Overview of risks and side effects of LASIK eye surgery

Overview of risks and side effects of LASIK eye surgery
March 5, 2014 11:48 AM

A perfect and clear vision is a blessing of nature. Life without clear vision would be dull and colorless. The refractive errors of eye like myopia (near sightedness), hypermetropia (long sightedness) and astigmatism make it difficult for one to enjoy clean and colorful vision. In such situations, one is compelled to wear glasses or contact lenses to improve vision. Glasses are not only considered a stigma for the beauty of face but they also limit one’s ability to participate in various activities of life like sports or activities that require sharp and accurate vision.

What is LASIK?

People often come to ophthalmologist to seek a permanent cure for their eye sight problem because they do not want to wear glasses anymore due to cosmetic reasons. In such scenario, the doctors usually recommend LASIK eye surgery for correcting the refractive errors of eye. In lay man language LASIK is known as laser treatment for eye sight problems but in scientific terminology it stands for “Laser Assisted in Situ Keratomileusis”.

In this therapy, a laser beam is used to reshape the cornea in order to improve the vision. Laser beams remove the excess corneal tissue, which allows the light to bend and focus more precisely on the retina to produce a sharp and clear image. In most of the cases, LASIK serves as a permanent alternative to glasses and contact lenses. The success rate of LASIK operation is high, as high as 95%.

However, like other surgical procedures, the risks and complications associated with LASIK surgery cannot be neglected.

Complications, side effects and risks of LASIK

Let’s have a look at some of the side effects and risks of LASIK eye surgery:

Under correction and overcorrection

In LASIK surgery, a hinge shaped flap is created in the superficial lining of cornea. After lifting this flap carefully, the underlying corneal tissue is removed with the help of laser light or microkeratome. The amount of tissue that is removed depends on the type of refractive error of eye. But sometimes if the operation is not done carefully, the problems of under correction and overcorrection can occur. In under correction the amount of corneal tissue removed is too little, while in overcorrection more than needed corneal tissue is removed leading to corneal thinning.

The result is blurring of vision. The patient will not be able to see things clearly even after the completion of laser surgery. In cases of faulty operation, an additional laser therapy is done to correct the errors. Under correction can be corrected easily with additional refractive surgery but over corrections are very difficult to be treated because too much corneal tissue has already been removed. Another surgical procedure in this situation can be very risky as it can make the cornea too much fragile, leading to several other complications.

Halos, glares and double vision

Like any other body part, the cornea also needs time to heal properly after a surgery. During this healing phase of cornea, the patients often complain of visual disturbances and mild irritation of the eyes. The patient may experience blurred vision, double vision and increased sensitivity to light. Sometimes the glare, halos, starburst and streaks are reported by the patients when exposed to bright lights. These glares are actually the response of eye to bright light, causing physical discomfort and blurring of vision. However, the symptoms of visual disturbance resolve within 3 to 6 months. In this duration, the patients may have reduced night vision and might not be able to drive properly.

Dry eyes

Our eyes have been provided with a natural lubricating mechanism in the form of tears. The tear film spreading over cornea nourishes it, lubricates it and protects it from friction produced by the rubbing of eyelids. When tears are not produced, the corneal surface gets dry. Blinking in the absence of tear film will rub the cornea against eyelids, leading to discomfort, redness and pain.

Dry eyes are one of the most common side effects of LASIK surgery. The patients feel burning pain and often complain of the presence of a foreign body in the eyes, which can be quite painful sometimes. The symptoms of dry eyes diminish within few weeks to months. Your doctor may ask you to use lubricating eye drops several times a day to soothe the discomfort in eyes.

Visual regression

No doubt, after the surgery the vision is improved but sometimes this improvement in vision is just temporary. Over the time, the vision may return to point where it was before the surgery. An additional or enhancement procedure may be required to prevent the visual regression.


Removal of too much corneal tissue can cause thinning of cornea. This thin cornea has tendency to bulge forward making the surface of cornea irregular. The light rays after passing through this uneven surface are not focused at one point, resulting in a condition called astigmatism. The patient may experience the symptoms of blurred or double vision. Additional surgery has to be done to fix this side effect of LASIK.

Eye infection

Like any other surgical procedure, the chances of infection are also there in LASIK eye surgery. The doctor usually recommends topical antibiotics and steroids to reduce the risks of infection and inflammation of eyes. However, if the infections are left untreated this may lead to vision loss and visual distortions.

Flap complications

In LASIK operation, a hinge shaped flap is created on the corneal surface, then the underneath corneal tissue is removed and finally the flap is re-positioned. When the flap is not adhered back properly, wrinkles are formed resulting in visual disturbances.

Some of the common flap complications include:

  • Epithelial overgrowth: After surgery, the corneal epithelial cell beneath the flap heal own their own naturally. But in some cases, these epithelial cells continue to grow abnormally that possess a hindrance to vision.
  • Diffused lamellar keratitis (DLK): Mild inflammation of cornea after surgery is common. But sometimes an uncontrolled inflammatory response is initiated that can cause scarring of cornea and vision loss.
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Written by: Michal Vilímovský (EN)
Education: Medical student, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic
Published: March 5, 2014 11:48 AM
Next scheduled update: March 5, 2016 11:48 AM
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