Laser Eye Surgery Risks
Laser eye surgery is one of the most thoroughly studied elective procedures in modern medicine, with over 30 years of clinical data and millions of successful treatments worldwide. Serious complications are rare, and more than 95% of patients report satisfaction with their outcomes. At Blue Fin Vision®, consultant-led care, advanced laser platforms and rigorous UK protocols ensure the safest possible experience.
How Safe is Laser Eye Surgery?
Laser eye surgery is widely regarded as one of the safest and most effective elective surgical procedures available today. The safety of these procedures is supported by decades of clinical data and technological advancements that have significantly reduced risks.
Key safety factors include:
- Advanced technology: Modern lasers use sophisticated tracking systems to follow eye movements, ensuring accurate and targeted treatment.
- Sterile conditions: Procedures are performed in controlled environments, drastically reducing the risk of infection.
- Extensive screening: Patients undergo thorough assessments to ensure they are suitable candidates for the procedure.
At Blue Fin Vision®, all procedures are delivered within CQC-regulated facilities, with NOD-audited outcomes and RCOphth-aligned protocols. Your named consultant performs assessment, treatment and all follow-up appointments, ensuring continuity and expertise throughout your journey.
Common Side Effects After Laser Eye Surgery
Some temporary effects are expected as your eyes heal. These are normal responses to surgery and typically resolve without intervention:
- Dry eyes: The most common side effect, affecting nearly all LASIK patients in the weeks following surgery. Usually temporary and manageable with lubricating drops.
- Light sensitivity: Mild discomfort in bright conditions during the first few days.
- Blurred vision: Fluctuating clarity is normal during early healing, particularly with surface procedures.
- Halos and glare: Nearly every patient will notice some degree of halos around lights and starburst effects, especially at night, in the first days and weeks after surgery. These typically improve over 3–6 months.
- Red blotches: Subconjunctival haemorrhage (bleeding under the conjunctiva) can appear dramatic but resolves without treatment.
- Foreign body sensation: Mild grittiness or awareness of the eye during the first few days.
These side effects are part of normal healing and do not indicate a complication. Your consultant will explain what to expect and provide appropriate drops and support.
Short Term Risks and Treatable Complications
A small proportion of patients experience issues that require additional monitoring or treatment. Most are manageable and do not affect long-term outcomes.
Dry Eye Syndrome
Dry eye is the most frequently reported side effect after laser eye surgery. It occurs because the corneal nerves that stimulate tear production are temporarily disrupted during surgery. Symptoms include grittiness, burning, fluctuating vision and discomfort.
- LASIK: Dry eye is common in the first 3–6 months due to flap creation, which severs more corneal nerves. Nearly all LASIK patients experience increased dryness in the weeks following surgery.
- PRK/LASEK: Dry eye can occur but is often milder and shorter-lived than after LASIK.
- SMILE: Studies suggest the effect may be slightly less than LASIK, as fewer nerves are disturbed.
Most cases resolve within 3–6 months. Approximately 5–10% of patients may continue to need regular artificial tears beyond 6 months after LASIK. Patients who had dry eyes before surgery, or those in environments that promote dryness (computer work, air-conditioned offices), may be more prone to persistent symptoms. If dryness persists, additional treatments are available, such as prescription eye drops to increase tear production, punctal plugs (tiny plugs in tear drains to keep tears on the eye longer), or other therapies.
Visual Disturbances (Halos, Glare, Starbursts)
Visual disturbances such as halos around lights, glare, starbursts and ghost images are common in the early weeks after surgery, particularly noticeable when driving at night.
- If you have large pupils in low light or a very high prescription treated, you might be more prone to perceiving halos or starbursts after surgery.
- In the vast majority of cases, any persistent glare or halo is mild, and patients find it manageable or adapt to it.
- Severe, debilitating night glare that significantly affects activities like night driving is quite rare (a few per hundred or less).
If symptoms are troubling, treatments such as specialised eye drops at night, wearing anti-reflective coated glasses at night, or in some cases a wavefront-guided laser touch-up could be considered.
Over-Correction or Under-Correction
The laser treatment is calibrated to correct your prescription, but individual healing responses vary:
- Under-correction: A small amount of your prescription remains after surgery.
- Over-correction: The treatment swings past the target, causing the opposite refractive error. For example, a myopic (short-sighted) patient might end up slightly long-sighted.
Approximately 5% of patients (1 in 20) may choose to have an additional laser enhancement procedure to fine-tune the outcome, or may need to wear a thin pair of glasses for best results, especially if their original prescription was high or their eyes heal unpredictably.
An enhancement laser surgery, if needed, is usually performed no sooner than 3–6 months after the initial surgery to allow your vision to stabilise. The enhancement typically involves lifting the LASIK flap again (or in PRK/SMILE cases, performing a PRK) and applying a very small additional laser correction. There is a limit to how many enhancements can be safely done, and some patients may not be candidates for enhancement even if some prescription remains.
Diffuse Lamellar Keratitis (DLK) – LASIK Only
DLK, also known as “Sands of Sahara” syndrome, is an inflammatory reaction that can occur in the interface between the corneal flap and the underlying cornea, typically within the first week after LASIK surgery. It is rare, with an incidence reported around 1–2% in the early days of LASIK and much less with modern sterile techniques.
DLK is a sterile (non-infectious) inflammation thought to be a reaction to substances or debris under the flap or to surgical trauma. You might not feel it (it is often painless), but the surgeon will see white blood cells under the flap on examination.
Treatment involves intensive steroid eye drops to quiet the inflammation. In moderate to severe cases, the surgeon may lift the flap to irrigate (wash out) the interface and remove inflammatory cells. When recognised early and treated appropriately, DLK typically resolves without any lasting effect on vision.
Infection
Infection after laser eye surgery is very rare. The eye and surrounding area are thoroughly cleaned with an iodine solution before surgery, the procedure is performed in sterile conditions, and antibiotic drops are prescribed for post-operative use.
Symptoms of infection include increasing pain, redness, discharge and worsening vision. Prompt treatment with antibiotics is highly effective. Following aftercare instructions carefully and using prescribed antibiotic drops significantly reduces this risk.
Procedure-Specific Risks
Each laser eye surgery technique has unique characteristics that influence its risk profile.
LASIK-Specific Risks
LASIK involves creating a thin corneal flap using a femtosecond laser before reshaping the underlying tissue with an excimer laser. Flap-related complications are specific to this procedure:
Flap Complications (overall well under 1% of cases):
- Flap displacement: The flap can be dislodged or shifted if the eye is rubbed or injured before it heals, resulting in wrinkles in the flap or debris trapped underneath.
- Imperfect flap creation: A flap that is cut too short, irregular, has a buttonhole or small tear, or becomes a free cap (detaches completely). If a flap issue occurs, the surgeon may stop the procedure and either re-cut the flap immediately or later, or switch to an alternative approach (such as PRK).
- Flap wrinkles or striae: Fine folds in the flap that may affect vision; usually correctable by repositioning.
Most post-operative flap issues can be fixed by the surgeon relifting and repositioning the flap and smoothing out any wrinkles. Flap amputation (removal of the flap) is a very rare event and would only be considered in severe circumstances. If a flap had to be removed, the eye would essentially heal like a PRK case, with slower vision recovery and potentially more scarring. The incidence of an extreme flap complication is exceedingly low (less than 0.1%).
Epithelial Ingrowth (approximately 1% or fewer of first-time LASIK surgeries): Epithelial ingrowth is when surface skin cells grow underneath the LASIK flap. The risk can be higher if a LASIK flap is lifted for a second time during enhancement surgery. In most cases, small areas of epithelial ingrowth are minor and do not affect vision, and can simply be observed. However, if significant cells grow under the flap, they can cause visual disturbances.
Treatment involves lifting the flap and carefully removing the invading cells, then placing the flap back down. Most epithelial ingrowth cases are successfully managed and do not cause long-term issues. Rarely, if ingrowth recurs multiple times, more definitive measures (such as suturing the flap edge, or in extreme cases removing the flap) might be considered.
The Ziemer Z8 femtosecond laser used at Blue Fin Vision® creates highly precise, uniform flaps, minimising flap-related complications.
PRK and LASEK-Specific Risks
Surface ablation procedures (PRK, LASEK, No-Touch TransPRK) do not create a flap, eliminating flap-related risks. However, they have distinct considerations:
- Corneal haze: A cloudy appearance in the cornea during healing, most typically after PRK, especially if the healing response is aggressive. Modern techniques and medications like Mitomycin-C greatly reduce this risk.
- Longer discomfort period: The first 24–72 hours can be more uncomfortable than LASIK as the epithelium (surface layer) regenerates.
- Slower visual recovery: Vision typically takes 1–2 weeks to stabilise, compared to hours with LASIK.
- Higher risk of regression: Particularly in higher prescriptions.
Surface procedures preserve more corneal tissue and biomechanical strength, making them excellent choices for thin corneas, active lifestyles or patients at higher risk of eye trauma.
SMILE-Specific Risks
SMILE (Small Incision Lenticule Extraction) is a flapless procedure using a femtosecond laser to create and remove a small disc of corneal tissue (lenticule) through a tiny incision.
Incomplete Lenticule Extraction (approximately 1% or less): In a small percentage of cases, the lenticule may be difficult to extract or may not come out in one piece. This can result in blurry or unstable vision. If this occurs, the surgeon may need to convert the procedure, for example by switching to an excimer laser ablation (like PRK) to remove the remaining tissue, either immediately or at a later date once the cornea has healed. Alternatively, a second surgery might be performed to remove residual lenticule fragments.
Retreatment complexity: If enhancement is needed after SMILE, options include surface ablation (PRK), thin-flap LASIK or secondary SMILE.
Limited treatment range: SMILE is currently approved for myopia and astigmatism only; not yet available for hyperopia or presbyopia.
SMILE offers excellent biomechanical preservation and reduced dry eye compared to LASIK, making it particularly suitable for patients with dry eyes or high myopia.
PresbyMAX® and PRESBYOND®-Specific Risks
Presbyopia-correcting laser procedures create multiple focal zones or a “blend zone” to enable vision at all distances. Unique considerations include:
- Neuroadaptation challenges: The brain must learn to interpret images from eyes set to different focal points. Most patients adapt within weeks, but some find the adjustment period longer or incomplete.
- Compromised intermediate vision: Some patients notice a gap in clarity at arm’s length distances during adaptation.
- Night vision disturbances: Multifocal corneal profiles can increase halos and glare, particularly in low light.
- Reduced contrast sensitivity: Subtle reduction in image sharpness compared to single-focus correction.
- Monovision intolerance: A small percentage of patients do not adapt to having eyes set differently and may require reversal or modification.
Pre-operative contact lens trials can simulate the blended vision effect, helping identify patients unlikely to adapt before committing to surgery.
Rare But Serious Complications
Serious complications are uncommon but important to understand.
Serious Infection or Severe Corneal Damage
There is an approximate 1 in 10,000 risk of significant sight loss in the treated eye due to an infection or other severe complication (such as uncontrolled inflammation or scarring). The risk of severe vision loss in both eyes is far lower (on the order of one in 10 million).
Infections can occur if bacteria enter the eye or cornea during or after surgery. To mitigate this risk, the eye and surrounding area are thoroughly cleaned with an iodine solution before surgery, the procedure is performed in sterile conditions, and antibiotic drops are prescribed for post-operative use.
If a serious infection or complication does occur, it might lead to permanent scarring of the cornea and vision loss that is not correctable with glasses. In some cases, additional urgent treatments (such as intensive antibiotics or even a corneal transplant surgery) would be needed to try to restore vision.
Corneal Ectasia
Ectasia is a progressive weakening and bulging of the cornea, similar to keratoconus. It is the most serious long-term risk of laser eye surgery. In very rare cases (estimated at approximately 0.05% of cases, or about 1 in 2,000), the cornea can become structurally weakened after laser surgery and begin to bulge forward, causing worsening vision.
Ectasia may require specialised treatment such as corneal collagen cross-linking (a procedure to strengthen the cornea) and, in severe cases, might even require a corneal transplant.
Risk factors include thin corneas, high prescriptions and abnormal corneal topography. Thorough pre-operative screening (including mapping the cornea’s shape and thickness) is done to minimise this risk; patients with abnormal corneas are not offered LASIK or SMILE. PRK may be an alternative in some borderline cases, as surface treatments remove less structural tissue.
Despite careful screening, a tiny number of patients with initially normal exams can still develop ectasia. This complication can occur months to years after surgery.
Loss of Best-Corrected Vision
A very small number of patients lose lines of best-corrected visual acuity, meaning their vision with glasses or contacts is worse after surgery than before. This is rare with modern techniques and experienced surgeons.
Other Rare Complications
Other rare complications include:
- Transient increases in eye pressure: From steroid drops used after surgery, which is why eye pressure is checked at follow-up appointments.
- Inflammation inside the eye (uveitis): Very rare.
- Reactivation of prior dormant virus: For example, a history of cold sores or herpes in the eye, which can recur due to the stress of surgery. Also, rare.
Important Points About Laser Eye Surgery
Laser eye surgery is not reversible. Once the corneal tissue has been removed or reshaped, the change is permanent. However, if a complication does occur, there are often treatments available to manage it (for example, corneal cross-linking for ectasia, or corneal transplant in very severe cases of scarring).
It is impossible to list every complication which could arise from laser vision correction surgery. The complications listed above cover most reported issues. Mr Hove and the medical team will do everything reasonably possible to minimise risks and to manage any complications should they occur.
Who Has Higher Risk?
Certain factors increase the likelihood of complications or suboptimal outcomes:
- High prescriptions: Greater tissue removal increases regression and enhancement risk.
- Thin corneas: Less tissue available for treatment; may require surface procedures or alternative treatments.
- Large pupils: Increased risk of night vision disturbances if the optical zone is smaller than the pupil in dim light.
- Pre-existing dry eye: Higher risk of prolonged dry eye symptoms; requires optimisation before surgery.
- Abnormal corneal topography: Signs of early keratoconus or irregular astigmatism may contraindicate treatment or require alternative approaches.
- Autoimmune conditions: May affect healing and increase complication risk.
- Younger age (under 21): Prescriptions may not be stable, increasing regression risk.
- Unrealistic expectations: Patients expecting perfect vision in all conditions may be disappointed.
Comprehensive pre-operative assessment at Blue Fin Vision® identifies these factors, allowing informed discussion and appropriate treatment planning.
Red Flag Symptoms to Act On
Understanding which symptoms require urgent attention is essential for safe recovery.
Seek immediate eye care if you experience:
- Sudden, severe pain that worsens rather than improves
- Significant reduction in vision after initial improvement
- Increasing redness with discharge, especially if yellow or green
- Sensitivity to light with worsening vision
- Floaters or flashes of light appearing suddenly
- A dark shadow or curtain across your vision
Mild discomfort, grittiness, light sensitivity and fluctuating vision in the first few days are normal. If any symptoms concern you, contact Blue Fin Vision® for advice. Early review allows prompt treatment if needed.
Blue Fin Vision® Safety Standards
At Blue Fin Vision®, patient safety is paramount. Our protocols include:
- Comprehensive pre-operative assessment: Corneal topography, tomography, pachymetry, dry eye evaluation and detailed ocular health examination.
- Rigorous patient selection: Patients unsuitable for laser surgery are offered alternative treatments such as implantable contact lenses (ICL).
- Advanced laser technology: Ziemer Z8 femtosecond laser, SCHWIND AMARIS and ZEISS platforms deliver precision and safety.
- Consultant-led care: Your named surgeon performs assessment, treatment and all follow-up appointments.
- UK-regulated facilities: CQC oversight, NOD-audited outcomes and RCOphth-aligned protocols.
- Structured follow-up: Appointments to monitor healing and detect any issues early.
- 7-day cooling-off period: Per UK refractive surgery guidelines, ensuring informed consent without pressure.
Your safety and visual outcome are our absolute priority. If you have concerns about your suitability or risk profile, our consultants are here to discuss your individual circumstances and help you make an informed decision.
Book your FREE consultation today to discuss laser eye surgery and understand how treatment can be tailored to minimise risk and maximise your results.
