Complications of Laser Surgery
Complications and risks are an inherent part of any surgery despite advanced technology and skilled professionals involved in the process. Although there is a small possibility of a serious vision complication because of laser surgery it is important to know these risks in order to make an informed decision regarding the procedure. Remember the goal of laser surgery is not necessarily to eliminate the need for corrective eyewear but to reduce a patient's dependence on it. The following categories are a breakdown of the various surgical complications.
Refractive complications include under-correction over-correction and a prescription imbalance between eyes. This can result in leaving patients nearsighted farsighted or with astigmatism. These problems are due to the unpredictability in patient healing patterns as every eye heals differently. It is more common in patients with strong prescriptions. For example a myopic patient with a strong prescription who under heals by 10% will have a residual level of nearsightedness that would still require correction by glasses or contact lenses.
The greatest risk of infection occurs within the first few days following the procedure although minor infections cure quickly. In most cases your surgeon will give you antibiotic drops to use before and after the procedure as a preventative measure.
Regression refers to the tendency of the eye to return to its original prescription after the procedure. When this occurs some laser surgery centres offer complementary enhancement procedures but you should inquire about this practice before you finalize your choice of surgeons. In the majority of cases regression is minimal and surgeons account for it when planning the procedure. Alternatives to enhancement procedures - when surgeons do not advise it or patients are reluctant to undergo another surgery - include glasses or contact lenses.
Poor Night Vision
Many people experience halos or night glare to a certain degree even if they have not undergone laser surgery. For a few months after such a procedure most patients experience temporary glare and halos which is normal. If the glare and halos persist however it is due to a refractory error. In this case patients may require corrective eyewear or a surgical enhancement procedure to remedy the problem.
Dry eye is common following laser surgery and the procedure often exacerbates the problem. The procedure severs some of the moisture-sensing corneal nerves. Dry eye will occur until these nerves re-establish themselves. A low percentage of patients experience long-term irritating dryness but artificial tears and ointments help most cases.
Loss of Best Corrected Vision
Some patients experience a slight loss of visual crispness following laser surgery as compared to the vision they previously had using corrective eyewear. In some cases the sharpness returns after a few months but in others vision is not as clear as before surgery even with corrective eyewear.
LASIK and Corneal Flap Complications
Complications can occur due to the size thickness and positioning of the corneal flap. They range in severity from those that simply require postponing the LASIK procedure by a few months to those that require an additional surgical procedure. At the severe end of the spectrum sometimes there are permanent corneal irregularities and blurred vision. This includes corneal perforations which have been reported a few dozen times worldwide or wrinkles or folds in the flap.
Epithelial in-growth occurs during the first month following LASIK and is more likely to occur in patients with an abnormal or weakly adherent protective layer for which age is a factor. This is a common condition and in most cases it does not present any symptoms and does not require treatment. Epithelial in-growth is produced when epithelial surface cells grow underneath the corneal flap during the healing of the corneal flap incision. Epithelial in-growth is more common with any trauma or breakdown of the epithelium which is more common in LASIK enhancement procedures and long-term contact lens wearers. Treatment of this condition involves lifting the flap and clearing the cells away. Although most small areas of epithelial in-growth need only be monitored untreated large areas of epithelial in-growth may distort vision and may actually damage the flap integrity if severe and progressive.
Diffuse Lamellar Kerititis (DLK or Sands of the Sahara)
DLK is a unique post-operative complication associated with the LASIK procedure. It results from a sterile-inflammatory response from creating the corneal flap. Non-severe forms of DLK occur in an estimated 1% of LASIK patients while severe forms occur in 1 out of 5000 patients.
Doctors recommend that patients abide by the post-operative follow-up schedule set out by their surgeon as most cases of DLK are detectable before visual disturbances arise. The treatment is easy when detected early. It may take up to a few months however for complete resolution of the inflammation. Severe cases of DLK might not respond to conventional therapies and might require surgical lifting of the flap and a thorough irrigation of the interface with saline solution.
You will not have any pain or discomfort during the laser procedure itself. With new techniques a relatively small number of patients experience discomfort following the procedure which can usually be treated with medication. Most patients experience some irritation sensitivity to light and watering or swelling of their eyes for a few days following the procedure.
It is important to note that the chance of having a serious vision-threatening complication is much less than 1%. In general most of the risks following the LASIK and PRK procedures are the same. However while LASIK does offer a faster and easier visual recovery it also has specific risks due to the creation of the corneal flap.