Astigmatism is a common vision condition impacting how light focuses on the retina, leading to blurred or distorted vision across all distances. This refractive error arises from an irregularly shaped cornea or lens inside the eye. Small Incision Lenticule Extraction, known as SMILE, offers a laser eye surgery to address this condition.
Basics of Astigmatism and SMILE
Astigmatism occurs when the cornea, the clear front surface of the eye, or the eye’s lens has an oblong or oval shape instead of a perfectly round one, similar to a football rather than a basketball. This irregular curvature causes light rays entering the eye to focus at multiple points instead of a single point on the retina, resulting in blurry or stretched vision. Individuals with astigmatism experience symptoms like eye strain, difficulty seeing at night, and headaches.
SMILE surgery is a minimally invasive laser procedure that corrects refractive errors, including nearsightedness (myopia) and astigmatism. Unlike procedures like LASIK, SMILE does not involve creating a large corneal flap. Instead, it reshapes the cornea by removing a small, disc-shaped piece of tissue from within its layers. This technique reduces reliance on glasses or contact lenses by improving the cornea’s ability to focus light onto the retina.
How SMILE Addresses Astigmatism
The SMILE procedure uses a femtosecond laser to precisely reshape the cornea. The laser creates a thin, lens-shaped piece of corneal tissue, known as a lenticule, within the intact layers of the cornea. This lenticule is designed to match the irregular curvature of the patient’s astigmatism, providing a customized correction.
After the lenticule is created, the same femtosecond laser makes a tiny incision on the surface of the cornea, which is typically less than 4 millimeters long. This small incision provides the surgeon with access to the pre-formed lenticule. The surgeon then extracts the lenticule through this opening, removing the precise amount of tissue needed to reshape the cornea. The removal of this lenticule permanently alters the cornea’s curvature, correcting astigmatism and allowing light to focus properly on the retina, thereby improving vision.
Who is a Candidate and Expected Results
SMILE surgery is suitable for correcting astigmatism, but specific criteria determine candidacy. Individuals should be at least 22 years old and have had a stable eye prescription for at least 12 months. The procedure is FDA-approved to treat astigmatism up to -3.00 diopters. It is also performed for nearsightedness ranging from -1.00 to -10.00 diopters.
A comprehensive eye examination is necessary to confirm suitability for SMILE, as overall eye health is important. Patients should not have existing eye diseases such as retinal problems, severe dry eyes, or corneal scars. Women who are pregnant or nursing are not recommended for the procedure. After SMILE, most patients experience vision improvement, with many achieving 20/20 or 20/40 vision or better. Studies show a high percentage of patients reach excellent visual acuity, often reducing or eliminating the need for corrective eyewear.
Preparing for and Recovering from SMILE
Before SMILE surgery, patients receive specific instructions, including discontinuing contact lens wear for a period to ensure accurate corneal measurements. On the day of the procedure, the eye is numbed with eye drops for comfort, and an eyelid holder prevents blinking. The entire laser treatment is quick, lasting less than 30 seconds per eye, and the full procedure takes about 10 to 20 minutes per eye.
Following SMILE surgery, recovery is rapid due to the minimally invasive nature of the procedure. Patients notice improved vision almost immediately, with clarity continuing to refine over the next 7 to 10 days. Mild discomfort, light sensitivity, and hazy vision are initial experiences, and lubricating eye drops are prescribed to aid healing. Most individuals can resume normal activities, including driving, within one to two days, though strenuous activities and swimming should be avoided for at least a week to prevent complications.