Lasik Risks, Side Effects & Complications

As with any kind of surgical procedures, there are benefits as well as possible risks of refractive eye surgeries like LASIK done to your eyesight. You should therefore, carefully consider all the aspects of the risks LASIK eye surgery or any other refractive eye surgeries, before making a decision.

To make this informed decision, you’ll need to learn the facts about LASIK eye surgery. You’ll have to understand how the eye works and learn pertinent details about the cornea. After which, you should take time to look for a good eye surgeon.

While refractive surgery is becoming more affordable and safe, it is not for everybody. People who are slow healers or who have ongoing medical conditions such as glaucoma or diabetes, uncontrolled vascular disease, autoimmune disease, pregnant women or people with certain eye diseases involving the cornea or retina, are not good candidates for refractive surgery. Furthermore, some people's eye shape may not permit effective refractive surgery without removing dangerous amounts of corneal tissue. It is important that those considering laser eye surgery have a full examination. Unfortunately, since some surgeons eager to find business may accept patients unsuited to such surgery, prospective patients should choose their surgeon with care.

Common risks/complications even for healthy people may be:

- Infection and delayed healing: There is a less than 0.1 percent chance of the cornea becoming infected after PRK, and a somewhat smaller chance after LASIK. This is uncomfortable, but has no long-term effects after a period of four years.

- Undercorrection/Overcorrection  : Predicting perfectly how your eye will respond to laser surgery is not yet possible. Therefore, you may still need corrective lenses after the procedure to obtain good vision. In some cases, a second procedure can be done to improve the result.

- Decrease in Best-Corrected Vision: After refractive surgery, a few patients find that their best obtainable vision with corrective lenses is worse than it was before the surgery. This may happen as a result of irregular tissue removal or the development of corneal haze.

- Excessive Corneal Haze: Corneal haze occurs as part of the normal healing process after PRK. In all but a few cases, it has no effect on the final vision and can only be seen by an eye doctor with a microscope. However, there are some cases of excessive haze that interferes with vision. As with undercorrections, this can often be dealt with by means of an additional laser treatment. The risk of significant haze is much less with LASIK than with PRK.

- Regression: In some patients the effect of refractive surgery is gradually lost over several months. This is like an undercorrection, and a re-treatment is often feasible. But, usually results are permanent.

- Halo and Glare Effect: The halo & glare effect is an optical effect that is noticed in dim light. When the pupil enlarges to adapt to the dimmer light, a second faded image is produced by the untreated peripheral cornea. For some patients who have undergone PRK or LASIK, this can interfere with night driving.

- Epithelial ingrowth: This is a post-operative complication where epithelial cells grow between the flap and the stroma during healing of the flap incision. This may appear any time in the first several months post-operatively.

- Flap Damage or Loss (LASIK only): Instead of creating a hinged flap of tissue on the central cornea, the entire flap could come loose. If this were to occur it could be replaced after the laser treatment. However, there is a risk that the flap could be damaged or lost.

- Distorted Flap (LASIK only): Irregular healing of the corneal flap could create a distorted corneal shape, which would decrease the best-corrected vision.

- Dry eye: Feeling of dryness, soreness, and discomfort in the eye.

- Altitude effects: Some refractive surgery patients have reported significant changes in vision with changes of altitude (perhaps because oxygen concentration can affect corneal swelling). A patient who achieves good vision at sea level may have poorer results in the mountains.

- Incomplete Procedure: Equipment malfunction may require the procedure to be stopped before completion. This is a more important factor in LASIK, due to its higher degree of complexity, than in PRK.

Survey

According to CRSQA (an industry body concerned with quality control of ocular surgery), a competent refractive surgeon will typically achieve results at the following levels:

Around 90% of patients will receive 20/40 or better uncorrected visual acuity (and, thus, 10% will not).
Around 50% will achieve 20/20 or better (and 50% will not); patients with high myopia, hyperopia, or astigmatism, have poorer chances of achieving 20/20.
Around 10% of patients will need retreatment
"Less than 3%" of patients will have unresolved complications six months after surgery.

Reference