Small Incision Lenticule Extraction (SMILE) has emerged as a popular choice for laser vision correction, offering a minimally invasive procedure with a rapid recovery timeline. However, as with any surgery, a small percentage of patients might require an additional procedure to achieve their desired vision correction, known as an enhancement.
This article delves into the details of SMILE enhancements, providing insightful information for those considering this procedure.
Understanding Enhancement Rates
The good news: Enhancements following SMILE are relatively infrequent. Studies report varying rates ranging from 1% to 7%, with promising trends suggesting a potential decrease in recent years.
Research documented retreatment rates below 2% and 2.9%, showcasing the procedure’s high success rate and predictability.
Reasons for Enhancement
There are various reasons why an enhancement might be necessary after SMILE:
- Undercorrection:
This occurs when your vision isn’t fully corrected due to an imperfect nomogram, resulting in slight nearsightedness. This is frequently the main cause for further enhancement. - Overcorrection:
Less frequent, but possible, when your vision is corrected too sharply, leading to slight farsightedness or blurry vision at close range. - Degree of Myopia:
Higher levels of preoperative nearsightedness are associated with a slightly increased likelihood of requiring enhancement. - Patient Age:
Studies suggest that younger patients might have a slightly higher chance of needing an enhancement compared to older individuals. - Surgeon Experience:
As with any surgical procedure, the surgeon’s expertise plays a significant role in minimising the need for enhancements. - Delayed Myopic Regression:
In rare cases, your nearsightedness might return slightly over time, necessitating an enhancement to maintain clear vision. - Residual Astigmatism or Myopia:
Residual astigmatism or myopia can persist or develop over time, necessitating enhancement. - Additional Factors:
Other potential risk factors for an enhancement procedure may involve a small lenticular diameter, intraoperative suction loss, thick lenticule, thin residual stromal bed (RSB), and a high percentage tissue altered (PTA).
Navigating the Re-Correction Consultation
This is a pivotal moment in the patient’s experience and requires careful examination from both the surgeon and the patient.
Patient Considerations
- Time Since Initial Surgery:
Generally, patients must wait several months for their vision to stabilise before considering re-correction. - Realistic Expectations:
The patient must understand that re-correction is not a guaranteed fix and may not result in perfect vision. The goal is improvement. - Health Assessment:
Any changes in overall health or eye health since the initial surgery must be discussed.
Exploring Enhancement Options
If you require an enhancement after SMILE, several techniques exist, each with its unique advantages and drawbacks:
Photorefractive Keratectomy (PRK):
This method includes conducting PRK surgery on the SMILE cap with mitomycin C (MMC) along with alcohol-assisted PRK, i.e. ablating (removing) the stroma of the cornea using an excimer laser to reshape it for improved vision.
PRK is generally considered the most straightforward and safest enhancement option. However, it has a slower healing time compared to other methods, and there’s a slightly higher risk of haze formation, a temporary clouding of the cornea.
Laser-assisted in situ keratomileusis (LASIK):
Consists of three types:
- Thin Flap LASIK:
This method entails creating a thin flap in the SMILE cap. By default, the SMILE cap is 120 µm thick. So, it requires a LASIK flap of either 90 µm or 95 µm. This leaves a narrow margin of about 25 to 30 µm between the cap and flap cut, posing challenges for some surgeons. - Thick Flap LASIK:
In this approach, rather than cutting a flap within the cap, the cap is included in the stroma beneath it. Creating a LASIK flap deeper than 120 µm bypasses the underlying stroma, with the lenticule manipulation occurring at this level. However, this method necessitates a significant residual stromal bed. - Cap to LASIK Flap Conversion/ CIRCLE Technique:
This intricate procedure involves a side cutting and opening up the original 120-µm SMILE cap and converting that into a larger-diameter full flap of LASIK. Utilising Visumax 500, the CIRCLE technique compromises some biomechanical advantages of SMILE, heightening the risk of iatrogenic ectasia and potential flap complications. - Re-SMILE (Second Lenticule):
This emerging technique involves creating a second, smaller lenticule beneath the original SMILE cut to fine-tune the vision correction. While still under investigation, Re-SMILE holds promise as it potentially preserves the biomechanical strength of the cornea more effectively than other methods.
Choosing the Right Enhancement Approach
Your eye doctor will meticulously evaluate your situation and discuss the most suitable enhancement option for you. They will consider factors like the reason for enhancement, the specific characteristics of your cornea, your individual preferences, and your overall health.
Below are several important factors to keep in mind when deciding:
- PRK:
Offers simplicity and potentially reduces the risk of corneal weakening due to its robust biomechanical properties and preservation of the stromal bed. However, it comes with a longer healing period, a slightly elevated risk of haze formation, increased inflammation, apoptosis, and a higher risk of epithelial hyperplasia. - LASIK:
Provides rapid visual recovery, but comes with risks such as flap complications and potential corneal weakening from damage to Bowman’s layer and the anterior corneal cap. A study demonstrated a seven per cent weakening in corneas after LASIK enhancement procedures involving flap creation. It also eliminates the biomechanical advantages of SMILE. Additionally, some patients may not be suitable candidates for LASIK enhancement due to insufficient residual stromal depth. - CIRCLE:
Similar considerations as LASIK regarding flap complications and loss of biomechanical advantages. - Re-SMILE:
A promising technique under investigation, potentially preserving corneal strength, but may not be widely available due to its recent development.
Additional Considerations
- Cost:
While initial SMILE surgery might be more expensive than traditional LASIK, the potential need for fewer enhancements due to SMILE’s high accuracy can sometimes offset the initial cost difference. Discuss pricing with your doctor for both the initial SMILE procedure and any potential enhancement costs. - Long-Term Effects:
SMILE is a relatively new procedure, and long-term data regarding any potential long-term side effects is still being collected and analysed. While early studies haven’t shown any significant concerns, it’s crucial to acknowledge that more research is needed to fully understand the long-term implications of SMILE compared to other laser vision correction techniques like LASIK.
The Verdict on SMILE Surgery Re-Correction
SMILE offers a minimally invasive and effective option for laser vision correction with a low enhancement rate. However, it’s essential to be aware of the possibility of enhancement and understand the available options.
Discussing the potential benefits and drawbacks of both the initial SMILE procedure and any potential enhancement options with your qualified ophthalmologist is crucial to ensure an informed decision-making process. Additionally, acknowledging the ongoing research on the long-term effects of SMILE allows you to be aware of the evolving knowledge base surrounding this relatively new technology.
While the pursuit of perfect vision may be ongoing, the ability to take corrective steps with careful consideration and expert guidance can ensure that your sight, and your smile, remain bright.
