Lasik Eye Procedure
The revolutionary procedure known as LASIK has become one of the most popular and successful in the world today. LASIK is the most commonly used surgical procedure for correcting short-sightedness (myopia), long-sightedness (hypermetropia), and astigmatism.
The Wavefront technology is groundbreaking because it has the potential to improve not only how much patients see as measured by the standard 20/20 eye chart, but also how well they see in terms of contrast, sensitivity and fine detail. By creating a 3D map of the eye’s ability to process images, the laser is guided to reshape the cornea which is designed to correct vision defects such as short-sightedness, long-sightedness, astigmatism and presbyopia.
An ultra-thin flap is created on the eye's surface during LASIK corrective eye surgery. After laser energy is applied to reshape the eye, the flap is replaced to serve as a type of natural bandage.
The LASIK vision correction procedure takes 10-15 minutes per eye and is virtually painless. Recovery is exceptionally quick – you will notice an improvement immediately and patients can experience full visual improvement in one to four weeks. While LASIK results vary between individuals, most patients achieve better than 20/20 vision, spectacle liberation and a new, frameless perspective on the world around them. A post-op follow-up visit to check the healing process is scheduled for the day after treatment.
LASIK is the most common laser vision correction procedure performed today with outstanding results for patients.
There are several necessary preparations in the preoperative period. The operation itself involves creating a thin flap on the eye, folding it to enable remodelling of the tissue beneath with a laser. The flap is repositioned and the eye is left to heal in the postoperative period.
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.
The operation is performed with the patient awake and mobile; however, the patient is sometimes given a mild sedative (such as Valium) and anaesthetic eye drops.
LASIK is performed in three steps. The first step is to create a flap of corneal tissue. The second step is remodelling of the cornea underneath the flap with the laser. Finally, the flap is repositioned.
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 haemorrhage 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.
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.
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.
Post-op Visual Recovery and Comfort
Patients can resume most activities on the day following surgery. This is because the smoothness of the corneal surface is minimally disrupted by the surgery. You may be required to wear a protective shield over your eyes for the first night or two following the procedure. Your doctor may also instruct you to take antibiotic, anti-inflammatory, or moistening eye drops, and to wear dark eyeglasses if you experience sensitivity to bright lights. After LASIK surgery, you should lie down, relax, and close your eyes. Watching television, reading, or operating a computer should be avoided for the first 24 hours. The LASIK surgery recovery process requires your eyes to remain relaxed.
Do not rub your eyes. Some patients report a mild burning sensation two to four hours into LASIK surgery recovery as the anaesthetic wears off. The sensation resembles wearing an itchy or dirty contact lens.
Wear sunglasses after surgery – rain or shine. Take baths instead of showers for the first 24 hours after surgery and be careful not to allow the shower to spray directly into your face for the first week. Use a face cloth and be careful not to rub your eyes. Avoid eye makeup and smoky or dusty environments for a week. Avoid alcohol consumption for 48 hours after LASIK surgery.
Post-op Stabilisation of Prescription
The eye tends to stabilise at around one month, which is quicker than with the other laser techniques. This is because the healing response is relatively mild after LASIK. Therefore, regression of the prescription is less likely to occur following LASIK surgery compared to other techniques, particularly for treatment of high prescriptions.
Post-op Corneal Haze
Virtually no corneal haze is observed after LASIK surgery.
After LASIK: Longer Term
With LASIK surgery, most people's vision improves right away, but some find that their vision gradually improves even more over the next few days or even weeks.
Most people achieve 20/20 or better vision with LASIK. Some may achieve only 20/40 or not quite as good. In fact, 20/40 is fairly good vision. Some patients may still need glasses or contact lenses following laser vision correction, though their prescription level typically will be much lower than before.
General LASIK Requirements
Your ophthalmologist will follow these guidelines when considering your candidacy for LASIK. For safe laser eye surgery, the LASIK candidate must meet the following requirements:
- Ensure that the eye has developed properly and matured, the ideal LASIK candidate is at least 18 years old.
- Prior to surgery, vision must be stable for at least one year.
- No eye infection or injury within the past year.
- Candidates may not be affected by an autoimmune disorder, such as Sjogren's Syndrome or Lupus.
- No history of herpes infections in the eye, as LASIK may bring on a recurrence of the infection.
- No scarring may be present on the cornea to be considered for LASIK.
- Candidates must understand the risks of LASIK surgery and have realistic expectations regarding the results that can be achieved.
- A LASIK candidate may not be nursing or pregnant on the date of surgery.
- Individuals with dry eye syndrome are not good LASIK candidates.
- Individuals with pupils that dilate beyond seven millimetres in the dark are not good candidates for LASIK.
Pre-LASIK Eye Examination
Prior to LASIK vision correction surgery, your LASIK surgeon will perform a comprehensive eye exam to ensure that you are a good candidate for treatment. During this exam, a map of your eye will be created. This map will be used during the LASIK procedure so a precise amount of corneal tissue is removed, providing you with the clearest visual results possible. The pre-LASIK vision correction evaluation should include:
- Dilated exam to check for ocular irregularities
- Refractive error measurement
- Pupil and corneal thickness measurements
- Corneal topography map
- Tear function analysis
- Discussion of medical history, lifestyle, and expectations
This evaluation determines if the patient’s eye curvature is suitable for the LASIK procedure. If not, the surgery could result in tear problems or unstable vision. Additionally, the evaluation measures tear production. The eyes naturally produce fewer tears as we age and LASIK always causes temporary dryness. If a prospective patient has naturally dry eyes, LASIK vision correction may not a suitable option.
Tips – Preparing for LASIK Vision Correction
After determining whether a patient is a good candidate for LASIK vision correction, the ophthalmologist will thoroughly discuss LASIK benefits and possible LASIK complications. Your laser eye surgeon will then review an individualized treatment plan, including what to do in the days and weeks prior to LASIK vision correction.
Generally, patients should follow the guidelines below:
The Weeks Prior to LASIK Surgery
Contact lenses should not be worn in the weeks prior to LASIK vision correction surgery. This is because the success of LASIK is dependent on accurately measuring the shape and curvature of your cornea, which can be affected by lenses. A period of time without contacts restores your cornea to its natural shape. The Food and Drug Administration (FDA) recommends that LASIK patients adhere to the following guidelines:
Soft contact lenses should not be worn for at least two weeks prior to LASIK vision correction surgery.
Gas permeable contact lenses should not be worn for at least three weeks prior to LASIK vision correction surgery.
Hard contact lenses should not be worn for at least four weeks prior to LASIK vision correction surgery.
Following these standards will ensure that your refractive error is measured properly, resulting in an optimal LASIK surgery recovery period and superior vision correction.
The Day Before LASIK Surgery
On the day before LASIK vision correction surgery, patients should stop using any makeup, lotions, perfumes, or creams that may cause debris to get into the eye. LASIK eye surgeons may request patients thoroughly wash their eyes to prevent any chance of infection.
The Day of LASIK Surgery
On the day of your LASIK vision correction surgery, eat a light meal before going to the eye surgeon and take any doctor-prescribed medications as normal. Do not wear any makeup or lotion, as they may increase the likelihood of infection. Also, do not wear any bulky accessories in your hair that may interfere with positioning your head under the laser. Patients’ eyes will be measured again before surgery and the LASIK surgeon will once again go through the procedure, making sure you have no additional questions or concerns. An anaesthetic and any needed anti-anxiety medication will then be administered.
Common Fears Associated with LASIK Surgery
Fear of Pain
One of the most common fears about the surgery is LASIK pain. Many prospective LASIK patients are afraid they will experience some kind of discomfort since the procedure is performed while they are fully conscious. However, a mild sedative is given to patients to ensure that they remain comfortable, and numbing drops are applied to the eyes before the surgery begins. Although patients may feel some pressure, these steps help to make the LASIK process relatively pain free.
Fear of Laser Contact
Aside from LASIK pain, many prospective patients are also afraid of having a laser beam shine directly into their eyes during the procedure. While LASIK surgery does involve the use of a laser to remove tissue from the cornea, the laser only comes in contact with each eye for about 10-to-15 seconds. Some patients are concerned they might blink or look away during surgery and fear that this might result in serious complications. However, the laser used during LASIK has an eye tracking system which follows eye movement, and laser pulses are matched to that movement during treatment.
Fear of "the Scalpel"
Some patients are also afraid that a scalpel will be used to make a flap in the cornea during LASIK surgery. However, the LASIK process does not incorporate the use of a scalpel. Instead, a microkeratome blade or an IntraLase® laser is used during the procedure to create the corneal flap.
Fear of Going Blind as a Result of LASIK Surgery
In addition to LASIK pain, another common fear patients have is that they might go blind after LASIK surgery. But according to the FDA, there have been no reported cases of a patient going blind due to LASIK. In fact, the risk of facing serious complications after surgery is less than 1 percent, and the risk of suffering from less serious complications is 3 percent. It is also very rare for a patient’s vision to become worse after LASIK surgery. Should that occur, your surgeon will perform a second procedure to correct the problem.
Fear of Being Awake During the Procedure
Prospective LASIK patients may also be worried about having to be awake during surgery. Although patients must be awake during the LASIK procedure, they are given a mild sedative beforehand to help them relax.
Fear of the Eyes Being Open During the Procedure
Even though a sedative is administered to help patients calm down before surgery, some patients are still fearful of having to watch the entire LASIK procedure. However, the surgeon applies drops to the eyes during LASIK surgery, which allows the patient’s vision to black out for about ten seconds. Because of this, the patient will not be able to see the entire procedure.