Astigmatism is a common vision imperfection caused by an irregular curvature of the eye’s cornea or lens. Instead of a spherical shape, the eye’s front surface resembles a football or an egg, causing light to focus unevenly on the retina. This results in blurred or distorted vision at all distances. Laser eye surgery offers a proven solution to correct this condition.
How Laser Eye Surgery Addresses Astigmatism
Laser eye surgery corrects astigmatism by precisely reshaping the cornea, transforming its irregular curvature into a more symmetrical surface. This reshaping allows light to converge properly on the retina, thereby improving visual clarity. The excimer laser ablates microscopic amounts of corneal tissue according to the patient’s specific prescription.
Several laser procedures are employed for astigmatism correction. LASIK, or Laser-Assisted In Situ Keratomileusis, involves creating a thin, hinged flap in the cornea using a femtosecond laser. The surgeon lifts this flap to access the underlying corneal tissue, known as the stromal layer. An excimer laser then reshapes this exposed tissue to correct the astigmatism. After treatment, the corneal flap is repositioned, adhering naturally.
Photorefractive Keratectomy, or PRK, is another method that reshapes the cornea’s surface. Unlike LASIK, PRK does not involve creating a corneal flap. Instead, the outer layer of the cornea, the epithelium, is removed to expose the underlying tissue. The excimer laser then directly reshapes the corneal surface. The epithelial layer subsequently regrows over several days, protecting the treated area.
SMILE, or Small Incision Lenticule Extraction, is a newer laser eye surgery. This flapless procedure uses a femtosecond laser to create a small, disc-shaped piece of corneal tissue, called a lenticule, within the cornea. A tiny incision, typically less than 4 millimeters, is then made on the corneal surface. Through this opening, the surgeon removes the lenticule, reshaping the cornea and correcting astigmatism. SMILE’s minimally invasive nature may reduce the risk of post-operative dry eyes compared to LASIK.
Eligibility for Laser Astigmatism Correction
Determining suitability for laser eye surgery involves a thorough assessment of various factors. Candidates should be at least 18 years old, with some clinics preferring patients to be in their early twenties to ensure eye development has stabilized. A consistent eye prescription for at least one to two years before surgery is also a requirement, indicating stable vision and reducing the likelihood of future changes.
Corneal thickness is a criterion, as sufficient thickness is necessary to ensure the eye’s structural integrity after reshaping. Eye health is also important; individuals with conditions like glaucoma, cataracts, severe dry eye syndrome, or keratoconus (a progressive thinning of the cornea) may not be suitable.
Systemic health conditions also influence eligibility. Autoimmune diseases, uncontrolled diabetes, or conditions that impair healing may prevent the procedure. Pregnancy and breastfeeding are temporary contraindications due to hormonal fluctuations affecting vision stability. A comprehensive eye examination by an ophthalmologist is necessary to determine if laser astigmatism correction is a safe option.
The Surgical Process and Recovery
On the day of laser eye surgery, patients arrive at the clinic before their procedure. They are given mild oral medication to relax, and anesthetic eye drops numb the eyes completely. The laser treatment is brief, often lasting only a few minutes per eye. During the procedure, patients focus on a target light, and an eye-tracking system helps align the laser with eye movements.
Immediately following surgery, patients may experience some mild discomfort, such as a gritty sensation or light sensitivity. Vision will likely be blurry. Patients are advised to rest with their eyes closed for several hours after the procedure and wear protective eye shields, especially while sleeping, to prevent accidental rubbing.
Post-operative care involves using prescribed eye drops, which may include antibiotics to prevent infection and anti-inflammatory drops to reduce swelling. These drops are used for a specified period, usually a few weeks. Initial healing occurs rapidly, with vision improvement noticeable within the first few days. However, vision stabilization can take several weeks to a few months as the eye fully recovers and adapts to its new shape. Regular follow-up appointments with the surgeon are scheduled.
Achieving Vision Improvement
Following laser astigmatism correction, most individuals experience improvement in their uncorrected vision. Many patients achieve 20/20 or 20/40 vision, a common benchmark for driving without corrective lenses. While initial vision clarity is immediate, full stabilization of vision occurs over several weeks to a few months.
While laser surgery reduces or eliminates the need for glasses or contact lenses for most daily activities, it does not prevent age-related vision changes. For instance, individuals over 40 may still require reading glasses due to presbyopia, a natural hardening of the eye’s lens. Some individuals with specific visual demands, such as pilots or graphic designers, might occasionally opt for glasses even after surgery.
The correction achieved through laser eye surgery is generally stable over time. However, factors such as natural aging, very rare cases of regression (where the eye gradually returns to its pre-surgical state), or the onset of other eye conditions can influence long-term outcomes. Regular eye check-ups are recommended to monitor eye health and vision stability.