LASIK Eye Surgery Complications

A subconjunctival hemorrhage is a common and minor post-LASIK complication.The incidence of refractive surgery patients having unresolved complications six months after surgery has been estimated from 3% to 6%. The following are some of the more frequently reported complications of LASIK:

Dry eyes
Overcorrection or undercorrection
Visual acuity fluctuation
Halos or starbursts around light sources at night
Light sensitivity
Ghosts or double vision
Wrinkles in flap (striae)
Decentered ablation
Debris or growth under flap
Thin or buttonhole flap
Induced astigmatism
Corneal Ectasia
Epithelium erosion
Posterior vitreous detachment
Macular hole
Complications due to LASIK have been classified as those that occur due to preoperative, intraoperative, early postoperative, or late postoperative sources:

LASIK Eye Surgery - Intraoperative complications
The incidence of flap complications has been estimated to be 0.244%. Flap complications (such as displaced flaps or folds in the flaps that necessitate repositioning, diffuse lamellar keratitis, and epithelial ingrowth) are common in lamellar corneal surgeries but rarely lead to permanent visual acuity loss; the incidence of these microkeratome-related complications decreases with increased physician experience. This risk is further reduced by the use of IntraLasik and other non-microkeratome related approaches.
A slipped flap (a corneal flap that detaches from the rest of the cornea) is one of the most common complications. The chances of this are greatest immediately after surgery, so patients typically are advised to go home and sleep to let the flap heal. A faster operation may decrease the chance of this complication, as there is less time for the flap to dry.
Flap interface particles are another finding whose clinical significance is undetermined. A Finnish study found that particles of various sizes and reflectivity were clinically visible in 38.7% of eyes examined via slit lamp biomicroscopy, but apparent in 100% of eyes using confocal microscopy.

LASIK Eye Surgery - Early postoperative complications
The incidence of diffuse lamellar keratitis (DLK, also known as the Sands of Sahara syndrome, has been estimated at 2.3%. When diagnosed and appropriately treated, DLK resolves with no lasting vision limitation.
The incidence of infection responsive to treatment has been estimated at 0.4%. Infection under the corneal flap is possible. It is also possible that a patient has the genetic condition keratoconus that causes the cornea to thin after surgery. Although this condition is screened in the preoperative exam, it is possible in rare cases (about 1 in 5,000) for the condition to remain dormant until later in life (the mid-40s). If this occurs, the patient may need rigid gas permeable contact lenses, Intrastromal Corneal Ring Segments (Intacs), Corneal Collagen Crosslinking with Riboflavin or a corneal transplant.
The incidence of persistent dry eye has been estimated to be as high as 28% in Asian eyes and 5% in Caucasian eyes. Nerve fibers in the cornea are important for stimulating tear production. A year after LASIK, subbasal nerve fiber bundles remain reduced by more than half. Some patients experience reactive tearing, in part to compensate for chronic decreased basal wetting tear production.
The incidence of subconjunctival hemorrhage has been estimated at 10.5%.[14]

LASIK Eye Surgery - Late postoperative complications
The incidence of epithelial ingrowth has been estimated at 0.1%.
Glare is another commonly reported complication of those who have had LASIK.
Halos or starbursts around bright lights at night are caused by the irregularity between the lasered part and the untouched part. It is not practical to perform the surgery so that it covers the width of the pupil at full dilation at night, and the pupil may expand so that light passes through the edge of the flap into the pupil. In daytime, the pupil is smaller than the edge. Modern equipment is better suited to treat those with large pupils, and responsible physicians will check for them during examination.
Late traumatic flap dislocations have been reported 1–7 years post-LASIK.

Other Complications of LASIK Eye Surgery
Although there have been improvements in LASIK technology, a large body of conclusive evidence on the chances of long-term complications is not yet established. Also, there is a small chance of complications, such as slipped flap, corneal infection, haziness, halo, or glare some of which are irreversible because the LASIK eye surgery procedure is irreversible.

The incidence of macular hole has been estimated at 0.2 per cent to 0.3 per cent. The incidence of retinal detachment has been estimated at 0.36 per cent. The incidence of choroidal neovascularization has been estimated at 0.33 per cent.] The incidence of uveitis has been estimated at 0.18 per cent

Although the cornea usually is thinner after LASIK, because of the removal of part of the stroma, refractive surgeons strive to maintain a minimum thickness to avoid structurally weakening the cornea. Decreased atmospheric pressure at higher altitudes has not been demonstrated as extremely dangerous to the eyes of LASIK patients, however, some mountain climbers have experienced a myopic shift at extreme altitudes. There are no published reports documenting scuba diving-related complications after LASIK.

In situ keratomileusis effected at a later age increases the incidence of corneal higher-order wavefront aberrations. Conventional eyeglasses do not correct higher order aberrations.

Microfolding has been reported as "an almost unavoidable complication of LASIK" whose "clinical significance appears negligible".

Myopic (nearsighted) people who are close to the age (mid- to late-forties) when they will require either reading glasses or bifocal eyeglasses, may find that they still require reading glasses despite having undergone refractive LASIK surgery. Myopic people generally require reading glasses or bifocal eyeglasses at a later age than people who are emmetropic (those who see without eyeglasses), but this benefit is lost if they undergo LASIK. This is not a complication, but an expected result of the physical laws of optics.