criterion, as the procedure involves removing or reshaping corneal tissue. A comprehensive eye examination assesses the overall health of the eyes, looking for any existing conditions that might affect the outcome. Conditions that may disqualify a candidate include:
Severe dry eyes
Certain autoimmune diseases like rheumatoid arthritis or lupus
Uncontrolled diabetes
Glaucoma
Cataracts
Keratoconus, a progressive thinning of the cornea, is also a disqualifying factor due to the risk of further weakening the cornea. Pregnant or breastfeeding individuals are typically advised to postpone surgery due to hormonal fluctuations that can temporarily affect vision.
What to Expect During and After Correction
The laser eye surgery procedure for astigmatism is generally quick, often taking less than 30 minutes for both eyes, with the actual laser application lasting only seconds. Patients remain awake during the procedure, but numbing eye drops are administered to ensure comfort and prevent pain. A mild sedative may also be offered to help patients relax. Patients are asked to focus on a target light, and advanced eye-tracking systems ensure the laser remains precise even if the eye moves slightly.
Immediately after the procedure, vision may appear blurry or hazy, and some temporary discomfort or mild irritation, such as a gritty sensation, is common. Protective eyewear is usually provided to shield the eyes from bright light and debris. Vision improves significantly within the first 24 hours, allowing many patients to resume daily activities. Full visual stabilization can take several weeks to months, with complete healing extending up to six months.
Temporary side effects can include dry eyes, light sensitivity, glare, or halos around lights, especially at night. These symptoms generally resolve within a few weeks to months, though some patients may experience them for longer. Astigmatism correction has high success rates, with many patients achieving 20/20 vision or better, significantly reducing or eliminating their reliance on glasses or contact lenses. Regular follow-up appointments with the ophthalmologist are scheduled to monitor healing and address any concerns.