Evidence Based

LASIK Complications & Risks

Is LASIK Dangerous?

In modern LASIK eye surgery, serious complications are rare. Several large studies have demonstrated LASIK complication rates of less than 1 to 1.8 percent. However, there are some potential problems to know if you are considering LASIK.

LASIK, which stands for laser-assisted in situ keratomileusis, is a refractive eye surgery. This procedure can correct astigmatism, nearsightedness (myopia), and farsightedness (hyperopia). 

Also, not everyone is a good candidate for LASIK. If you have any of the following medical conditions, laser eye surgery is likely not an option:

  • Degenerative conditions
  • Sjogren's syndrome
  • Type 1 diabetes
  • AID (people with HIV who are in good health may be good candidates for LASIK)
  • Uncontrollable autoimmune diseases
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Lower Risk Complications of LASIK

Common complications of LASIK surgery that are low risk include:

Overcorrection or Undercorrection 

This means your vision is not entirely corrected. However, having a small overcorrection or undercorrection is not uncommon. If you are satisfied with your vision and can see clearly, retreatment is not necessary.

However, if you are not happy with your vision, the surgeon may be able to retreat you or prescribe glasses and contacts to correct your vision.

Regression 

Regression occurs when your vision worsens after receiving LASIK. Regression is related to changes in your eye, such as your natural lens or the length of your eyeball.

Only 1 to 2 percent of patients require an enhancement procedure during the first year after LASIK. Studies show that about 10 percent of patients experience some regression after ten years. Also, keep in mind that normal age-related changes may affect your vision.

Irregular Astigmatism 

Irregular astigmatism is an unequal curvature of your cornea, which causes visual distortion. Common symptoms include glare, halos, starbursts, and ghosting or shadows around images. A second procedure may be necessary to correct irregular astigmatism.

Decentration 

Decentration is when the laser is not centered correctly on the eye during surgery. This can cause irregular astigmatism and may require retreatment. There is a higher risk of this complication with traditional microkeratome LASIK than with bladeless LASIK.

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Higher Risk Complications of LASIK

Higher risk complications of LASIK eye surgery include:

Epithelial Ingrowth

Epithelial ingrowth occurs when the tissue from the outer layer of your cornea (epithelium) starts to grow underneath the LASIK flap. This complication presents in 0 to 3.9 percent of LASIK procedures, although the rate goes up in retreatment (touch-up) cases.

Mild cases of epithelial growth do not need treatment. Severe epithelial growth may cause pain, light sensitivity, and blurred vision. These cases require the surgeon to lift the flap and remove the ingrowth.

Corneal Ectasia

Corneal ectasia is a rare but visually-devastating LASIK complication resulting in significant corneal thinning. Some studies reported an incidence rate between 0.04 to 0.6 percent of LASIK procedures.

You may need a procedure called collagen cross-linking to strengthen your cornea or corneal implants to improve your vision. One of the biggest risk factors for corneal ectasia is keratoconus. This eye disease causes gradual steepening and thinning of the cornea. If your eye surgeon observes early signs of keratoconus, they usually recommend against laser eye surgery. 

Diffuse lamellar Keratitis (DLK)

Diffuse lamellar keratitis (DLK) is a type of inflammation that occurs under the LASIK flap. This complication typically occurs a few days post-surgery. Mild cases of DLK are self-limiting, and most patients are asymptomatic. Severe cases appear as waves of sand in your cornea, which is why they are nicknamed “Sands of the Sahara.”

Severe DLK is treated with frequent doses of steroid eye drops and may require the surgeon to lift the flap and rinse the inflammatory cells out. Bladeless LASIK has a higher risk of DLK versus traditional LASIK.

Infection

Infection requires prompt treatment with antibiotics, and in some cases, the surgeon lifts the flap and applies antibiotic underneath it. Symptoms include pain, redness, and light sensitivity. Overall, infection is rare because the LASIK flap provides protection, and you are prescribed antibiotic eye drops to prevent infection after surgery.

Flap Complications

Flap complications include wrinkles and dislocation of the corneal flap created during LASIK. These problems can happen if patients accidentally rub their eyes after receiving LASIK. A flap dislocation or significant flap wrinkles require the surgeon to reposition the LASIK flap. 

Most dislocations occur within 24 hours of surgery, but some are seen months to years later, usually due to trauma. A review of 41,845 LASIK patients found a flap dislocation rate of only 0.012 percent. 

However, studies comparing only traditional LASIK (not including bladeless LASIK procedures) found a higher flap complication rate of 5 percent. Bladeless LASIK also creates more consistent corneal flaps, which helps with healing. 

Overall, the risk of blindness with LASIK is very low. Over 99 percent of people reach 20/40 visual acuity or better, while 90 percent of LASIK patients achieve 20/20 vision or better. Rarely, serious complications can cause significant vision loss. Following post-surgical care instructions and seeing your eye doctor for scheduled follow-up visits are essential to prevent vision-threatening complications.

Risks & Side Effects of LASIK

Although most people obtain good visual acuity post-LASIK, side effects can affect the overall vision and comfort after surgery. The most frequent symptoms include:

Dry Eyes

Dry eyes after LASIK is one of the most common side effects. Approximately 30 percent of patients experience LASIK-related dry eye. Most dry eye symptoms are mild and resolve within six months of surgery, although a small percentage of people develop chronic dry eye.

However, severe dry eye problems usually occur in people who have dry eyes before LASIK and may be influenced by other factors such as age, hormones, and diet. A traditional LASIK procedure is more likely to cause dry eye versus bladeless LASIK. Artificial tear drops can be used to treat severe cases of dry eye.

Glare, Starbursts, or Halos

Glare, starbursts, or halos are light-related side effects that can affect your night vision. These symptoms are typical during the healing process and subside within a few months or may require an enhancement surgery.

Patients with large pupils are more likely to experience problems. Customized procedures such as wavefront-guided LASIK help minimize these side effects.

Blurry Distance or Near Vision

Blurry distance or near vision may be related to undercorrection, overcorrection, or regression. The vision can be corrected via an enhancement procedure or an eyeglass prescription.

Temporary Loss of Vision

In rare cases, a patient may lose a couple of lines of vision on a Snellen chart. However, this not going to cause legal blindness.

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Monovision LASIK Problems

Monovision LASIK is a procedure to correct near vision for people who need reading glasses. The surgery involves correcting one eye to see distance and the other eye to see up close. Although this option is convenient for patients who do not want to wear glasses, monovision comes with some potential side effects:

  • Blurry vision at far or near — Because you are using one eye at a time, your vision is not as clear as both eyes viewing at the same time.
  • Vision imbalance —  Some people have difficulty getting used to monovision and may feel imbalanced. Symptoms include dizziness or temporary double vision. This feeling usually goes away as your brain adapts to monovision.
  • Reduced depth perception — Although most people who adapt to monovision have no trouble with daily activities, others notice reduced depth perception. If you spend a lot of time driving, playing sports, or doing other activities that require excellent depth perception, monovision may not be the right choice for you.
  • Vision problems/changes — Presbyopia is the process in which your eyes lose the ability to focus up close with age. Because presbyopia continues into your 60s, many people who receive LASIK notice changes in their near vision. In these cases, you may need an enhancement LASIK procedure or use glasses and contact lenses.
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LASIK Recovery Time & What To Expect

Generally, the recovery time across most LASIK procedures (including traditional and bladeless LASIK) is similar. 

Here is a general overview of what to expect during your recovery.

First 24 hours after surgery:

  • Shortly after surgery, the topical anesthesia starts to wear off, and you will experience some discomfort. Many people describe the sensation similar to when you cut onions. 
  • You may experience irritation for a few days after surgery, but you should not have severe pain at any point. If you do, contact your surgeon immediately as this can indicate a severe complication.
  • Generally, you can see reasonably well immediately after LASIK, but your vision may be a little foggy. Sensitivity to light is also common. You will be given dark shades to protect your eyes and someone will need to drive you home.
  • After you get home, it is best to sleep for a few hours. Avoid working on a computer or anything else that can strain your eyes. 
  • Make sure to start using your antibiotic, steroid, and lubricating eye drops per your doctor’s instructions. 
  • You can shower the same day, but avoid washing the eye area and direct the water away from your face.
  • If you feel comfortable, you can drive and go back to work the next day.
  • The eye surgeon will see you for follow up visits the next day, up to six months after your surgery. During these appointments, the doctor can check if your eyes are healing properly, and your vision is stable.

First month after surgery:

  • For the next 1 to 2 weeks, avoid rubbing your eyes and use the eye shields at night to protect your eyes. 
  • You may experience glare and halos that interfere with night vision, but these symptoms usually improve after a few weeks.
  • You might notice some red spots on the whites of your eye. These are broken blood vessels that develop when the suction ring is placed on your eye during surgery. They are harmless and resolve within two weeks. 
  • Avoid hot tubs, steam rooms, pools, oceans, ponds, and lakes for two weeks.
  • Do not use eye makeup for at least a week.
  • Avoid heavy exercise for a week. Do not engage in high-impact sports such as basketball for at least a month. Consider goggles for activities where you may get poked in the eye.
  • Even after you finish the medicated eye drops, it is wise to continue using lubricating drops to help with dry eyes.

Three to six months after surgery:

The total healing time usually takes about six months. However, if you have a high prescription, your eyes may take a bit longer to heal. Your vision typically stabilizes during this time. If your vision is still blurry, the surgeon can evaluate you for an enhancement procedure or prescribe eyeglasses.

Author: Melody Huang, O.D. | UPDATED April 28, 2020
Resources

Chuck, Roy S., et al. “Refractive Errors & Refractive Surgery Preferred Practice Pattern.” Ophthalmology, 2017, doi:10.1016/j.ophtha.2017.10.003.

Cosar, Cemile Banu, et al. “Comparison of Visual Acuity, Refractive Results and Complications of Femtosecond Laser with Mechanical Microkeratome in LASIK.” International Journal of Ophthalmology, vol. 6, no. 3, 18 June 2013, pp. 350–355., doi:10.3980/j.issn.2222-3959.2013.03.18.

Eydelman, Malvina, et al. “Symptoms and Satisfaction of Patients in the Patient-Reported Outcomes With Laser In Situ Keratomileusis (PROWL) Studies.” JAMA Ophthalmology, vol. 135, no. 1, 1 Jan. 2017, pp. 13–22., doi:10.1001/jamaophthalmol.2016.4587.

Ikeda, Tetsuya, et al. “Twelve-Year Follow-Up of Laser In Situ Keratomileusis for Moderate to High Myopia.” BioMed Research International, vol. 2017, 17 May 2017, pp. 1–7., doi:10.1155/2017/9391436.

Moshirfar, Majid, et al. “LASIK Complications.” EyeWiki, 20 Jan. 2015, eyewiki.aao.org/LASIK_Complications.

Sandoval, Helga P., et al. “Modern Laser in Situ Keratomileusis Outcomes.” Journal of Cataract & Refractive Surgery, vol. 42, no. 8, Aug. 2016, pp. 1224–1234., doi:10.1016/j.jcrs.2016.07.012.

Schallhorn, Steven C, et al. “Pupil Size and Quality of Vision after LASIK.” Ophthalmology, vol. 110, no. 8, Aug. 2003, pp. 1606–1614., doi:10.1016/s0161-6420(03)00494-9.

Toda, Ikuko. “Dry Eye After LASIK.” Investigative Opthalmology & Visual Science, vol. 59, no. 14, Nov. 2018, pp. DES109–DES115., doi:10.1167/iovs.17-23538.

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