Astigmatism is a common vision condition causing blurred or distorted vision. It occurs when the eye’s cornea or lens has an irregular shape, preventing light from focusing correctly on the retina. Surgical solutions aim to reshape the eye’s refractive surfaces, allowing light to focus sharply and improve vision.
Surgical Approaches for Astigmatism
Several refractive surgical options are available to correct astigmatism. Laser-Assisted In Situ Keratomileusis (LASIK) is a widely performed procedure where a thin flap is created in the cornea. An excimer laser then reshapes the underlying corneal tissue. After reshaping, the flap is repositioned, adhering naturally without stitches.
Photorefractive Keratectomy (PRK) is another laser surgery option, suitable for individuals with thinner corneas. In PRK, the outermost layer of the cornea, the epithelium, is gently removed. An excimer laser then reshapes the underlying corneal tissue, and the epithelium regenerates over time. Small Incision Lenticule Extraction (SMILE) is a minimally invasive procedure utilizing a femtosecond laser to create a small, lens-shaped piece of corneal tissue (a lenticule) inside the cornea. The surgeon removes this lenticule through a tiny incision, altering the corneal shape.
For more severe cases or older patients with cataracts, intraocular lenses (IOLs) can be an option. Toric IOLs are specialized lenses designed to correct astigmatism during cataract surgery or refractive lens exchange. These lenses are implanted into the eye to replace or augment the natural lens, providing clear focus.
How These Surgeries Correct Astigmatism
Astigmatism occurs when the cornea or lens is shaped more like a rugby ball than a perfectly round soccer ball. This irregular shape causes light to enter the eye at multiple points, preventing proper focus on the retina.
Laser procedures like LASIK, PRK, and SMILE reshape the cornea to create a more spherical surface. An excimer laser precisely removes microscopic amounts of corneal tissue in a specific pattern. This reshaping changes how light bends as it passes through the cornea, allowing it to converge at a single focal point on the retina. For instance, LASIK flattens or steepens the cornea as needed to achieve an evenly rounded surface.
Toric IOLs correct astigmatism by providing a compensatory curvature within the implanted lens itself. These lenses are carefully measured and oriented within the eye to counteract the irregular curvature of the cornea. This correction enables light to focus properly on the retina.
Candidacy and Considerations
Suitability for astigmatism surgery depends on several factors. A stable vision prescription for at least one year is required, as fluctuating vision can impact surgical results. Patients must be 18 years or older, with some clinics preferring individuals to be at least 21. Good overall eye health is important, including no active infections, severe dry eye, or serious conditions like glaucoma or cataracts.
Corneal thickness is important, as laser procedures remove corneal tissue. If corneas are too thin, LASIK may not be safe, making PRK or SMILE more suitable alternatives. Individuals with conditions like keratoconus, where the cornea thins and bulges, are not candidates for standard laser eye surgery.
Patients should have realistic expectations about the surgical outcome. While many achieve significantly improved vision, it is not always 20/20, and some may still require glasses for certain activities. Potential side effects include temporary dry eyes, glare, halos around lights, or double vision, which resolve within weeks or months. Consulting with an ophthalmologist for a comprehensive evaluation is crucial for assessing eligibility and discussing the most appropriate surgical approach.
The Surgical Experience and Recovery
Astigmatism correction surgery is straightforward and performed on an outpatient basis. Before the procedure, the eye surgeon conducts a comprehensive eye exam to measure refractive errors and map corneal shape. On the day of surgery, numbing eye drops are administered for comfort, and patients may receive relaxing medication. The procedure itself is quick, taking less than 30 minutes for both eyes.
Immediately following surgery, patients may experience visual haziness or mild irritation. Eye shields are provided to protect the eyes, especially during sleep. Prescribed eye drops aid healing and prevent infection. Most experience significant vision improvement within 24 to 48 hours, allowing a return to many daily activities.
Full vision stabilization can take several weeks to months, with some fluctuations. Dry eye symptoms, light sensitivity, and temporary halos or glare around lights are common but diminish over three to six months. Following all post-operative instructions is crucial, including avoiding activities like swimming or contact sports for a specified period, and attending all follow-up appointments to monitor healing.