LASIK Risks
What are the Risks of LASIK surgery?
The risks of LASIK fall into two main categories: Vision Loss Risks, and Nuisance Risks.
Vision Loss Risks
Loss of vision after LASIK surgery is very rare. When vision is lost in an otherwise uncomplicated LASIK procedure, it typically is 1 or less lines on the eye chart of best corrected vision even with extra help from glasses. As such, LASIK surgery has a very good safety profile. There are two possible ways vision could be lost to a more severe degree:
- Infection: Since cuts are made on the eye it is possible that bacteria could gain access to the corneal tissue and cause an infection. Scarring from infection could lead to vision loss; however, because of the powerful antibiotics administered after surgery this is very uncommon. The risk of severe infection is less than 1 in 500.
- Progressive Corneal Warpage (Ectasia): In this condition, the cornea begins to warp in odd directions causing loss of vision. Occasionally, a corneal transplant is required to fix this condition. Ectasia is typically only seen in patients with abnormal corneal shapes or corneal dystrophies, such as keratoconus, that exist before the surgery. Your surgeon will screen your corneas very closely to help identify any preexisting corneal shape irregularity. The risk of ectasia is less than 1 in 3,500.
Nuisance Risks
Most of the other risks associated with LASIK surgery will not cause significant loss of vision. Instead they may cause nuisance problems with the eyes that may not have been present before the surgery.
- Dry Eye: Almost everyone undergoing LASIK has some mild dryness, in which the eyes feel scratchy. Typically, these symptoms resolve after a few months; however a small percentage of people experience chronically worse dry eyes after LASIK. This may require continuous treatment with drops or dry eye medications.
- Night Vision Symptoms: Some patients notice their night vision after LASIK surgery is different than before. Usually, this occurs in the form of halos around streetlights, added glare from oncoming traffic, or increased difficulty seeing dimly light shapes in the dark. Typically, these symptoms improve with time.
Data from several studies has shown that if 100 patients had such symptoms at 1 month after surgery, only 20 to 30 will still have symptoms by 1 year. Some surgeons believe that a larger pupil size may put a patient at increased risk for night vision problems. However, such complaints can still happen in people with small pupil sizes. Most people with night vision complaints find them only mildly annoying. However, a few individuals may feel that they are unable to function well in low light settings. Medications can be used to change the size of the pupil in low light or nighttime settings, which can help reduce night vision symptoms from LASIK if they occur.
- Flap complications: Although rare, it's possible a flap is created with an irregular edge or a buttonhole in the center. If this occurs the surgeon will replace the flap on the eye and cancel surgery until the eye heals. Little, if any, vision is lost in such a complication; however, it may take several months for the eye to fully heal. Surface laser, such as PRK, may still be an option for LVC after several months.
- The LASIK flap may become dislodged or wrinkled before it is fully healed. If this occurs your surgeon will do a minor procedure to put it back in place, usually with no loss of vision.
- Cells from the surface of the eye may grow under the LASIK flap this is called epithelial in-growth. Although rare in primary LASIK procedures, epithelial in-growths are more common in LASIK enhancements. Epithelial in-growths often resolve on their own, although it's possible that the surgeon will need to lift the flap and remove the cells in order to maintain excellent uncorrected vision.
- In the first few days after the surgery the eye sometimes tries to heal the LASIK wound too aggressively which sends too many white blood cells to the cornea. This condition, Diffuse Lamellar Keratitis (DLK), can be resolved with frequent steroid eye drops.
- Enhancements: Even though the excimer laser is extremely precise the fact that the eye is a living tissue and individual healing response varies means that it's possible for LASIK surgery to over or under-correct refractive error. If this happens a "touch up" LASIK procedure or enhancement is done several months later to correct the remaining refractive error. Enhancement procedures carry a small risk of all of the above complications, just like the original LASIK procedure. About 5-10% of patients who undergo LASIK will require an enhancement procedure to obtain their vision goals.
