Is Laser Eye Surgery Safe?

While laser eye surgery is generally safe, it is important to be aware of potential risks and complications. At Blue Fin Vision®, we ensure you are fully informed and understand these potential issues before proceeding with any treatment. The likelihood of some events is approximate, based on available data.

• 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 (Corneal Weakening/Bulging): In very rare cases (estimated on the order of 0.05% of cases, i.e. about 1 in 2,000), the cornea can become structurally weakened after laser surgery and begin to bulge forward. This condition, called corneal ectasia, can cause worsening vision (similar to a condition called keratoconus). 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. 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.
• Flap Complications (LASIK only): LASIK involves creating a corneal flap. Flap complications are uncommon (overall well under 1% of cases), but they can occur. These include a flap that is cut imperfectly (too short, irregular), a buttonhole or small tear in the flap, or a free cap (a flap that detaches completely). During surgery, 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) for safety. After surgery, the flap can also be dislodged or shifted if the eye is rubbed or injured before it heals. This could result in wrinkles in the flap or debris trapped under the flap. 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 (for example, a flap that is irreparably damaged or infected). If a flap had to be removed, the eye would essentially heal like a PRK case – with the surface growing back over the next few days – and vision recovery would be slower, and there may be more scarring. The incidence of an extreme flap complication is exceedingly low (less than 0.1%).
• Incomplete Lenticule Extraction (SMILE only): In the SMILE procedure, a small disc of tissue (lenticule) is created in the cornea and then removed through a tiny incision. In a small percentage of cases (approximately 1% or less), the lenticule may be difficult to extract or may not come out in one piece. This is referred to as an incomplete lenticule extraction and 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.
• Epithelial Ingrowth (LASIK only): Epithelial ingrowth is when surface skin cells (epithelial cells) grow underneath the LASIK flap. This complication is uncommon, occurring in roughly 1% or fewer of first-time LASIK surgeries. (The risk can be higher if a LASIK flap is lifted for a second time during an enhancement surgery.) In most cases, small areas of epithelial ingrowth are minor and do not affect vision, and they can simply be observed over time. However, if a significant number of cells grow under the flap, they can cause visual disturbances or flap problems. Treatment involves lifting the flap and carefully removing the invading cells, then placing the flap back down. This additional procedure would be done if the ingrowth is visually significant or progressive. 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.
• Diffuse Lamellar Keratitis (DLK – LASIK only): DLK, also known as “sand 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 and is thought to be a reaction to substances or debris that get under the flap or to surgical trauma. If DLK occurs, you might not feel it (it’s 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 recognized early and treated appropriately, DLK typically resolves without any lasting effect on vision.
• Over-correction or Under-correction (Residual Refractive Error): The laser treatment is calibrated to correct your prescription, but individual healing responses vary. There is a chance that after the procedure your vision might still not be fully clear without glasses because a small amount of your prescription remains (under-correction) or because it swung past the target (over-correction). For example, a myopic (short-sighted) patient might still be a bit short-sighted after surgery or might end up slightly farsighted if over-corrected. If the residual prescription is significant for you, you might need to wear glasses or contacts for certain tasks (or even consider an enhancement surgery, see below). 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 and to ensure it is safe to re-treat). 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. As with any surgery, enhancements carry their own risks (though generally smaller due to the smaller treatment). There is also a limit to how many enhancements can be safely done. Some patients, due to individual healing or anatomy, may not be candidates for enhancement even if some prescription remains.
• Visual Disturbances (Glare, Halos, Starbursts): It is very common to experience visual side effects such as glare, halos around lights, and starburst effects in the period immediately following laser vision correction. Nearly every patient will notice some degree of these, especially at night, in the first days and weeks after surgery. For most patients, these phenomena improve over time (over 3 to 6 months) as the eyes heal and the brain adapts. However, a certain small percentage of patients may continue to experience night vision disturbances long-term. If you had 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/halo is mild, and patients find it manageable or adapt to it. It’s important to note that even prior to surgery, many people with glasses or contacts experience some halos or glare; after surgery it might be more noticeable because there is no lens to correct it. Severe, debilitating night glare that significantly affects activities like night driving is quite rare after laser vision correction (a few per hundred or less). If such symptoms are troubling, treatments such as specialized eye drops at night, wearing antireflective coated glasses at night, or in some cases a laser re-treatment (for instance, a wavefront-guided laser touch-up) could be considered.
• Dry Eye: Temporary dry eye symptoms are very common after laser vision correction, particularly after LASIK. Because creating a LASIK flap cuts some corneal nerves (which are responsible for tear production feedback), nearly all LASIK patients experience increased dryness in the weeks following surgery. PRK and SMILE can also cause dryness, but some studies suggest the effect may be slightly less than LASIK’s in terms of nerve impact (especially for SMILE, where fewer nerves might be disturbed). You will be provided with lubricating eye drops to use frequently after surgery to keep your eyes moist and comfortable. In most patients, the dryness gradually improves and returns to their presurgery baseline over a few weeks to months as the corneal nerves regenerate. However, in a small percentage of patients, dry eye symptoms can persist long-term. For example, approximately 5-10% of patients may continue to need regular artificial tears beyond 6 months after LASIK. Patients who had dry eyes before surgery, those with certain prescriptions, or those who are in environments that promote dryness (computer work, air-conditioned offices, etc.) may be more prone to this. 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. It’s important to manage dry eyes, as significant dryness can cause discomfort and also affect the clarity of your vision.

Other rare complications include corneal haze or scarring (most typically after PRK, especially if one’s healing response is aggressive – modern techniques and medications like Mitomycin-C greatly reduce this risk), transient increases in eye pressure (from steroid drops used after surgery, which is why we check your eye pressure at followups), inflammation inside the eye (uveitis, very rare), or reactivation of a 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). It is impossible to list every complication which could arise from laser vision correction surgery. The above-listed complications cover most reported issues.

Neither LASIK, PRK, nor SMILE surgery is 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 crosslinking for ectasia, as mentioned, or corneal transplant in very severe cases of scarring). Mr Hove and the medical team will do everything reasonably possible to minimise risks and to manage any complications should they occur.