Category — Important Articles

Some patients with poor outcomes from LASIK surgical procedures report a significantly reduced quality of life because of vision problems. Patients who have suffered LASIK complications have created websites and discussion forums to educate the public about the risks, where prospective and past patients can discuss the surgery. In 1999, Surgical Eyes was founded in New York City by RK patient Ron Link as a resource for patients with complications of LASIK and other refractive surgeries. Other patient-founded websites to assist those with complications are LaserMyEye founded in 2004 and Vision Surgery Rehab in 2005. Most experienced and reputable clinics will do a full-dilation medical eye exam prior to surgery and give adequate post-operative patient education care to minimize the risk of a negative outcome.

For best results, Steven C. Schallhorn, an ophthalmologist who oversaw the US Navy’s refractive surgery program and whose research partly influenced the Navy’s decision to allow its aviators to get LASIK, recommends patients seek out what’s called “all-laser Lasik” combined with “wavefront-guided” software.

The FDA website on LASIK clearly states: “Before undergoing a refractive procedure, you should carefully weigh the risks and benefits based on your own personal value system, and try to avoid being influenced by friends that have had the procedure or doctors encouraging you to do so.” As such, prospective patients still need to fully understand all the potential issues and complications, as satisfaction is directly related to expectation.

The FDA received 140 “negative reports relating to LASIK” for the time period 1998–2006.

The reported figures for safety and efficacy are open to interpretation. In 2003, the Medical Defence Union (MDU), the largest insurer for doctors in the United Kingdom, reported a 166 percent increase in claims involving laser eye surgery; however, the MDU averred that these claims resulted primarily from patients’ unrealistic expectations of LASIK rather than faulty surgery. A 2003 study, reported in the medical journal Ophthalmology, found that nearly 18 percent of treated patients and 12 percent of treated eyes needed retreatment. The authors concluded that higher initial corrections, astigmatism, and older age are risk factors for LASIK retreatment.

In 2004, the British National Health Service’s National Institute for Health and Clinical Excellence (NICE) considered a systematic review of four randomized controlled trials[18][19] before issuing guidance for the use of LASIK within the NHS. Regarding the procedure’s efficacy, NICE reported, “Current evidence on LASIK for the treatment of refractive errors suggests that it is effective in selected patients with mild or moderate short-sightedness,” but that “evidence is weaker for its effectiveness in severe short-sightedness and long-sightedness.” Regarding the procedure’s safety, NICE reported that “there are concerns about the procedure’s safety in the long term and current evidence does not appear adequate to support its use within the NHS without special arrangements for consent and for audit or research.”

Leading refractive surgeons in the United Kingdom and United States, including at least one author of a study cited in the report, believe NICE relied on information that is severely dated and weakly researched.

On October 10, 2006, WebMD reported that statistical analysis revealed that contact lens wear infection risk is greater than the infection risk from LASIK. Daily contact lens wearers have a 1-in-100 chance of developing a serious, contact lens-related eye infection in 30 years of use, and a 1-in-2,000 chance of suffering significant vision loss as a result of infection. The researchers calculated the risk of significant vision loss consequence of LASIK surgery to be closer to 1-in-10,000 cases.

The surveys determining patient satisfaction with LASIK have found most patients satisfied, with satisfaction range being 92–98 percent. A meta-analysis dated March 2008 performed by the American Society of Cataract and Refractive Surgery over 3,000 peer-reviewed articles published over the past 10 years in clinical journals from around the world, including 19 studies comprising 2,200 patients that looked directly at satisfaction, revealed a 95.4 percent patient satisfaction rate among LASIK patients worldwide.

Higher-order aberrations are visual problems that cannot be diagnosed using a traditional eye exam, which tests only for acuteness of vision. Severe aberrations can cause significant vision impairment. These aberrations include starbursts, ghosting, halos, double vision, and a number of other post-operative complications.

There have always been concerns about LASIK because of its tendency to induce higher-order aberrations. The advancement of the LASIK technology has helped reduce the risk of clinically significant visual impairment after surgery. There is a correlation between pupil size and aberrations.Effectively, the larger the pupil size, the greater the risk of aberrations. This correlation is the result of the irregularity between the untouched part of the cornea and the reshaped part. Daytime post-lasik vision is optimal, since the pupil is smaller than the LASIK flap. But at night, the pupil may expand such that light passes through the edge of the LASIK flap into the pupil which gives rise to many aberrations, including the appearance of halos surrounding sources of light. There are other currently unknown factors in addition to pupil size that also may lead to higher order aberrations.

In extreme cases in which ideal procedures were not followed by ophthalmologists, and before key advances, some people could suffer debilitating symptoms such as serious loss of contrast sensitivity in poor lighting situations.

Over time, most attention has shifted from other aberrations and centered on spherical aberration. LASIK and PRK tend to induce spherical aberration, because of the tendency of the laser to undercorrect as it moves outward from the center of the treatment zone. This is primarily an issue for major corrections. There are theories that posit that if the lasers were simply programmed to adjust for this tendency, no significant spherical aberration would occur. In eyes with few higher order aberrations, wavefront-optimized LASIK (rather than wavefront-guided LASIK) may well be the future.[citation needed]

Higher order aberrations are measured in micrometers (µm) on the wavescan taken during the pre-op examination, while the smallest beam size of FDA approved lasers is about 1000 times larger, at 0.65 mm. Thus imperfections are inherent in the procedure and a reason why patients experience halo, glare, and starburst, even with small naturally-dilated pupils in dim lighting.

Wavefront-guided LASIK

Wavefront-guided LASIK is a variation of LASIK surgery in which, rather than applying a simple correction of focusing power to the cornea (as in traditional LASIK), an ophthalmologist applies a spatially varying correction, guiding the computer-controlled Excimer laser with measurements from a wavefront sensor. The goal is to achieve a more optically perfect eye, though the final result still depends on the physician’s success at predicting changes which occur during healing. In older patients though, scattering from microscopic particles plays a major role and may outweigh any benefit from wavefront correction. Therefore, patients expecting so-called “super vision” from such procedures may be disappointed. Still, surgeons claim patients are generally more satisfied with this technique than with previous methods, particularly regarding lowered incidence of “halos,” the visual artifact caused by spherical aberration induced in the eye by earlier methods. Currently, there is no research in support of the surgeons’ claims.

There are several necessary preparations in the preoperative period. The operation itself involves creating a thin flap on the eye, folding it to enable remodeling of the tissue beneath with a laser. The flap is repositioned and the eye is left to heal in the postoperative period.

Preoperative

Patients wearing soft contact lenses are usually instructed to stop wearing them 5 to 21 days before surgery. One industry body recommends that patients wearing hard contact lenses should stop wearing them for a minimum of six weeks plus another six weeks for every three years the hard contacts have been worn.Before the surgery, the patient’s corneas are examined with a pachymeter to determine their thickness, and with a topographer to measure their surface contour. Using low-power lasers, a topographer creates a topographic map of the cornea. This process also detects astigmatism and other irregularities in the shape of the cornea. Using this information, the surgeon calculates the amount and the locations of corneal tissue to be removed during the operation. The patient typically is prescribed and self-administers an antibiotic beforehand to minimize the risk of infection after the procedure.

Operation

The operation is performed with the patient awake and mobile; however, the patient is sometimes given a mild sedative (such as Valium) and anesthetic eye drops.

LASIK is performed in three steps. The first step is to create a flap of corneal tissue. The second step is remodeling of the cornea underneath the flap with the laser. Finally, the flap is repositioned.

Flap creation

A corneal suction ring is applied to the eye, holding the eye in place. This step in the procedure can sometimes cause small blood vessels to burst, resulting in bleeding or subconjunctival hemorrhage into the white (sclera) of the eye, a harmless side effect that resolves within several weeks. Increased suction typically causes a transient dimming of vision in the treated eye. Once the eye is immobilized, the flap is created. This process is achieved with a mechanical microkeratome using a metal blade, or a femtosecond laser microkeratome (procedure known as IntraLASIK) that creates a series of tiny closely arranged bubbles within the cornea.A hinge is left at one end of this flap. The flap is folded back, revealing the stroma, the middle section of the cornea. The process of lifting and folding back the flap can sometimes be uncomfortable.

Laser remodeling

The second step of the procedure is to use an Excimer laser (193 nm) to remodel the corneal stroma. The laser vaporizes tissue in a finely controlled manner without damaging the adjacent stroma. No burning with heat or actual cutting is required to ablate the tissue. The layers of tissue removed are tens of micrometres thick. Performing the laser ablation in the deeper corneal stroma typically provides for more rapid visual recovery and less pain than the earlier technique, photorefractive keratectomy (PRK).

During the second step, the patient’s vision will become very blurry once the flap is lifted. They will be able to see only white light surrounding the orange light of the laser, which can lead to mild disorientation.

Currently, manufactured Excimer lasers use an eye tracking system that follows the patient’s eye position up to 4,000 times per second, redirecting laser pulses for precise placement within the treatment zone. Typical pulses are around 1 millijoule (mJ) of pulse energy in 10 to 20 nanoseconds.

Repositioning of flap

After the laser has reshaped the stromal layer, the LASIK flap is carefully repositioned over the treatment area by the surgeon and checked for the presence of air bubbles, debris, and proper fit on the eye. The flap remains in position by natural adhesion until healing is completed.

Postoperative care

Patients are usually given a course of antibiotic and anti-inflammatory eye drops. These are continued in the weeks following surgery. Patients are usually told to sleep much more and are also given a darkened pair of shields to protect their eyes from bright lights and protective goggles to prevent rubbing of the eyes when asleep and to reduce dry eyes. They also are required to moisturize the eyes with preservative-free tears and follow directions for prescription drops. Patients should be adequately informed by their surgeons of the importance of proper post-operative care to minimize the risk of complications.

The LASIK technique was made possible by the Colombia-based Spanish ophthalmologist Jose Barraquer, who, around 1950 in his clinic in Bogotá, Colombia, developed the first microkeratome, and developed the technique used to cut thin flaps in the cornea and alter its shape, in a procedure he called keratomileusis. Stephan Schaller assisted in this landmark procedure. Barraquer also researched the question of how much of the cornea had to be left unaltered to provide stable long-term results.

Later technical and procedural developments included RK (radial keratotomy), developed in Russia in the 1970s by Svyatoslav Fyodorov, and PRK (photorefractive keratectomy), developed in 1983 at Columbia University by Dr. Steven Trokel, who in addition published an article in the American Journal of Ophthalmology in 1983 outlining the potential benefits of using the Excimer laser in refractive surgeries. (RK is a procedure in which radial corneal cuts are made, typically using a micrometer diamond knife, and is completely different from LASIK).

In 1968 at the Northrup Corporation Research and Technology Center of the University of California, Mani Lal Bhaumik and a group of scientists were working on the development of a carbon-dioxide laser. Their work evolved into what would become the Excimer laser. This type of laser would become the cornerstone for refractive eye surgery. Dr. Bhaumik announced his team’s breakthrough in May 1973 at a meeting of the Denver Optical Society of America in Denver, Colorado. He would later patent his discovery.[2]

The general term for changing a patient’s optical measurements by means of an operation is Refractive Surgery. The introduction of lasers in refractive surgeries stemmed from Rangaswamy Srinivasan’s work. In 1980, Srinivasan, working at IBM Research Lab, discovered that an ultraviolet Excimer laser could etch living tissue in a precise manner with no thermal damage to the surrounding area. He named the phenomenon Ablative Photodecomposition (APD).[3]

The first patent for LASIK was granted by the U.S. Patent Office to Dr. Gholam A. Peyman on June 20, 1989, U.S. Patent #4,840,175, “Method for modifying corneal curvature,” encompassing the surgical procedure in which a flap is cut in the cornea and pulled back to expose the corneal bed. The exposed surface is then ablated to the desired shape with an Excimer laser, after which the flap is replaced.[citation needed]

The LASIK technique was successfully applied in other countries before it arrived to the United States. The first FDA trial of the Excimer laser was started in 1989. The first use of the laser was to change the surface shape of the cornea, known as PRK. Dr. Joseph Dello Russo was one of the ten original FDA researchers who tested and got approval for the Visx laser. The LASIK concept was first introduced by Dr. Palliakaris in 1992 to the group of ten surgeons who were selected by the FDA to test the Visx laser at 10 centers in the U.S.

Dr. Palliakaris theorized the benefits of performing PRK after the surface was raised in a layer to be known as a flap performed by the Mikrokeratome developed by Barraquer in 1950. The blending of a flap and PRK became known as LASIK, which is an acronym. It quickly became very popular, since it provided immediate improvements in vision and involved much less pain and discomfort than PRK.

Today, faster lasers, larger spot areas, bladeless flap incisions, intraoperative pachymetry, and wavefront-optimized and -guided techniques have significantly improved the reliability of the procedure compared to that of 1991. Nonetheless, the fundamental limitations of Excimer lasers and undesirable destruction of the eye’s nerves have spawned research into many alternatives to “plain” LASIK, including LASEK, Epi-LASIK, sub-Bowman’s Keratomileusis aka thin-flap LASIK, wavefront-guided PRK and modern intraocular lenses.

LASIK may one day be replaced by intrastromal ablation[4] via all-femtosecond correction (like Femtosecond Lenticule Extraction, FLIVC, or IntraCOR), or other techniques that avoid weakening the cornea with large incisions and deliver less energy to surrounding tissues. The 20/10 (now Technolas) FEMTEC laser has recently been used for incision-less ablation on several hundred human eyes and achieved very successful results for presbyopia,[5] with trials ongoing for myopia and other disorders.

LASIK or Lasik (laser-assisted in situ keratomileusis) is a type of refractive surgery for correcting myopia, hyperopia, and astigmatism. LASIK is performed by ophthalmologists using a laser. The procedure is generally preferred to photorefractive keratectomy, PRK, (also called ASA, Advanced Surface Ablation) because it requires less time for the patient’s recovery, and the patient feels less pain overall. However, there are instances where a PRK/ASA procedure is medically justified as being a better alternative to LASIK.

Many patients choose LASIK as an alternative to wearing corrective eyeglasses or contact lenses.

Q: Is LASIK painful?

A: While everyone’s level of pain tolerance is different, we have found that most patients do not find the procedure to be painful. You may feel slightly uncomfortable during and after the procedure, but rarely do our patients feel intense pain. A good way to get a first hand account of what the procedure might feel like is to speak with someone who has had the procedure. Let them describe to you in their own words the sensation they felt.

To counteract any discomfort you may experience, you are given anesthetic eye drops to numb the eyes right before the procedure. Some clinics offer a mild sedative an hour or so before the procedure for nerves. Once the procedure is complete, you will probably feel tired, or you may feel a foreign body sensation in your eyes. Most patients take naps once the procedure is complete, and this sensation usually disappears after the nap. The most common complaint is dry eyes, for which you are given or prescribed lubricating drops.

Q: Am I a candidate for LASIK?

A: You’ll know this after your Free Consultation with one of our clinics. But to begin with, you must be at least 18 years old to have the surgery. You also must be in good overall physical health, good eye health with no diseases like glaucoma or cataracts. Your Free Consultation will give you the opportunity to be examined by doctor and let him or her tell you whether you’re qualified to undergo the procedure. You’ll also have the opportunity to ask any questions you have, so that you are making an educated decision about the LASIK surgery.

Q: Which procedure am I eligible for?

A: If you’re exploring laser vision correction for nearsightedness, farsightedness or astigmatism, then you have the choice to under Conventional LASIK or Custom LASIK. It all depends on the level of customization you want - since Custom LASIK is far more tailored to your individual vision needs. You probably won’t be able to make this decision until you speak with your own eye doctor, or one of our LASIK experts. They will be able to identify all problem areas with your vision and recommend either Custom or Conventional LASIK.

Q: What is the price for LASIK?

A: The price is this procedure is different for every person because the cost is based on the level of refractive correction required, the location of the center, and each patients individual needs. The cost of Custom LASIK is generally more than Conventional LASIK because of the tailored procedure and the use of the most advanced technology in the vision industry. You’ll have a better idea of what the procedure will cost after your Free Consultation, where the doctors and LASIK experts can examine your eyes and determine your needs.

Q: What are the risks of LASIK?

A: As with any surgical procedure, there are a few risks that are associated with laser vision correction. Fortunately, numerous clinical studies have shown the chance of having a vision reducing complication has been very minimal. Remember, millions of of completely successful surgeries have been performs, and the satisfaction level of our patients exceeds 99%. Some potential complications can include eye dryness, night glare, complication in the surgical flap, under or over-correction, or loss of best-corrected vision. All of these and any other potential individual risks are discussed in full at the Free Consultation so that each patient is prepared to make an educated decision about continuing with the procedure. Extensive preoperative screening is performed so that we will only continue with the surgery when it is medically advisable to do so. Additionally, meticulous post-operative care helps to identify any potential healing problems that may arise.

Q: What is the recovery process?

A: Most LASIK patients see quite well within 24 hours after their surgery. Following your procedure, you will be given eye drops to combat any dryness you experience. You may feel tired, and we recommend taking a nap afterward. The speed of full recovery will be very different for each patient, but most patients should be fully recovered within only a few days after their procedure.