LASIK Surgery Risks and Complications and how to avoid them

LASIK Surgery Risks and Complications

LASIK and other types of laser eye surgery, such as PRK and LASEK, have an excellent safety profile and a very high success rate. They are designed to treat myopia (nearsightedness), hyperopia (farsightedness) and astigmatism, and can allow you to live without glasses or contacts.

Sight-threatening complications such as complete or partial loss of vision from LASIK surgery are extremely rare, and many side effects and laser eye surgery complications can be resolved with additional surgery or medical treatment.

Like any other surgery, however, there are potential risks, side effects and limitations you should be fully aware of before electing to undergo the procedure (or any type of procedure, for that matter). Choosing a skilled and experienced LASIK eye surgeon can help reduce these risks and enable you to achieve the best possible results from laser eye surgery.

The first step is to determine if you are a good candidate for vision correction surgery. Your eye doctor will perform an advanced diagnostic eye exam to determine your suitability for LASIK surgery. He or she will evaluate: the shape and thickness of your cornea; pupil size; refractive errors; the moistness of your eyes (to check for dry eye syndrome); general health and medical history; and any medications you are taking.

Even if you are not a good candidate for LASIK, don't worry — you might still be able to have your vision fixed with other vision correction surgery such as PRK, LASEK or implantable lenses.

LASIK Eye Surgery Risk Factors and Limitations

Not everyone is a suitable candidate for LASIK eye surgery. Certain conditions and anatomical factors can increase your risk of an undesirable outcome or limit optimal LASIK results. These include:

• Too thin or irregular corneas
• Large pupils
• High refractive error
• Unstable vision
• Dry eyes
• Your age
• If you are pregnant
• If you have certain degenerative or active autoimmune disorders

For a full checklist on LASIK risk factors and whether or not you are an appropriate candidate, read our LASIK Criteria for Success.

LASIK Side Effects and Complications

Millions of Americans have had LASIK eye surgery to correct their vision since it was introduced in the United States more than 20 years ago, and experienced LASIK surgeons report that serious complication rates can be held below 1 percent.

Common LASIK complications and side effects are listed below. Most of these problems can be resolved with medical treatment or additional "enhancement" surgery.

Temporary discomfort and vision disturbances. Discomfort during the first few days following LASIK surgery, such as mild irritation and light sensitivity, is normal and to be expected. During the first few weeks or months you also may experience: halos; glare and starbursts in low-light environments, especially at night; dry eye symptoms; hazy vision; and reduced sharpness of vision. In the vast majority of cases, these problems are temporary and disappear completely within three to six months.

Flap complications. The LASIK procedure involves the creation of a thin hinged flap on the front surface of the cornea. This is lifted during surgery for laser reshaping of the eye. The flap is then replaced to form a natural bandage.
If the LASIK flap is not made correctly, it may fail to adhere properly to the eye's surface or cause microscopic wrinkles in the flap called corneal striae (STRIE-ee). These flap complications can lead to an irregularly shaped eye surface and distorted vision.
Studies indicate that flap complications occur in from 0.3 to 5.7 percent of LASIK procedures, according to the April 2006 issue of American Journal of Ophthalmology. In a study of 3,009 consecutive LASIK surgeries performed August 2002 through July 2009 using a femtosecond laser for flap creation, flap complications occurred in fewer than one-half of 1 percent (0.37 percent) of these procedures, and all complications were successfully managed within the same surgical session.
Again, remember that you can reduce your risk of LASIK complications by choosing a reputable, experienced eye surgeon.
Some problems associated with LASIK flap complications include:

• Irregular astigmatism. This is caused by an unequally curved corneal surface. Irregular astigmatism also can occur from laser correction that is not centered properly on the eye or from irregular healing. Resulting symptoms may include double vision (diplopia) or "ghost images." In these cases, the eye may need re-treatment or enhancement surgery.
• Epithelial ingrowth. This is when cells from the outer layer of the cornea (epithelium) grow under the flap after LASIK surgery. In most cases, epithelial ingrowth is self-limiting and causes no problems. But in some cases (reported to be 1 to 2 percent of LASIK procedures), symptoms of discomfort and/or blurred vision can occur, and additional surgery is needed to lift the flap and remove the epithelial cells.
• Diffuse lamellar keratitis (DLK). Nicknamed "Sands of the Sahara," this is inflammation under the LASIK flap that may have several causes. Some inflammation of the cornea after LASIK surgery is normal. But if it is uncontrolled, as in DLK, it can interfere with healing and cause vision loss. If DLK occurs, it usually responds to therapies such as antibiotics and topical steroids. Also, the flap might need to be lifted and cleaned for removal of inflammatory cells and to prevent tissue damage.
• Keratectasia or keratoconus. This is a very uncommon bulging of the eye's surface that can occur if too much tissue is removed from the cornea during LASIK or if the cornea prior to LASIK is weak as evidenced from corneal topography mapping. Rarely does keratoconus develop after LASIK with no known risk factors.
  
  Enhancement laser surgery is usually not suitable, and gas permeable contact lenses or corneal implants (Intacs) may be prescribed to hold the cornea in place, or a treatment called corneal collagen crosslinking may be performed to strengthen the cornea. 

Dry eyes after LASIK. 

Some people who have LASIK surgery experience a decrease in tear production that can cause eye discomfort and blurred vision. Almost half of all LASIK patients experience some degree of temporary dry eye syndrome, according to the April 2006 issue of American Journal of Ophthalmology.
Dry eye syndrome after LASIK surgery usually is temporary and can be effectively treated with lubricating eye drops or other measures.
Dry eye problems usually disappear when healing of the eye is complete, which can take up to six months. People who already have severe dry eye usually are eliminated as LASIK candidates.
Significant undercorrection, overcorrection or regression. Not everyone will achieve 20/20 vision after LASIK eye surgery, and contacts or eyeglasses for some or all activities may still be required in rare cases. If the laser removes too much or too little corneal tissue, or your eye's healing response is not typical, your visual outcome will be less than optimal.
In many cases, the cause of a less-than-perfect outcome is that your eyes did not respond to laser eye surgery in a predictable manner. Another possible cause is that your eyesight may be optimal at first but regress over time due to "over-healing."
In most cases, a significant undercorrection or regression can be treated with additional laser vision correction or other refractive surgery methods such as conductive keratoplasty, once it is certain that the refractive error is stable.
Eye infection. While rare, LASIK surgeons report that infections occur more frequently with surface ablations such as PRK. At the 2008 annual meeting of the American Society of Cataract and Refractive Surgery (ASCRS), researchers reported that the LASIK flap, which is lifted during surgery and then replaced to serve as a type of natural "bandage," seemed to create a more sterile surgical environment than PRK and other surface ablation procedures, thereby reducing the risk of infection.
Eye infections after LASIK surgery typically are temporary, and can be treated with antibiotic eye drops or anti-inflammatory medication such as steroids.

LASIK Complications: How They Affect You, How They're Treated

Complications	Symptoms	Treatments
Incomplete corrections (undercorrection, overcorrection, residual astigmatism) or regression of effect	Blurry, less-than-perfect vision	Glasses or contact lenses; eye drops; re-treatment with laser
Decentered ablations	Visual aberrations*	Eye drops; re-treatment with laser
Oversize pupils	Visual aberrations*	Eye drops; re-treatment with laser
Haze	Visual aberrations*	Eye drops; re-treatment with laser
Irregular flap (folds, wrinkles, striae)	Visual aberrations*	Surgical correction; second laser procedure
Dry eye	Dry, itchy or scratchy eyes, often with redness and sense of foreign object in eye, and sometimes pain	Prescription dry eye medication; artificial tears; punctal occlusion (blockage of tear ducts in order to retain tear film on eye), oral flaxseed oil
Diffuse lamellar keratitis (eye inflammation)	Visual aberrations*	Eye drops; surgical rinsing of cells if severe
Epithelial ingrowth	Visual aberrations*	Surgical removal of epithelium
Infection	Redness, oozing of eyes, sometimes pain	Eye drops; oral medications
*Visual aberrations include symptoms such as glare, double vision, ghosting, halos, starbursts, loss of contrast sensitivity, and problems with low-light or night vision. Most patients do not experience these symptoms, and some patients with these complications experience no symptoms and require no treatment. [See also: Higher-Order Aberrations.] Chart created by Keith Croes and reviewed by Brian Boxer Wachler, MD.