Did Eye Pressure Increase After Smile Surgery?

Explore the potential impact of SMILE surgery on eye pressure. Learn if this laser eye procedure might lead to increased intraocular pressure.

4 min readFeb 9, 2024

SMILE surgery (Small Incision Lenticule Extraction) is a contemporary vision correction procedure known for its minimal invasiveness, quick recovery times, and the potential to improve visual acuity. However, there are concerns about its potential impact on intraocular pressure (IOP). IOP is a crucial factor in eye health, with abnormal levels potentially leading to conditions like glaucoma. The question of whether SMILE surgery leads to an increase in IOP has been the subject of much debate. This article aims to delve into the existing research and offer insights into the potential relationship between SMILE surgery and elevated eye pressure.

The effect of SMILE surgery on eye pressure, or intraocular pressure (IOP), is complex and not always consistent. Here’s what we know:

Temporary Increase:

Yes, a temporary increase in eye pressure (IOP) is possible during SMILE surgery. This is typically caused by the use of the femtosecond laser to create the lenticule, the small disc of corneal tissue that is removed during the procedure.

The increase in IOP is usually transient, meaning it only lasts for a few minutes. It’s caused by a combination of factors, including:

The suction is applied to the eye to stabilize it during the laser treatment.
The release of fluid from the lenticule as it is created.
The temporary disruption of the eye’s normal drainage mechanisms.

The amount of IOP increase can vary depending on the individual patient and the specific details of the surgery. However, it’s generally not considered to be a cause for concern.

Here are some additional things to keep in mind about temporary IOP increases after SMILE surgery:

Most patients do not experience any noticeable symptoms from the IOP increase.
The increase in IOP is usually not high enough to cause any damage to the eye.
Your ophthalmologist will monitor your IOP before, during, and after surgery to ensure it stays within a safe range.

A long-term increase in eye pressure after SMILE surgery is not a typical or expected outcome. While both SMILE and other laser vision correction procedures like LASIK can cause a temporary increase in intraocular pressure (IOP) during and immediately after surgery, this usually resolves within a few days or weeks.

Here’s what we know about IOP changes after SMILE:

Transient IOP Elevation: During SMILE, the femtosecond laser creates a lenticule inside the cornea, and in some cases, temporary IOP elevation (up to 20–30 mmHg) can occur due to the suction applied to stabilize the eye. This is generally transient and doesn’t cause any long-term issues.
Long-Term Stability: Studies on the long-term effects of SMILE on IOP indicate stability or even a slight decrease in IOP over time. This is likely due to the flattening effect of the corneal reshaping performed during the surgery.
Risk Factors: Certain factors, such as pre-existing glaucoma or steroid use after surgery, might increase the risk of IOP issues after SMILE. However, even in these cases, significant or long-term increases in IOP are not common.

Long-term decrease in eye pressure after smile surgery

There’s growing evidence suggesting that SMILE surgery might actually lead to a long-term decrease in eye pressure (IOP). This is contrary to what many might expect, considering the temporary IOP increase during the procedure itself.

Here’s a breakdown of the potential long-term decrease in IOP after SMILE surgery:

Mechanism:

The decrease is thought to be linked to the reshaping of the cornea during the procedure. SMILE removes a lenticule, a disc of corneal tissue, through a tiny incision. This reshaping can:

Increase the outflow of aqueous humor, the fluid that fills the eye and helps maintain IOP.
Reduce the resistance to outflow, making it easier for aqueous humor to drain.
Decrease the production of aqueous humor in some cases.

Evidence:

Studies: Several studies have observed a decrease in IOP following SMILE surgery. One study, for example, reported an average decrease of 5 mmHg in IOP 3 months after surgery.
Comparison with other procedures: Compared to traditional LASIK surgery, which creates a larger corneal flap, SMILE has a more sustained and significant IOP-lowering effect.

Benefits:

Reduced risk of glaucoma: Lower IOP is a key factor in preventing glaucoma, a serious eye condition that can cause vision loss. Therefore, the potential IOP-lowering effect of SMILE could offer long-term benefits for some patients.
Improved overall eye health: Maintaining healthy IOP is crucial for overall eye health and can reduce the risk of other eye diseases.

Important Points:

Individual Variability: The extent of the IOP decrease can vary depending on individual factors like pre-existing eye conditions, the amount of tissue removed, and the specific technique used.
Monitoring: Regular monitoring of IOP is essential after SMILE surgery, regardless of the observed initial decrease.
Consultation: Consulting with your ophthalmologist is crucial to understanding your risk factors and potential benefits of SMILE surgery in terms of IOP management.

While the long-term IOP-lowering effect of SMILE is promising, it’s essential to remember that it’s still an emerging area of research. More studies are needed to confirm the long-term effects and establish specific guidelines for patient selection and management.