LASIK surgery is laser surgery to correct certain vision problems. People whose blurry vision can be corrected with glasses or contact lenses have a “refractive error”. LASIK corrects the refractive error, and is therefore a form of refractive surgery. LASIK surgery reshapes the part of the eye known as the cornea so that it focuses light better thus correcting blurry vision. In LASIK surgery, the surgeon first cuts a flap in the cornea with a very sharp blade or laser. She then lifts the flap and uses a computer-guided laser to remove tissue from the inside layers of the cornea.
Complications as a result of LASIK can threaten vision and may cause debilitating symptoms in an otherwise healthy eye: Schallhorn SC, Amesbury EC, Tanzer DJ. Avoidance, recognition, and management of LASIK complications. Am J Ophthalmol. 2006 Apr;141(4):733-9.
Alternatives to LASIK
Eyeglasses and contact lenses are alternatives to LASIK surgery. Orthokeratology, or corneal reshaping, is a non-surgical alternative provided by your doctor of optometry (optometrist) that gives eligible patients perfect vision without contacts or eyeglasses. As an added benefit, orthokeratology has been shown to stop your vision from getting worse.
Risks & Complications of LASIK surgery
Some patients suffer permanent vision loss. For these patients, LASIK makes their vision worse and the lost vision cannot be regained and it cannot be improved with glasses, contact lenses, surgery or other treatments.
Serious and debilitating vision problems
Some LASIK patients develop glare, halos, and/or double vision that can seriously affect nighttime vision. Even with good visual acuity (i.e. a person may have 20/20 vision on the vision chart) some LASIK patients do not see as well in situations of low contrast, such as at night or in fog, after treatment as compared to before treatment.
You may spend the money for surgery but still need to use glasses or contacts
Only a certain percent of LASIK patients achieve 20/20 vision without glasses or contacts. Patients may require additional treatment, but additional treatment may not be possible depending on the circumstances of each patient. Patients may still need glasses or contact lenses even after LASIK surgery. This may be true even if you only required a very weak prescription before surgery. Furthermore, if you used reading glasses before surgery, you may still need reading glasses after surgery.
Moreover, young people who get LASIK will likely be back in glasses for reading when the reach age 40 or so and LASIK cannot get you out of reading glasses. This is because the need for reading glasses arises when age makes the lens of the eye too rigid to flex and focus light properly - LASIK can't fix that.
Flap complications – when the surgeon’s knife-cut into the eye causes problems
The flap in the cornea that the surgeon cuts with a knife as part of the LASIK procedure does may not heal well and is prone to injury and other complications, sometimes even years after surgery. Even something as simple as a finger in the eye can cause the flap to dislodge or become dislocated.
For people who have lifestyles or occupations where impacts to the eye are possible (participants in sports, military personnel), LASIK is not recommended.
Diffuse Lammellar Keratitis
Pain, blurred vision, the sensation that something foreign is in the eye, and sensitivity to light are hallmarks of Diffuse Lammellar Keratitis (DLK), but for some patients the only symptom they experience is hazy vision. DLK happens when dead cells enter the eye at the flap that was cut by the surgeon. DLK most often appears within one to six days after surgery it has been known to occur months and even years after surgery. If it is not properly treated, it can affect vision. DLK is often called “sands of Sahara syndrome” because when a doctor looks at the eye through an instrument, it looks like there are waves of sand in it.
DLK affects between 2-4% of LASIK patients: Azar DT, Koch DD. LASIK: Fundamentals, Surgical Techniques,and Complications. Refractive surgery, 1. New York, NY: Marcel Dekker; 2003.
DLK is another complication that happens when epithelial cells at the flap that the surgeon cut into the eye go where they shouldn’t.
Microbial keratitis is an infection of the of the cornea by microscopic organisms like bacteria. It is taken seriously and can lead to blindness. LASIK treatment is a predisposing factor for bacterial keratitis even years after surgery. It is important for patients and doctors to be vigilant after LASIK surgery.
In one recent research study published in the Journal of Refractive Surgery, the researchers noted that “keratitis after LASIK is a devastating, vision threatening complication. It is not uncommon to see reports of keratitis after LASIK in the ophthalmic literature.” The authors estimate that the incidence of keratitis is between 1 in 1000 and 1 in 5000 procedures but note that the true incidence may be greater because many cases of infection are not reported. See Garg P., Chaurasia S. et al., Microbial Keratitis After LASIK. Journal of Refractive Surgery. Vol. 26 No. 3 March 2010.
Irregular astigmatism caused by epithelial implantation and ingrowth
Astigmatism is a condition characterized by the elongation of the eye: imagine squeezing a tennis ball. It causes visual distortions and blurry vision. LASIK can cause this to happen in a process where cells from the surface of the eye somehow get into the inside of the eye during surgery where they attach themselves and grow. In normal eyes these surface cells never get inside the eye and the condition is very abnormal and causes some bad and unpleasant things to happen to the eye.
The epithelial cells may block aqueous diffusion, which may compromise the nutrition of the flap and this could cause the cornea of the eye to melt. The epithelial cells may also produce enzymes that break down proteins and these enzymes can make melting of the cornea at the flap even worse. The problems caused by epithelial cells may be more common after LASIK enhancement surgery (when a patient gets a second procedure because they feel their vision is not good enough or has gotten worse over time after the first surgery) because the lifting of the flap can cause more epithelial cells to go where they can cause damage.
In 1% of patients, epithelial ingrowth is serious enough to require more surgery to fix it:Schallhorn SC, Amesbury EC, Tanzer DJ. Avoidance, recognition, and management of LASIK complications. Am J Ophthalmol. 2006 Apr;141(4):733-9.
Hole in the eye, also called a corneal perforation
There have been reports of the cornea being perforated during LASIK surgery.
Wrinkles of Folds in the LASIK flap
Yet another problem with the flap that the surgeon cuts is that the flap can cause folds or wrinkles in the cornea. Folds and wrinkles will make you vision worse. The incidence of this complication has been reported to be as high as 10% with surgeons who have less experience. See Gimbel HV, Basti S, Kaye GB, Ferensowicz M. Experience during the learning curve of laser in situ keratomileusis. J Cataract Refract Surg 1996; 22:542–550.
Corneal ectasia is a devastating complication of LASIK surgery that can lead to permanent vision loss. It causes the cornea to become deformed into a pointy cone shape. This causes serious visual distortions and does not have a reliable treatment. It is a condition resembling keratoconus and, like the latter, it can progress to blindness. Corneal ectasia can arise months or even years after an apparently uncomplicated procedure.
There is no cure for ectasia. However, there are a few things that doctors can do to manage ectasia such as the use of hard contact lenses, drugs to lower the pressure inside the eyes and intracorneal ring segments (known as INTACS). A corneal transplant may be required. Corneal collagen cross-linking (also known as CXL or C3R), is a relatively new, experimental treatment for ectasia using riboflavin and UVA light.
Severe dry eye syndrome
Dry eyes (also known as tear dysfunction syndrome, dry eye syndrome, dry eye disease) is the most common complication following LASIK surgery. While various studies make differing conclusions, there is a consensus that most LASIK patients will suffer from dry eye in the months following surgery, some will experience it for many months and according to the US Food and Drug Administration for some patients dry eye syndrome may be permanent.
One study concluded that up to 48% of patients complain of dryness symptoms during the ﬁrst six months after surgery; soreness of the eye to touch has been reported in 6.7% of LASIK patients, and sharp pains have been reported in 8.0% of LASIK patients: Hovanesian JA, Shah SS, Maloney RK. Symptoms of dry eye and recurrent erosion syndrome after refractive surgery.J Cataract Refract Surg 2001;27:577–584.
However, another study suggested that dry eye following LASIK may not be transient but more permanent in nature: Di Pascuale MA, Liu TS, Trattler W, Tseng SC Lipid tear deficiency in persistent dry eye after laser in situ keratomileusis and treatment results of new eye-warming device. J Cataract Refract Surg. 2005 Sep;31(9):1741-9.
It is thought that LASIK causes dry eye because the procedure cuts the nerves in the cornea thereby compromising the body’s ability to normally manage the tear film that prevents healthy eyes from getting dry. Fewer nerves means less sensation in the cornea which may reduce tear production but it also reduces the rate of blinking which also contribute to dry eye.
As a result of LASIK surgery, your eye may not be able to produce enough tears to keep the eye moist and comfortable. Dry eye not only causes discomfort, but can reduce visual quality due to intermittent blurring and other visual symptoms.
According to the United States Food and Drug Administration, dry eye syndrome following LASIK may be permanent and intensive drop therapy and use of plugs or other procedures may be required to treat and manage severe dry eye syndrome.
Severe dry eye impacts a patient’s general quality of life and has been linked to increased depression and anxiety: Li M, Gong L, Sun X, Chapin WJ. Anxiety and depression in patients with dry eye syndrome. Curr Eye Res. 2011 Jan;36(1):1-7.
Recurrent corneal erosions
LASIK has been known to cause recurrent corneal erosion, where the cornea's outermost layer of epithelial cells fails to attach properly to the underlying basement membrane (Bowman's layer). The condition is excruciatingly painful because the loss of these cells results in the exposure of sensitive corneal nerves.
Halos, glare, starbursts
LASIK can induce optical aberrations that can impair high quality vision. Halos, glare and starbursts are visual distortions or aberrations that interfere with vision and all have been shown in studies to be caused by LASIK. In one study, halos were reported by 30%, glare by 27%, and starbursts by 25% of all patients. See: Bailey MD, Mitchell GL, Dhaliwal DK, Boxer Wachler BS, Zadnik K. Patient satisfaction and visual symptoms after laser in situ keratomileusis. Ophthalmology. 2003 Jul;110(7):1371-8.
If you have a high lens prescription, LASIK won’t be as effective
Patients with high prescriptions should discuss their expectations with their doctor and have a clear understanding of the limitation of LASIK. Some patients with high prescriptions might still need glasses or contacts even after LASIK surgery. People in this situation need to carefully consider whether LASIK is worth the cost.
For some farsighted patients, results may diminish with age
If you are farsighted, the level of improved vision you experience after surgery may decrease with age. This can occur if your manifest refraction (a vision exam with lenses before dilating drops) is very different from your cycloplegic refraction (a vision exam with lenses after dilating drops).
Long-term data are not available
LASIK is a relatively new technology. The first laser was approved for LASIK eye surgery in 1998. Therefore, the long-term safety and effectiveness of LASIK surgery is not known.
Over and under correction
The surgeon may make mistakes in the operation of the LASIK laser machines. These mistakes can cause dramatic over-correction or under-correction of your vision. This is one of the most common LASIK complications: Schallhorn SC, Amesbury EC, Tanzer DJ. Avoidance, recognition, and management of LASIK complications. Am J Ophthalmol. 2006 Apr;141(4):733-9.
Financial conflict of interest
The fact that LASIK surgery is a business with large overhead costs ( the cost of the laser is in the hundreds of thousands of dollars in addition to the normal overhead costs of running a clinic and advertising) has led some authors to comment on the conflict of interest present in a situation where the doctor assessing a patient and recommending the procedure will only make money if he or she does the surgery. As one physician commented:
“It is critical that patients and primary care physicians understand ophthalmologists’ financial stake in the LASIK procedure. The laser costs hundreds of thousands of dollars, and many ophthalmologists own their own laser. Therefore, there is a clear financial motivation to perform more procedures. The potential for adverse effects may be downplayed, and patients may be encouraged to undergo the procedure before thoroughly exploring alternatives.”
Bieler BM. Quality of life after LASIK: the picture remains hazy. Am Fam Physician. 2010 Nov 1 ;82(9):1044-6; discussion 1044-6.
Xiao JH, Zhang MN, Jiang CH, Zhang Y, Qiu HY. Laser in situ keratomileusis surgery is not safe for military personnel Chin J Traumatol. 2012 Apr 1;15(2):77-80.
Ferrer C, Rodriguez-Prats JL, Abad JL, Claramonte P, Alió JL, Signes-Soler I. Pseudomonas keratitis 4 years after laser in situ keratomileusis. Optom Vis Sci. 2011 Oct;88(10):1252-4.
Nettune GR, Pflugfelder SC. Post-LASIK tear dysfunction and dysesthesia. Ocul Surf. 2010 Jul;8(3):135-45.
Li M, Gong L, Sun X, Chapin WJ. Anxiety and depression in patients with dry eye syndrome. Curr Eye Res. 2011 Jan;36(1):1-7.
Bailey MD, Mitchell GL, Dhaliwal DK, Boxer Wachler BS, Zadnik K. Patient satisfaction and visual symptoms after laser in situ keratomileusis. Ophthalmology. 2003 Jul;110(7):1371-8.
Schallhorn SC, Amesbury EC, Tanzer DJ. Avoidance, recognition, and management of LASIK complications. Am J Ophthalmol. 2006 Apr;141(4):733-9.
Azar DT, Koch DD. LASIK: Fundamentals, Surgical Techniques,and Complications. Refractive surgery, 1. New York, NY: Marcel Dekker; 2003.
Pop M, Payette Y. Photorefractive keratectomy versus laser in situ keratomileusis: a control-matched study. Ophthalmology 2000;107:251–257.
Hersh PS, Steinert RF, Brint SF. Photorefractive keratectomy versus laser in situ keratomileusis: comparison of optical side effects: Summit PRK-LASIK study group. Ophthalmology 2000;107:925–933.
Brunette I, Gresset J, Boivin JF, et al. Functional outcome and satisfaction after photorefractive keratectomy: part 2, survey of 690 patients. Ophthalmology 2000;107:1790 –1796.
Oshika T, Miyata K, Tokunaga T, et al. Higher order wavefront aberrations of cornea and magnitude of refractive correction in laser in situ keratomileusis. Ophthalmology 2002;109:1154 –1158.
Helgesen A, Hjortdal J, Ehlers N. Pupil size and night vision disturbances after LASIK for myopia. Acta Ophthalmol Scand 2004;82:454 – 460.
Schallhorn SC, Kaupp SE, Tanzer DJ, et al. Pupil size and quality of vision after LASIK. Ophthalmology 2003;110:1606 –1614.