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CHAPTER IIntroduction LASIK surgery can be extremely successful in freeing patients from their glasses or contact lenses. It is important, however, that patients are realistic in their expectations of the surgery and comfortable with the surgery itself, the surgeon, the clinic and its staff. LASIK does have risks, and as someone considering the procedure you should be aware of those risks. The LASIK CONSUMER REPORT is written to help educate you about the entire LASIK experience. LASIK has enhanced my life beyond description. I hope this report will help you sift through the milieu of LASIK marketing. It is not prudent to tolerate "corners being cut" when it comes to your eyes. Please, insist on the highest standards. Are You a Candidate For LASIK? LASIK is a procedure that reshapes the cornea to improve vision. Appendix A provides more details on the LASIK procedure itself. LASIK can treat nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. Appendix B provides more detail on blurred vision from these conditions. These are conditions that require the use of glasses and contact lenses for clear vision. With some exceptions, LASIK generally treats myopia between -0.5 and -10 diopters, hyperopia between +0.5 and +6.0 diopters, and astigmatism between 0.5 and 6.0 diopters. Patients who have had previous eye surgery may qualify for LASIK. LASIK can be performed after previous radial keratotomy (RK), photorefractive keratotomy (PRK), and cataract surgery. LASIK can be performed on "lazy eyes" and eyes with nystagmus. Alternative Procedures to LASIK 1. IntacsTM 2. LTK 3. No-Cut
LASEKSM Even though glasses or contact lens prescriptions may fall within the diopter ranges above, there are conditions that make these procedures inappropriate until the conditions are treated or resolved. These include:
For purposes of this CONSUMER REPORT, LASIK will be emphasized as it represents the majority of vision correction procedures performed. . What to Expect From LASIK The Goal LASIK allows individuals greater independence from glasses or contacts by enabling them to have functional natural vision. LASIK has changed the lives of thousands of people (myself included), freeing them from their dependency on contact lenses and glasses. However, one needs to be realistic about the limitations of the vision-correction procedure. It is impossible to guarantee exact results due to the unique healing factor of each patient and potential variability of surgical technique, eye measurements, and equipment. Excellent surgeons can largely control the latter three variables. Individuals should not expect "perfect vision" even though surgeons will aim for it. Although over 50% of patients can achieve 20/20 vision, it is not essential to be 20/20 to be satisfied and functional in most, if not all, daily activities. The success rates can be as high as 90-97% with patients achieving 20/30 vision or better (20/25, 20/20). Such patients can function most if not all times without their glasses or contact lenses. If the vision is less than 20/30, then an enhancement LASIK procedure, glasses or contacts are options for additional improvement in vision. It is important to have realistic expectations of vision improvement to maximize your level of satisfaction. The Procedure You should expect the procedure to be relatively quick, usually under 15 minutes per eye. It should be painless. Immediately after the surgery, your vision may be fuzzy. This is normal. Typically, it takes six to eight hours to notice the initial recovery in vision, so it is important to be patient. The day of the surgery it is important to keep your eyes closed after surgery to allow for proper lubrication of the eye's surface during recovery. Before you leave the clinic to go home, your eyes should be examined again (usually 15 minutes to an hour following the procedure) to ensure that the flap is in good position. Valium (or an equivalent medicine) may be given as a sleeping aid. It is normal to experience some stinging or foreign-body-in-the-eye sensations after the procedure and patients should expect to use anti-inflammatory and antibiotic drops for the first four to seven days following the surgery. Frequent use of artificial tears (minimum of one drop four times a day) over the first month is helpful to lubricate the surface during the healing phase. By the next morning, patients should notice a dramatic improvement in vision. Patients are often thrilled to be able to read the alarm clock and look out the bedroom window and see trees or houses. The quick recovery of functional vision is impressive and often described as miraculous. Patients should have up to an 80-90% improvement in vision by the next morning after LASIK and can return to most routine activities promptly. It is not uncommon for patients to experience glare and halos at night during the first few weeks after surgery. This typically improves within the first three months following surgery and should not interfere nighttime activities. The glare and halo effect may be more pronounced in those with greater degrees of myopia, hyperopia and astigmatism. Additionally, patients must wear a shield or patch while napping or sleeping during the first week. The shield is important to protect the eye from being accidentally touched. It is essential to avoid rubbing or bumping the eye during the first month following surgery so as not to displace the flap. To monitor healing, patients should see the doctor the day after surgery, again at 1 month, 3 months, 6 months, and one year following the surgery. If a retreatment is required, this is typically determined after the three-month visit, when the eye is fully stabilized. (In some cases stabilization may require more than three months). ASK YOURSELF: If you do not know what to expect,
how can Choosing an Excellent Surgeon Choosing
your surgeon is the most important aspect of making the decision
Patients should seek out surgeons who are sincere, qualified, use quality equipment and processes. LASIK is a surgical procedure, not a product taken off a supermarket shelf. Thus, surgeons of varying skill quality using the same tools will achieve different outcomes. Talented baseball players and golfers use tools to achieve results; the same holds true for surgeons. However, having state-of-the-art equipment does not necessarily make for a talented user of that equipment. It is best to have confidence in your surgeon based on a face-to-face meeting, and to receive reasonable responses to questions you ask. I. Selecting A Surgeon With Sincerity Part of being comfortable with elective surgery is to believe the surgeon is sincere. Patients should be given the opportunity to meet with the surgeon to discuss their individual condition before the day of surgery. If a patient meets the surgeon on the day of surgery, the meeting should happen before going into the surgery room. A patient should not be comfortable committing to surgery if he or she has not met or spoken with the surgeon before the procedure. After meeting the surgeon, a patient should feel the surgeon is cordial, respectful, and caring. A surgeon who rushes in and out of the room during a consultation conveys a different message about patient care than the surgeon who spends time talking to the patient about his or her condition and concerns. Ultimately, you should feel the surgeon has your best interests at heart and really cares. In elective surgery such as LASIK, there should be ample time to carefully read the informed consent document prior to surgery. The consent form should never be signed under duress. ASK
YOURSELF: How can quality patient care be given if the II. Selecting A Surgeon Qualified In LASIK There
are two ways that ophthalmologists learn LASIK: A Fellowship in Refractive and Corneal Surgery entails a year of advanced training that occurs follows the completion of a 3-year ophthalmology training program. This training promotes better and more individually tailored vision-correction treatments for each patient. In the Fellowship, several principles are taught, including:
Advertising caution: You may hear that a doctor is a "fellow of the American Board of Ophthalmology". This "fellow" designation does not indicate that the surgeon completed a year fellowship in refractive surgery. It means that the surgeon completed the general ophthalmology exams - not a year fellowship in refractive surgery. One-year refractive and corneal surgery fellowships have only existed for the past seven years or so. Older surgeons who completed ophthalmology training before such fellowships existed are typically trained with a one to two day LASIK course. The course certifies the use of a specific laser and microkeratome and allows a surgeon to treat LASIK patients immediately after course completion. There are excellent LASIK surgeons trained this way, who have excellent reputations in their communities and were performing refractive surgery prior to the arrival of LASIK on the scene. If you are evaluating a surgeon who has not performed a one-year refractive and corneal surgery fellowship, it is appropriate to inquire if the surgeon has performed earlier forms of refractive surgery such as PRK and RK, procedures that existed prior to LASIK. It is also advisable to inquire whether potential surgeons are contributing to the field through research and/or are teaching other surgeons. You may read in their brochures that they "teach other doctors" and "perform important research". It would be appropriate to ask what they are teaching, to whom, and when? What are they researching, with whom and when? Is this a surgeon who taught glaucoma surgery at a meeting 10 years ago? Or is it a surgeon who is currently teaching the latest refractive surgery techniques to peers? And, is the surgeon being invited to conferences to teach about the latest diagnostic testing and surgical technique? Excellent surgeons are often recognized through awards and special honors. Does the surgeon's literature list any such distinctions? You many hear claims about clinic experience such as: "Our center performed more than 40,000 surgeries." If so, consider asking:
Remember, a surgeon does your procedure, not a center. A powerful way to determine whether the surgeon you are considering is a leader in the field is to search the Internet using the surgeon's last name. For example, go to www.google.com and type in the last name of a potential surgeon. This may identify attributable research or teaching presentations, or if the surgeon was featured in local or national news about refractive surgery.Check your surgeon's state license and any issues such as discipline or suspension at the Association of State Medical Board Executive Directors' website (www.docboard.org). ASK
YOURSELF: How can you be comfortable with the III. Selecting A Surgeon With Quality Equipment The lasers used in the United States should be approved by the Food and Drug Administration (FDA). A key feature, which differs between FDA approved lasers, is the range of treatment zones. At the time of this writing, the maximum treatment zone is 8.0 mm, but not all lasers are that broad. Large treatment diameters allow treatment of patients with large pupils and higher degrees of nearsightedness. The flapmakers should be the latest generation, which have a higher safety level than earlier models that are over 5 years old. The surgical equipment is only as good as the surgeon who uses it. IV. Selecting
A Surgeon With Quality Process 2. Use of Gloves. Bacteria are ubiquitous. These tiny organisms are especially prevalent on the skin, eyelids, and even on the surface of the eye itself. Some bacteria can cause infection, which is why using sterile technique in LASIK is important to minimize the risk of infection by preventing bacteria or bacterial debris from getting under the flap. The most sterile procedure is for surgeons to use separate sterile surgical gloves for each eye of each patient. 3. One or Two Sets of Microkeratomes and Instruments. There are three methods of performing LASIK on both eyes of a patient on the same day.
4. Instrument Cleaning Protocol. The surgical technician is responsible for the maintenance of the instruments. Therefore, all elements, including use and maintenance of the autoclave that heat-sterilizes the instruments, should be accomplished with a high level of meticulous care and diligence. If the autoclave is not cared for properly, bacteria can grow, which can contaminate the instruments with dead, toxic bacteria remnants.
Preoperative Evaluation Surgical Technique Now that you have an idea of matters to be considered in selecting a surgeon, the next step is to understand if the surgeon is properly testing your eyes. Maximizing the chance of a successful result is dependent on selection of appropriate patients through careful evaluation. Specific evaluations (I to V) must be done to determine if LASIK is appropriate: I. Tear film evaluation It is normal for patients to experience temporary dryness after LASIK. Patients who have inadequate tears before surgery are at higher risk of prolonged dry-eye symptoms after LASIK and should have increased lubrication before surgery. Some patients have the feeling of dryness while wearing contact lenses since lenses absorb tear moisture. This does not mean that the eyes are dry when contact lenses are not being worn. There are different methods to evaluate tear function: Some involve evaluation with a special "tearscope"; some place colored agents in the tears; another, physically measures the tears themselves. Visual inspection of the tear film with a microscope is another technique.
Following LASIK, some patients experience glare and halos. Often this is due to a combination of larger pupil sizes and higher amounts of nearsightedness or farsightedness that was not recognized as a risk factor prior to surgery. With large pupils, light rays from the peripheral cornea are more likely to cause symptoms of glare and halos after LASIK. These symptoms can be minimized by programming a larger optical zone of the laser for patients who have a combination of larger pupils and higher amounts of nearsightedness. If central optical zones are custom-programmed with lasers that have an adjustable central optical zone from 6.0 mm to 8.0 mm, even patients with large pupils and high prescriptions can do very well and avoid troubling glare, halos, and night-driving difficulties. To accomplish this, the surgeon must have a high level of understanding and experience with advanced laser and corneal optics in order to know how to program the laser based on a given individual patient's measurements.
1. Infrared. Infrared technology gives a digital readout of the pupil size, so there is no need for the examiner to make estimates. Infrared technology is the gold standard method to measure pupil size, albeit the most expensive. 2. Light amplification. An examiner looks through one end of the device at the pupil. Pupil diameter is measured against a tiny ruler in the viewfinder. 3. Ruler card. An examiner uses a hand-held card with different sized circles on it to match the diameter of the pupil to that of a circle on the card. 4. Visual estimation. Here the pupil size is "guestimated" by the examiner. This is the least accurate method.
Corneal topography shows the surgeon whether or not the cornea has normal astigmatism or abnormal astigmatism. Some patients with abnormal astigmatism have a condition called keratoconus, or "bulging of the cornea." These corneas often are weaker than normal corneas and thus should not be treated by LASIK.
Pachymetry is the medical term for "corneal thickness." As you already know, the LASIK procedure involves creating a flap on the surface of the cornea and using the laser to reshape the cornea by removing tissue. It is possible that too much tissue can be removed by the laser. This can destabilize the cornea and lead to corneal bulging. This condition is called ectasia and results in distorted vision. Before surgery, the surgeon should calculate how deep the laser will penetrate and be sure it does not penetrate beyond the safe level, which is why measuring corneal thickness is imperative.
Attached to the surface of the cornea there is a thin clear layer of "skin" or epithelium. In some patients, this layer of skin may not be firmly attached. If so, while making the flap in the LASIK procedure, this skin layer may be brushed off by the microkeratome, leading to a higher risk of complications. It is important to identify beforehand with a microscopic examination of the cornea if the "loose skin" condition exists.
Background of LASIK LASIK stands for Laser In-Situ Keratomileusis, which translates: "using a laser to reshape the cornea from the inside." It was first performed in 1991. The basic elements of the LASIK procedure involves the creation of a flap in the outer cornea; moving the flap to the side to expose the inner part of the cornea; using an excimer laser to reshape the cornea based on the patient's specific measurements, and then replacing the flap to its original position. The reshaped cornea then focuses the previously unfocused light rays onto the retina. At a more detailed level, LASIK is in fact two procedures combined: Microkeratome (Flapmaker) The first procedure, keratomileusis, which was developed in the late 1950s, employs a small surgical instrument: a microkeratome (much like a carpenter's plane) that creates smooth flaps with a mechanically oscillating tiny blade contained within a microkeratome metal head. The head is used in conjunction with a suction ring that holds the eye in position during the flap creation. (Back then, lasers were not developed for reshaping the cornea. To do so, the microkeratome was used a second time under the flap.) The same principles underlying the original microkeratomes are used in the modern microkeratomes. The long-term safety record of properly created flaps in the cornea is excellent, and many microkeratomes are currently FDA approved.
The excimer laser was developed in the 1980s for reshaping the eye. The precision wavelength of 193 nanometers was found to be the safest and most accurate. Many excimer lasers are FDA approved, but not all lasers have the same range of approvals. For example, one brand of laser may be FDA approved only for treating myopia without astigmatism, while another laser may be FDA approved for all five possible conditions: myopia with and without astigmatism, hyperopia with and without astigmatism, and mixed astigmatism. The most advanced lasers today are small spot (less than 2 mm) and have advanced eye-tracker technology that follows the eye during the laser application (this compensates for small eye movements). Such lasers have adjustable treatment zones up to 8.0 mm to compensate for large pupil diameters. Lasers have extremely sophisticated self-run computer diagnostics that verify this entire system during calibration testing. The most advanced lasers available today can correct myopia with/without astigmatism and hyperopia with/without astigmatism. Brief History of Refractive Surgery LASIK was developed from procedures described above. The excimer laser was initially developed to aid in a procedure called radial keratotomy (RK). In the early 1980s, RK involved changing the corneal shape for myopia by making tiny slits in the outer cornea with a special blade. The excimer laser was created in an attempt to replace the blade for RK surgery. Shortly afterwards
the excimer laser was used instead to directly reshape the central
cornea in a procedure called photorefractive keratectomy (PRK).
Background of Blurred Vision The eye functions much like a camera. The camera's lens, located in front, focuses the image on the film in the back of the camera. In the eye, there are two lenses-the cornea (outer lens) and crystalline lens (inner lens)-which focus the image on the retina, that lines the back wall of the eye (analogous to the film of a camera). In the eye, the pupil acts like a camera shutter, gauging which light rays are allowed to enter the eye through the cornea. The electrical impulses are sent to the brain through the cable-like optic nerve. The eye takes the picture, and the brain develops it into the image you actually see. The natural clarity by which some people see distance images without glasses or contact lenses indicates that the image is being focused on the retina. If the image is focused either in front or behind the retina, the image is blurry. A major factor determining the success of the image focused on the retina is the length of the eyeball:
Another condition that can blur vision is astigmatism, which indicates that the cornea is misshapen (like a football). Astigmatism can occur in combination with nearsightedness as well as with farsightedness. The ideal corneal shape is round (like a basketball). Presbyopia, when the lens inside the eye can no longer focus on closer reading material (books, menus, shopping tags, etc.), is the reason most people over 40 must use bifocals and reading glasses. Presbyopia, to some degree, eventually happens to everyone.
Eye doctors write prescriptions for glasses and contact lenses-usually a single number or three numbers-that indicate the condition of the eye:
Mild to moderate nearsightedness shows in the range of -1 to -6 diopters (the units of measurement). Mild to moderate farsightedness generally falls within the range of +0.75 to +4.00 diopters. The absence of a second or third number indicates there is no astigmatism. A second number verifies both the presence of astigmatism and the degree of it. Astigmatism may have either a minus sign or a plus sign. The third number, called axis, indicates the direction of astigmatism: right and left eye is designated by OD and OS, respectively. Two sample prescriptions for right eyes are:
Steps of LASIK The following is an outline of the basic steps of a typical LASIK procedure:
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