If you have astigmatism along with myopia, you may wonder whether SMILE eye surgery can correct both problems at the same time. In many appropriately selected patients, it can. SMILE is designed to reshape the cornea to correct myopia and certain levels of myopic astigmatism.
However, not everyone with astigmatism is automatically a candidate. The amount and pattern of astigmatism, corneal shape, prescription stability, and overall eye health all influence whether SMILE is appropriate.
Understanding these factors can help you know what your eye specialist is looking for during the preoperative evaluation.
What Is Astigmatism?
Astigmatism occurs when the cornea or, less commonly, the natural lens inside the eye has an uneven curvature. Instead of focusing light evenly at a single point on the retina, the eye focuses light differently along different directions.
This can cause blurred or distorted vision at both near and far distances. You may also notice that straight lines appear slightly distorted or that objects lack sharpness.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
Astigmatism often occurs together with myopia. When both are present, a person may need glasses or contact lenses with both a spherical and cylindrical prescription.
Can SMILE Correct Astigmatism?
Yes. SMILE can correct myopia with certain levels of astigmatism by creating a lenticule designed to change the corneal shape in the required pattern.
The procedure is not simply removing the same amount of tissue across the entire cornea. The lenticule is designed according to the patient's refractive measurements so that the cornea is reshaped to reduce the refractive error.
Other laser systems, countries, and clinical settings may have different approved ranges. Your surgeon therefore needs to assess your prescription against the treatment parameters of the system being used.
Who May Benefit From SMILE for Astigmatism?
SMILE may be considered for adults who have myopia with suitable levels of myopic astigmatism and meet the other requirements for refractive surgery. People who may potentially benefit include those who:
- Have myopia combined with treatable levels of astigmatism
- Have a stable refractive prescription
- Have a cornea with suitable thickness and shape
- Do not have significant corneal abnormalities
- Have adequate overall eye health for refractive surgery
- Understand that the procedure may not completely eliminate every refractive error
- Want to reduce their dependence on glasses or contact lenses
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
How Much Astigmatism Can SMILE Treat?
The answer depends on the specific laser platform and regulatory approval. Clinical research has also investigated SMILE for higher levels of astigmatism than some approved treatment ranges. Studies and meta-analyses have found that SMILE can produce useful visual and refractive outcomes in selected patients with low, moderate, and higher astigmatism.
However, research findings should not be interpreted as an indication that every patient with high astigmatism can undergo SMILE. The approved range and individual suitability still need to be considered.
What Tests Are Done Before SMILE for Astigmatism?
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
A comprehensive assessment may include several measurements rather than relying only on your glasses prescription.
Refraction
Your spherical and cylindrical prescription is measured carefully to determine the amount and axis of refractive error.
Corneal topography and tomography
These tests evaluate the shape, curvature, thickness distribution, and structural characteristics of the cornea.
Corneal thickness measurement
The surgeon needs to know whether there is sufficient corneal tissue for the planned correction while maintaining appropriate structural integrity.
Ocular surface assessment
Dry eye and other ocular-surface problems can affect both comfort and the quality of preoperative measurements. Significant problems may need to be addressed before surgery.
Comprehensive eye examination
The overall health of the eye is assessed to identify conditions that could affect the safety or outcome of refractive surgery.
Can SMILE Correct High Astigmatism?
SMILE has been studied for higher levels of astigmatism, and research suggests that it can provide good visual outcomes in selected patients.
At the same time, higher astigmatism may make precise correction more challenging. Some studies have reported a greater tendency toward residual or undercorrected astigmatism after SMILE compared with certain other refractive techniques.
If your cylindrical prescription is above the approved range for the available SMILE system, your surgeon may discuss other options rather than performing treatment outside the established indication.
Can Astigmatism Remain After SMILE?
Yes. Although the goal of SMILE is to reduce the targeted refractive error, some residual astigmatism can remain after surgery.
The amount varies between individuals and may be influenced by the original prescription, corneal characteristics, treatment planning, and individual healing response.
Having a small amount of residual refractive error does not necessarily mean that the procedure has failed. Your postoperative refraction and visual acuity are considered together when evaluating the result.
SMILE for Astigmatism vs Wearing Glasses or Contact Lenses
Glasses and contact lenses remain effective ways to correct astigmatism without permanently changing the cornea. SMILE is different because it is a surgical procedure intended to reduce the underlying refractive error.
The potential benefit is a reduced dependence on corrective lenses, but surgery also involves risks and eligibility requirements that do not apply in the same way to glasses.
The choice therefore depends on your goals, eye health, prescription, tolerance of corrective lenses, and willingness to undergo refractive surgery.
*AI-generated image - for illustration only. Clinical accuracy is not guaranteed.
The Bottom Line
SMILE can benefit selected patients who have myopia with treatable astigmatism. The procedure can address both components of the refractive error, potentially reducing dependence on glasses or contact lenses.
However, the amount and pattern of astigmatism matter. The approved treatment range varies between systems, while clinical research has also investigated higher levels of astigmatism in carefully selected patients. Corneal thickness, corneal shape, prescription stability, ocular-surface health, and overall eye health must all be assessed before surgery.
For someone considering SMILE for astigmatism, the most important question is therefore not simply whether the procedure can correct a particular cylinder prescription. It is whether the specific prescription and corneal characteristics make the procedure appropriate and predictable for that individual.
