Is LASIK safe?

Excimer laser corneal refractive surgery, commonly called “corrective eye surgery,” helps near-sighted patients improve their vision. Laser eye surgery has the added benefit of allowing you to escape the inconvenience of glasses and contact lenses. In recent years, a growing number of near-sighted people have chosen to undergo laser eye surgery. As with any surgery, however, laser eye surgery will involve artificially-induced physical changes. The surgery changes the structure of the front part of the eye called the cornea. Also, the surgery could introduce complications and potential hazards to the health of your eyes. Safety issues surrounding laser eye surgery have been controversial. Here, I want to discuss this topic to quell the widespread fears while still painting a realistic picture of what the surgery involves.

China was first introduced to laser eye surgery in the 1990s, giving the procedure about 18 years of history in the country. Since its introduction, laser eye surgery methods and equipment have undergone rapid evolution, and all related technology has been constantly improved. The procedure has gone by the names of RK, PRK, LASIK, LASEK, and Epi-LASIK, but they all describe the same general procedure. The most mainstream form of laser eye surgery is LASIK (laser in situ keratomileusis). The surgery generally proceeds this way: Under the control of a computer, the outer layer of the cornea is cut away as a flap by a laser. Adjustments are made to the front of the cornea, and then the corneal flap is replaced.

Should I get laser eye surgery?

A lot of patients who visit the BJU Eye Clinic ask me this question. I usually respond with a description of ideal and non-ideal candidates for the procedure.

First, let’s talk about people who are severely near-sighted (who have severe myopia) or people whose prescription for one eye differs by more than 250 degrees from the other eye. These people are highly suited for laser eye surgery. Severe myopia seriously affects a patient’s quality of life and is the cause of much inconvenience, especially for people who have to wear different glasses for different activities. When a person has different prescriptions for each eye, and the difference is 250 degrees or more, this condition is medically known as “anisometropia.” These people have a hard time wearing glasses or finding ones that suit their needs. If you fall into one of these categories, AND you do not like to wear contact lenses or have trouble with contacts, you should strongly consider laser eye surgery to correct your vision.

The ideal candidate would be older than 18, has had relatively healthy eyes for the past two years, and has maintained a stable prescription. Additionally, the candidate would have a corneal thickness greater than 500 nm.

Let’s talk about people who should NOT undergo laser eye surgery. These include people who…

• experience inflammation around the eyes (conjunctivitis, keratitis)
• have severely dry eyes
• have a history of glaucoma
• have a family history of retinal detachment
• suffer from collagen-related disease or diseases that affect corneal healing
• are actively and frequently engaged in outdoor sports
• enjoy extreme sports
• often do a lot of heavy manual labor and are at high risk for head trauma
• have large pupils
• often are required to drive at night
• will never achieve 20/20 vision (perfect visual acuity) for biological reasons

Notes for after the surgery

Post-surgery complications make up a large part of the controversy surrounding laser eye surgery. These complications include dry eyes, experiencing glares, and compromised night vision.

There are things you can do to address some of these issues. After surgery, your cornea will take some time to heal, and this affects the secretion of tears, thus causing your eyes to become dry. You can use artificial tears (eye drops) or eat foods rich in Omega-3’s. In general, if you’re practicing good eye care, your dry eyes will revert to normal after six months. However, due to individual differences in each individual’s corneal healing, try to avoid extreme sports or heavy physical labor. If you experience eye trauma before your eyes have completely healed, you corneal flap might detach again.

Because the procedure involves reshaping the cornea, the curvature changes and affects night vision. When light enters the eye and passes through the cut zones and the uncut zones of the cornea, the light might be deflected in a way that distorts what you see. This is especially likely at night (or in the dark) because the pupil can become fully dilated and cover an area larger than the cut zones. In these cases, the patient will experience a “glare.” This is why people who need to drive at night should not undergo laser eye surgery.

People who have undergone laser eye surgery need to be careful about the medicines they take during the post-surgery recovery period. They should engage in good eye care habits and avoid eye trauma and strenuous exercise. In general, everyone needs to establish good eye care habits in the long run to prevent near-sightedness from recurring.

Can laser eye surgery help with far-sightedness?

Far-sightedness (presbyopia) is a phenomenon of aging, in which the flexibility of your lens declines. Regardless of how near sighted you are/were, you will experience presbyopic symptoms as you age, especially when reading. Laser eye surgery can correct near-sightedness or far-sightedness, but the far-sightedness will continue to develop as people age. In addition, the earliest people to undergo laser eye surgery in China have now entered middle age and are beginning to develop cataracts. The traditional techniques used to calculate intraocular lens (IOL) prescriptions patients with cataracts are actually not recommended for cataract patients who have had laser eye surgery. For cataract patients who have had laser eye surgery, surgeons would need to calculate their IOL prescriptions based on measurements taken before their laser eye surgery. Therefore, patients who seek laser eye surgery should keep good records of their eye measurements before and after the procedure.

The truth is, no procedure is 100% safe. Whether you get laser eye surgery or simply wear glasses or contact lenses, you are at risk. A successful laser eye surgery requires a highly skilled surgeon who has both the necessary qualifications and experience, advanced equipment and technology, a thorough and accurate pre-operative assessment, and full cooperation from the patient. If you believe you are a good candidate for laser eye surgery, consult a professional eye doctor for a detailed preoperative examination and a surgery plan.

Finally, even if you do not plan to undergo laser eye surgery, you should still take care of your eyes and schedule regular eye examinations.