Some patients with poor outcomes from LASIK surgical
procedures report a significantly reduced quality of life because of
vision problems or physical pain associated with the surgery.
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.
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
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." Consequently, 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 most common complication from refractive surgery is the incidence of "dry eyes." According to an American Journal of Ophthalmology study of March 2006, the incidence rate of dry eyes from LASIK after the six month post operative healing period was 36%. The FDA (Food and Drugs Administration) website states that "dry eyes" may be permanent.
The high incidence of dry eyes necessitates a proper preoperative and post operative evaluation and treatment for dry eyes.
There are a number of successful treatments for dry eyes including artificial tears, prescription tears and punctal occlusion.
Punctal occlusion is accomplished by placing a collagen plug in the natural drain of the eye. Dry eyes, if left untreated can compromise the visual outcome and result in regression of the effect of LASIK or PRK, or in severe cases result in "chronic dry eye" where permanent chronic pain and visual impairment is a possible outcome.
It also must be noted that some incidences of dry eye cannot be successfully mitigated using the above mentioned techniques, so a potential lasik patient must consider that dry eye can be a permanent outcome and untreatable.
The risk for a patient of suffering from disturbing visual side effects such as halos, double vision (ghosting), loss of contrast sensitivity (foggy vision) and glare after LASIK depends on the degree of ametropia before the laser eye surgery and other risk factors.
For this reason, it is important to take into account the individual risk potential of a patient and not just the average probability for all patients.
The following are some of the more frequently reported complications of LASIK:
- Surgery induced dry eyes
- Overcorrection or undercorrection
- Very Low level vitamin D - Sun sensitivity
- Visual acuity fluctuation
- Halos or starbursts around light sources at night
- Light sensitivity
- Ghost images 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:
- The incidence of flap complications has been estimated to be 0.244%. Flap complications (such as displaced flaps or folds in the flaps that necessitate repositioning, diffuse lamellar keratitis, and epithelial ingrowth) 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. According to proponents of such techniques, this risk is further reduced by the use of IntraLasik and other non-microkeratome related approaches, although this is not proven and carries its own set of risks of complications from the IntraLasik procedure.
- 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. Patients are usually given sleep goggles or eye shields to wear for several nights to prevent them from dislodging the flap in their sleep. 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..
- The incidence of diffuse lamellar keratitis (DLK), also known as the Sands of Sahara syndrome, has been estimated at 2.3%. DLK is an inflammatory process that involves an accumulation of white blood cells at the interface between the LASIK flap and the underlying corneal stroma. It is most commonly treated with steroid eye drops, and sometimes it is necessary for the eye surgeon to lift the flap and manually remove the accumulated cells.
- The incidence of infection responsive to treatment has been estimated at 0.4%. 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.
- The incidence of subconjunctival hemorrhage has been estimated at 10.5%
- 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.
- Dry eye or in severe cases Chronic Dry eye. Due to nerves that are severed during the Lasik operation (around 70% of corneal nerves are severed), the lubrication system of the eye is affected and nerves may never recover to pre-operative condition. This may leave the patient with potential permanent dry eyes.
Lasik and other forms of laser refractive surgery (i.e. PRK, LASEK and Epi-LASEK) change the dynamics of the cornea. These changes make it difficult for your optometrist and ophthalmologist to accurately measure your intraocular pressure, essential in glaucoma screening and treatment.
The changes also affect the calculations used to select the correct intraocular lens implant when you have cataract surgery. This is known to ophthalmologists as "refractive surprise." The correct intraocular pressure and intraocular lens power can be calculated if you can provide your eye care professional with your preoperative, operative and postoperative eye measurements.
Although there have been improvements in LASIK technology, a large body of conclusive evidence on the chances of long-term complications is not yet established. Also, there is a small chance of complications, such as haziness, halo, or glare, some of which may be irreversible because the LASIK eye surgery procedure is irreversible.
The incidence of macular hole has been estimated at 0.2 percent The incidence of retinal detachment has been estimated at 0.36 percent.
Although the cornea usually is thinner after LASIK, because of the removal of part of the stroma, refractive surgeons strive to maintain the maximum thickness to avoid structurally weakening the cornea.
Decreased atmospheric pressure at higher altitudes has not been demonstrated as extremely dangerous to the eyes of LASIK patients. However, some mountain climbers have experienced a myopic shift at extreme altitudes.
In situ keratomileusis effected at a later age increases the incidence of corneal higher-order wavefront aberrations. Conventional eyeglasses do not correct higher order aberrations.
Microfolding has been reported as "an almost unavoidable complication of LASIK" whose "clinical significance appears negligible."
Factors affecting surgery
Typically, the cornea is avascular because it must be transparent to function normally, and its cells absorb oxygen from the tear film. Thus, low-oxygen-permeable contact lenses reduce the cornea's oxygen absorption, sometimes resulting in corneal neovascularization—the growth of blood vessels into the cornea. This causes a slight lengthening of inflammation duration and healing time and some pain during surgery, because of greater bleeding.
Although some contact lenses (notably modern RGP and soft silicone hydrogel lenses) are made of materials with greater oxygen permeability that help reduce the risk of corneal neovascularization, patients considering LASIK are warned to avoid over-wearing their contact lenses. Usually, it is recommended that they discontinue wearing contact lenses days or weeks before the LASIK eye surgery.
New advances in eyesight corrective surgery are providing consumers greater choices. Patients in their 40s or 50s who are considering LASIK surgery to improve their vision might want to consider to be evaluated for implantable lenses as well. "Early signs of a cataract might argue for surgery and implantation of multifocal lenses instead."
The FDA has approved LASIK for age 18 and over. More importantly the person's eye prescription needs to be stable for at least one year prior to surgery.
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