What is LASIK
Lasik, an acronym for Laser Assisted in Situ Keratomeleusis, is a form of refractive laser eye surgery procedure performed by ophtalmologists intended for correcting Myopia, Hyperopia and Astigmatism. The procedure is usually a preferred alternative to photorefractive keratectomy, PRK, as it requires less time for full recovery and the patient experiences less pain overall.
Wavefront-guided LASIK is a variation of LASIK surgery where, rather than apply a simple correction of focusing power to the cornea (as in traditional LASIK), an ophthalmologist applies a spatially varying correction, guiding the computer-controlled eximer 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 exceed any benefit from wavefront correction. Hence, patients expecting so-called "super vision" from such procedures may be disappointed. However, while unproven, 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.
What is the procedure
Patients wearing soft contact lenses typically are instructed to stop wearing them approximately 10 to 14 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 had 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 locations of corneal tissue to be removed during the operation. The patient typically is prescribed an antibiotic to start taking beforehand, to minimize the risk of infection after the procedure.
The operation is performed with the patient awake and mobile; however, the patient typically is given a mild sedative (such as Valium) and anesthetic eye drops.
LASIK is performed in two steps. The first step is to create a flap of corneal tissue. A corneal suction ring is applied to the eye, holding the eye in place. The 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 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 adjacent stroma by releasing the molecular bonds that hold the cells together. No burning with heat or actual cutting is required to ablate the tissue. The layers of tissue removed are tens of micrometers thick. Performing the laser ablation in the deeper corneal stroma typically provides for more rapid visual recovery and less pain.
During the second step, the patient's vision will become very blurry once the flap is lifted. He/she will be able to see only white light surrounding the orange light of the laser. This can be disorienting.
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. The energy of each pulse is usually in the milliwatt range. Typically, each pulse is on the order of 10–20 nanoseconds. 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 discontinued in the weeks following surgery. Patients are also given a darkened pair of goggles to protect their eyes from bright lights and protective shields to prevent rubbing of the eyes when asleep.
What are the complications
A subconjunctival hemorrhage is a common and minor post-LASIK complication. The incidence of subconjunctival hemorrhage has been estimated at 10.5%. The following are some of the more frequently reported complications of LASIK:
- Dry eyes
- Overcorrection or undercorrection
- Visual acuity fluctuation
- Halos or starbursts around light sources at night
- Light sensitivity
- Ghosts or double vision
- Wrinkles in flap (striae)
- Decentered ablation
- Debris or growth under flap
- Thin or buttonhole flap
- Induced astigmatism
- Corneal Ectasia
- Epithelium erosion
- Posterior vitreous detachment
- Macular hole
Complications due to LASIK have been classified as those that occur due to preoperative, intraoperative, early postoperative, or late postoperative sources:
Flap complications (such as displaced flaps or folds in the flaps that necessitate repositioning, diffuse lamellar keratitis, and epithelial in-growth) are common in lamellar corneal surgeries but rarely lead to permanent visual acuity loss; the incidence of these microkeratome-related complications decreases with increased physician experience. This risk is further reduced by the use of IntraLasik and other non-microkeratome related approaches.
A slipped flap (a corneal flap that detaches from the rest of the cornea) is one of the most common complications. The chances of this are greatest immediately after surgery, so patients typically are advised to go home and sleep to let the flap heal. A faster operation may decrease the chance of this complication, as there is less time for the flap to dry.
Flap interface particles are another finding whose clinical significance is undetermined. A Finnish study found that particles of various sizes and reflectivity were clinically visible in 38.7% of eyes examined via slit lamp biomicroscopy, but apparent in 100% of eyes using confocal microscopy.
Early postoperative complications
Diffuse lamellar keratitis (DLK), also known as the Sands of Sahara syndrome, when diagnosed and appropriately treated, resolves with no lasting vision limitation.
Infection under the corneal flap is also possible. It is also possible that a patient has keratoconus that causes the cornea to thin after surgery. Although this condition is screened in the preoperative exam, it is possible in rare cases (about 1 in 5,000) for the condition to remain dormant until later in life (the mid-40s). If this occurs, the patient may need rigid gas permeable contact lenses, Intrastromal Corneal Ring Segments (Intacs), Corneal Collagen Crosslinking with Riboflavin or a corneal transplant.
The incidence of persistent dry eye has been estimated to be as high as 28% in Asian eyes and 5% in Caucasian eyes. Nerve fibers in the cornea are important for stimulating tear production. A year after LASIK, subbasal nerve fiber bundles remain reduced by more than half. Some patients experience reactive tearing, in part to compensate for chronic decreased basal wetting tear production.
Late postoperative complications
The incidence of epithelial ingrowth is very low
Glare is another commonly reported complication of those who have had LASIK.
Halos or starbursts around bright lights at night are caused by the irregularity between the lasered part and the untouched part. It is not practical to perform the surgery so that it covers the width of the pupil at full dilation at night, and the pupil may expand so that light passes through the edge of the flap into the pupil. In daytime, the pupil is smaller than the edge. Modern equipment is better suited to treat those with large pupils, and responsible physicians will check for them during examination.
Late traumatic flap dislocations have been reported 1–7 years post-LASIK.
Although there have been a number of improvements in LASIK technology, a large body of conclusive evidence on the chances of long-term complications is not yet in place. Also, there is a small chance of complications, such as slipped flap, corneal infection, haziness, halo, or glare. The procedure is irreversible.
The following incidents do occur but are rare:
- macular hole
- retinal detachment
- choroidal neovascularization
Although the cornea usually is thinner after LASIK because of the removal of part of the stroma, refractive surgeons strive to maintain a minimum thickness in order to not structurally weaken the cornea. Decreased atmospheric pressure at higher altitudes has not been shown to be extremely dangerous to the eyes of LASIK patients. However, some mountain climbers have experienced a myopic shift at extreme altitudes. There are no published reports documenting diving-related complications after LASIK.
Laser in situ keratomileusis increases higher order wavefront aberrations of the cornea. Glasses do not correct higher order aberrations.
Microfolding has been reported as "an almost unavoidable complication of LASIK" whose "clinical significance appears negligible".
Persons who are myopic (near sighted) and are close to the age where they will need reading glasses or bifocals (usually in the mid to late 40 years of age), may find that they need reading glasses after having refractive surgery, such as LASIK. People with myopia generally require reading glasses or bifocals at a later age than people with are emmetropic (people who can see clearly without glasses) but this benefit is lost if Lasik is performed. This is not a complication but an expected result of the physical laws of optics.
How safe is LASIK
In 2003, the Medical Defence Union (MDU), the largest insurer for doctors in the United Kingdom, reported a 166% 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% of treated patients and 12% 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 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."
You hear all the benefits and you are eager to get rid of this deminishing sight. It all seems an easy solution with very little risk. However you are not told everything. One of the pioneers of LASIK himself has stopped performing LASIK:
A Taiwanese surgeon who was a pioneer in the field of Lasik eye surgery has ceased perforiming LASIK, as it violates his medical ethics.
Ophthalmologist Ray Tsai, who conducted groundbreaking trials with patients at Chang Geng Memorial Hospital in Linkou, Taiwan in the 1990's, claims to have met around 10 patients who have experienced sudden vision loss years after receiving Lasik surgery.
Tsai says the patients are usually between 40 to 50 years of age, and suggests their post-operative vision loss is linked to corneal inflammation resulting from the LASIK procedure.
"It is against my ethics to not tell [patients] all the possible consequences," Tsai announced on Tuesday. "After a full consideration, I decided to quit Lasik."
Experience with Lasik
Letter from a patient:
Here is a list of the people I have encountered with LASIK complications since my surgery a number of months ago:
1. A young man (mid 20'S) sitting in my surgeon's waiting room with me also had large pupils and has severe night vision starbursts and halos from LASIK. For him, the TV screen has huge smeary ghosts extending beyond the set itself. The night vision complications are a problem since he must travel a great deal at night for his job.
2. In the office of one of my 2nd opinion docs I met a young woman who had LASIK resulting in blurry vision in one eye and double vision in the other. A young mother and a real shame.
3. A technician in the office above, sporting a button that said "Ask me about my LASIK" was blinking uncomfortably from dry eye because she had taken a cold tablet. She admitted that she was eyedrop dependent. And only in her twenties... what will happen to her as her eyes dry naturally with age?
4. I went to an optometrist for glasses. He is only in his 30s but has dry eye from LASIK and must wear lower plugs. Since when do young males have dry eye? Can you say "LASIK CORNEAL NERVE DAMAGE"?
5. My dental hygienist is uncomfortable driving at night after her LASIK.
6. I went to a hair salon for a cut. The proprietor has a sagging eyelid from LASIK and dry eye for which she has been cauterized - and she takes the expensive Restasis eye drop regimen. She reports loss of contrast sensitivity and night vision problems. She had double vision for a while, luckily that went away.
7. Same salon, an employee had LASIK and has dry eye.
8. A sales rep I deal with often is married to a man who had a horrific post-LASIK visual and dry eye experience. They took me out to lunch to tell me about it. He still has blurry vision in one eye and has plugs. He is in his mid 30's. He said the psychological strain of the problem nearly pushed him over the edge.
9. A man in the building across the street from where I work had a bad LASIK with blurry vision at all distances. He claimed that he was misled by the practice. "What they tell you before [surgery] and what they tell you after are two different things" he said. I can second that, because my surgery was at the same practice, same surgeon.
Although many patients have reported being satisfied with the outcome of the procedure of Lasik, what is not told is the consequences that people experience when Lasik is not successful.Various patients with poor outcomes from LASIK procedures report that they have significantly reduced quality of life due to vision problems, and have expressed concerns over the way that LASIK is marketed to potential patients. Patients who have suffered LASIK complications have published websites in an effort to educate the public about the risks, and to provide forums where prospective and past patients can discuss the surgery.
Some of the best sites are:
A great forum where you can read and share experience and questions: www.lasikflap.com/forum
The alternative to Lasik surgery
As you have read Lasik surgery is very expensive and risky. The more reason to try an alternative method that is successful, affordable and natural: Eyerobics.
Lasik surgery is aimed to address myopia (nearsightedness), hyperopia (farsightedness) or astigmatism. These are the very disorders that have the highest success rate of all common disorders addressed by the natural vision improvement program Eyerobics.
Lasik surgery does NOT address the underlying cause of the problem but merely alters a part of your body to create a quick fix. The motivation for this shortsighted approach is the same as it is for most allopathic forms of treatment: We do not suffer from a disease or disorder itself, but from the symptoms, therefore the approach to get rid of the symptoms is logical and results in some satisfaction even though this fix is often short lived. This principle also applies to wearing glasses or lenses. Wearing them allows people to see clearer again, but most of the times results in a further deterioration of your eyes as they do no longer get the exercise to stay in shape because your glasses do all the focusing.
If you get weaker leg muscles because you do not exercise enough would you consider buying a wheelchair or would going to the gym be a better alternative? The same counts for your eyes. Hyoperopia, myopia and astigmatism are often caused by not using your eyes well. In today's society we often stress our eyes too much and do not give them the right relaxing exercise.
As your eye muscles control your ability to focus it makes sense to start with improving their ability and well-being when trying to improve your eyesight, NOT by cutting things of your eyes or creating scar tissue by burning parts of your eyes via Lasik surgery.
"After four eye operations, 25 years in glasses and contact lenses, and still having problems I discovered Eyerobics.
In 2 weeks I started getting results and such clear vision that I removed my contact lenses and have never used them since. I made a visit to my eye specialist in Melbourne. I wanted an unbiased opinion so I didn't mention what I had been doing.
After he examined me, he told me my eyes were great and I wouldn't need glasses or contacts again. I couldn't be happier with the results, so simple and yet noticing each day the major improvements."
Tracey McIvor - Euroa, Victoria.