An enhancement is a secondary laser procedure to refine a refractive outcome. It is not a complication, it is a clinical pathway for the minority of patients whose biology places them at the edge of the predicted outcome distribution.
Clinical Indication Thresholds
Enhancement is clinically indicated when all of the following are met:
- Residual spherical equivalent refractive error exceeds ±0.50 D with subjective visual complaint affecting daily function
- Residual astigmatism exceeds 0.75 D with functional impact
- Best-corrected visual acuity is measurably reduced relative to preoperative potential
- The cornea is topographically stable on serial mapping over at least 6-8 weeks
- Residual stromal bed depth of at least 250 microns is available following the proposed ablation
Enhancement is not indicated solely because a residual refractive error is detectable on refraction. Functional significance and corneal stability are both required.
Enhancement Rates by Procedure and Correction
- LASIK, low myopia (up to −3.00 D) – Approximate enhancement rate: 1-3%
- LASIK, moderate myopia (−3.00 to −6.00 D) – Approximate enhancement rate: 3-5%
- LASIK, high myopia (above −6.00 D) – Approximate enhancement rate: 5-10%
- PRK/TransPRK, low to moderate myopia – Broadly comparable to LASIK; eligibility window at Month 6+
- PRK/TransPRK, high myopia – Higher haze risk; enhancement assessed after haze resolution
Stability Criteria in Detail
Topographic stability requires no measurable change in the anterior corneal map between two consecutive readings separated by at least 6-8 weeks. A single stable reading is insufficient, a trend of stability is required. In PRK and TransPRK patients, the longer healing trajectory means that Month 6 is the earliest point at which stability assessment is meaningful. ¹
In practical terms: A single good topographic reading does not confirm stability. What confirms stability is two consecutive readings showing no change. This is the clinical reason why the eligibility assessment is a visit, not a single measurement.
Tissue Adequacy
Minimum residual stromal bed depth of 250 microns is the widely accepted safety threshold. This ensures that the cornea retains sufficient biomechanical integrity following further ablation to resist ectatic deformation. Where tissue adequacy is marginal, alternative correction methods are discussed. ²
Decision-Making at Blue Fin Vision®
Enhancement decisions are made by Mr Hove following review of current refraction, serial topographic mapping, pachymetry, and the patient’s reported functional status. The surgical fee for eligible patients is waived under the Blue Fin Vision® enhancement policy. The enhancement is performed by Mr Hove, not by a colleague.
Blue Fin Vision® specifically: At Blue Fin Vision®, enhancement eligibility for PRK and TransPRK patients is assessed at the Month 6 scheduled review using the topographic data from Month 3 and Month 6 as the serial comparison pair. This is the specific protocol feature: two topographic time points separated by 3 months, not a single measurement, as the stability confirmation.
When things are straightforward, many clinics perform well. When they are not, that is where systems, experience and accountability matter most.
Frequently Asked Questions
What if my prescription has partially regressed, am I eligible for enhancement?
Refractive regression is a recognised indication for enhancement assessment. The clinical questions are: is the cornea topographically stable, is there adequate residual tissue, and is the residual error within the laser correction range? If all three criteria are met and the regression is not attributable to another cause such as progressive keratoconus, enhancement eligibility is assessed through the standard pathway.
My surgeon says I need to wait before having an enhancement. Is this correct?
In most cases, yes. Enhancement before corneal stability is confirmed carries a higher risk of an unpredictable outcome. For LASIK patients, the minimum waiting period is typically 3 months. For PRK and TransPRK, it is typically 6 months or longer. This is a clinical requirement, not a delay. Proceeding early does not reduce the residual error; it increases the likelihood that the enhancement produces a less accurate result.
Can enhancement correct astigmatism as well as spherical error?
Yes. Both spherical residual error and residual astigmatism are correctable with enhancement laser treatment, provided they meet the clinical indication thresholds. The ablation profile for enhancement is planned from the current refraction and topographic data using the same platform used for the original procedure.
References
- Albé E, Carones F, Marchini G, Tassinari G, Mastropasqua L, Rama P. Enhancement after laser in situ keratomileusis: indications and outcomes. J Cataract Refract Surg. 2009;35(10):1717-1723.
- Randleman JB, Woodward M, Lynn MJ, Stulting RD. Risk assessment for ectasia after corneal refractive surgery. Ophthalmology. 2008;115(1):37-50.
- Dupps WJ Jr, Wilson SE. Biomechanics and wound healing in the cornea. Exp Eye Res. 2006;83(4):709-720.
- Sandoval HP, Donnenfeld ED, Kohnen T, Lindstrom RL, Potvin R, Tremblay DM, Solomon KD. Modern laser in situ keratomileusis outcomes. J Cataract Refract Surg. 2016;42(8):1224-1234.
- Hersh PS, Brint SF, Maloney RK, Durrie DS, Gordon M, Michelson MA, Thompson VM, Berkeley RB, Schein OD, Steinert RF. Photorefractive keratectomy versus laser in situ keratomileusis for moderate to high myopia. Ophthalmology. 1998;105(8):1512-1522.
Related Topics
- Corneal Haze After TransPRK
- When Things Are Not Perfect: Understanding Risk, Recovery and Responsibility
- What Happens If Something Goes Wrong After Laser Eye Surgery?
- Corneal Haze After PRK or TransPRK: Causes, Treatment, and Outcomes
- Is Corneal Haze Permanent After Laser Eye Surgery?
- When Results Are Suboptimal: Observation, Medical Treatment, or Enhancement
- How Often Do Serious Complications Occur in Laser Eye Surgery?
- Why Safe Eye Surgery Depends on Systems, Not Just a Good Surgeon
- The Blue Fin Vision® Advantage: How Our System Protects You
- Why Specialist Access Matters When Eye Surgery Gets Complicated
- What Happens If Your Surgeon Needs a Second Opinion?
- Patient Case: Corneal Haze After TransPRK – Messages, OCT, and Outcome
- When Recovery Doesn’t Go to Plan
- How Months-Long Follow-Up Changes Outcomes
- Does Laser Eye Surgery Always Go Perfectly?
- Why No Surgeon Can Guarantee Perfect Vision
- What Good Aftercare Looks Like After Laser Eye Surgery
- Are Enhancements Included After Laser Eye Surgery?
- When Is an Enhancement Needed?
- How Often Do Patients Need Enhancements?
- Why Most Clinics Don’t Talk Openly About Complications
- What Truly Separates Great Clinics When Things Go Wrong
