Risks and Complications

Asking Doctor a QuestionLASIK is a surgical procedure, and like all surgeries, it possesses the potential for risks and complications. It’s important to note that the chance of a serious vision-threatening complication is very rare (much less than 1 percent), and for an experienced LASIK surgeon, even lower. Other side effects, for most patients, are temporary and can be addressed with medications or an enhancement procedure. Every patient should weigh the possibility of experiencing complications against the potential benefits LASIK will offer. The following information is provided to you to make such an informed decision.

Unrealistic Expectations

It is wise for those who undergo LASIK vision correction surgery to be fully informed and carefully assess their expectations. Patients with realistic expectations prior to surgery are the happiest with their results. As a patient, your job is to understand exactly what the procedure can and cannot do. This is where communication with your doctor is essential. Your doctor should understand all of your expectations, and then explain what is realistic and what is not.

With LASIK a skilled surgeon can significantly reduce your dependence on glasses and contact lenses, but eventually most patients will need glasses for reading in their late 40’s or 50’s. Some may even need a thin pair of glasses for critical distance activities such as driving at night. It is best to think of this procedure as not eliminating but reducing your dependence upon glasses and contact lenses.

Eyesight Changes

Eyesight can change slightly over time, from one year to the next, even if you do not undergo surgery. Following LASIK, your eyes may still change slightly, not because the procedure was unstable, but rather because eyes simply change. For the vast majority of people, their vision will not change enough to require the procedure to be performed again. If needed, LASIK enhancements are generally easily performed and have a quick recovery when performed by an experienced surgeon.

Post-LASIK Enhancement

LASIK keeps the surface corneal epithelium intact, which acts as a barrier to infection and helps to make this most feared complication extremely rare. Loss of best corrected vision is also quite rare, but if it does occur, it tends to improve over time as well.

Enhancement or “fine-tuning” procedures, if necessary, are performed after vision stabilizes three months or later after the initial procedure.

Dr. Tylock is committed to providing you with all the information you need to feel comfortable about making the choice to have vision correction surgery. After viewing our website if you would like to have more information, we invite you to attend one of our FREE Tuesday night laser eye care seminars or schedule an appointment with one of our patient counselors

Dry Eye

Some patients may experience a “dry” feeling in their eyes following LASIK. This condition usually tends to resolve itself over the first one to three months. In the meantime, adequate application of the lubricating eye drops recommended by your surgeon will often alleviate the symptoms.

It is important that you are evaluated for dry eye prior to the LASIK procedure. Tell your doctor if you experience dry eye symptoms with contact lenses or glasses. If dryness exists prior to surgery, or if dry eye symptoms persist after surgery despite the frequent use of artificial tears, your doctor may recommend blocking your tear drainage canals with punctal plugs. This brief, painless procedure prevents your natural tears from draining away so quickly and results in improved lubrication of the surface of the eye.
Dry eye patients benefit from IntraLASIK because they have much less dry eye symptoms and a quicker recovery compared to patients having traditional LASIK where the flap is made with a microkeratome and a blade. Therefore any patients that have dry eyes preoperatively are always directed to have the IntraLASIK procedure.

Our policy is to treat our patients’ dry eye condition so it is under control prior to refractive surgery. This avoids potential problems and allows the patients a comfortable and quick post-operative recovery.

Corneal Abrasions & Epithelial Loose Spots

The top outer layer of the cornea is called the epithelium. It is possible to develop a small corneal abrasion or surface epithelial loose spot during LASIK. Despite excellent surgical technique and an adequately moistened eye, a small breakdown or looseness in the epithelial surface may develop as the flap is made. This occurs in approximately 3 percent of traditional LASIK and less than 1 percent of the more gentle IntraLASIK procedures because some patients’ surface epithelial cells inherently do not adhere well. The medical term for this is latent epithelial basement membrane disorder. Unfortunately, doctors cannot always detect this preoperatively. A very thin bandage contact lens may be placed on the eye if this occurs. It improves comfort and promotes healing. The bandage contact lens is usually removed the next day. Fortunately, the epithelium grows back so fast that eyes with an epithelial defect usually heal within one to three days. Your vision will be blurred during the time that the abrasion or loose spot is healing. Long-term effects are rare.

Under Correction/Overcorrection and Enhancements

These situations occur because of differences among patients such as slight variations in corneal water content, corneal tissue healing differences, and other surgical variables. The uncertainty of these variables is why a surgeon cannot guarantee a specific result from LASIK surgery. The incidence of under correction varies with prescription and is more common in patients with higher levels of nearsightedness, farsightedness, or astigmatism. For example, a patient with a prescription of less than 3.00 diopters of myopia has about a 1 percent chance of needing an enhancement procedure. On the other hand, patients with 9.00 to 12.00 diopters of myopia have a 6 to 8 percent chance of having an enhancement procedure.

The addition of more laser treatment (enhancement) to correct an over or under response to LASIK is generally performed three to six months after the original treatment and at no additional cost to the patient in our office for up to a year after the primary surgery. The original flap created during the LASIK procedure is loosened and lifted with a specially designed instrument. There is usually no need to cut a new flap; thus, the risks associated with creating the flap originally are not a factor in re-treatment. The postoperative course is the same as with the original procedure.

Night Glare and Halos

Many nearsighted patients who wear glasses or contacts have symptoms of glare or see halos or starbursts at night. This is due to having longer eyes than normal sighted patients. Thus, at night in a nearsighted patient when the pupil dilates, peripheral light rays are scattered more before they reach the retina. It is this scattering that results in glare and halos.

These symptoms are sometimes more bothersome after laser surgery, especially if the pupil dilates beyond the size of the treatment zone. While many patients may see halos or a ghosting of images at night during the first month following treatment, it is rare for these side effects to interfere with their activities. The effects almost always clear in the first three months, and the overwhelming majority of significant glare problems resolve on their own by six months.

Patients that have residual under corrections, overcorrections or astigmatism after LASIK will most often experience some glare, halos or aberrations with their night vision until their vision is corrected by glasses, contacts, or enhancement surgery. If problems with glare do persist, patients tend to benefit from weak prescription night glasses or from the use of eye drops at dusk that reduce the size of their pupils.

Some patients with very widely dilating pupils and large corrections may not be optimal candidates for LASIK, as their risk of glare and halos may be higher. Customized laser treatment programs, such as the ones used with our WaveLight® EX 500 Hz Excimer Laser with 9.0mm treatment zones, can greatly reduce the chance of these problems. Also excimer laser tracking devices which assure the centration of treatment directly over the pupil minimize the incidence of glare and halos. The WaveLight® EX 500 Hz has the greatest sensitivity (compared to any other laser released in the United States) in adjusting to eye movements allowing the greatest precision, placement and safety for the patient. It is important for your surgeon to know if you have problems with glare prior to your surgery.

Loss of Best-Corrected Visual Acuity

A patient’s best-corrected visual acuity is defined as the best vision they can achieve with glasses or contact lenses as measured by an eye chart. A patient’s visual acuity post-LASIK is compared to this pre-surgical benchmark. A small number of patients experience a slight loss of visual sharpness or crispness following LASIK surgery although many experience a slight improvement in best-corrected vision.

A reduction in best corrected vision can occur when patients develop significant haze, diffuse lamellar keratitis, or persistent striae (tiny wrinkles or folds in the flap). These typically are short-term conditions during the initial months of healing and are almost always resolved as the healing process progresses. It is extremely rare that these conditions lead to a reduction of two or more lines of vision.
The part of the LASIK procedure that has the most potential risk is making the corneal flap with the blade and microkeratome. Since the addition of the more advanced, safer Femtosecond Laser, which makes the flap in IntraLASIK, loss of best corrected acuity has virtually been eliminated. Our WaveLight® FS200 kHz Femtosecond Laser sets a new industry standard for patient safety and comfort with the most advanced technologies available anywhere today. It also has the shortest treatment times to make the flap, approximately 6 seconds.

Summary

Prior to surgery it is most important that the patient have realistic expectations and understand the natural limitations of the eye, such as presbyopia. The vast majority of complications with LASIK are evident less than 24 hours after the procedure and related to the flap shifting or having a film under the flap. The eye may have been inadvertently bumped or rubbed after surgery. Dry eyes can cause friction between the flap and eyelid and can cause flap displacement in the first 24 hours following surgery before flap adherence builds significantly. Almost all of these flap shifting problems can be prevented with appropriate control of dry eyes, addressing eyelid closure problems, turning off ceiling fans, following instructions and lubricating your eyes as directed in this immediate postoperative period. Some rare patients may have film under their flaps that needs to be cleaned out in the first one to three days following surgery. These flap problems slow visual recovery but are readily corrected if handled early in the postoperative course and seldom cause long-term side effects. We have also found that these flap problems are less common with IntraLASIK as compared to traditional LASIK. The IntraLASIK flap is much more customized for the patient’s’ eye and more gentle on the surface epithelium giving the flap more stability post operatively.

Halos seen at night are common in the early postoperative period and usually resolve in four to six weeks.

For an in depth discussion of possible LASIK risks and complications, schedule a consultation with Dr. Tylock or Dr. George.