LASIK is the acronym for laser in situ keratomileusis, sometimes referred to as laser assisted in situ keratomileusis. The name refers the use of a laser to reshape the cornea without invading the adjacent cell layers. In situ is Greek for “in the natural or normal place.” Medically, in situ means confined to the site of origin without invasion of neighbouring tissues. Kerato is the Greek word for cornea and mileusis means “to shape.”

LASIK can benefit a great number of people with myopia, hyperopia and astigmatism. Candidates should have a strong desire to be less dependent on corrective lenses, have established realistic expectations, and understand the risks associated with the surgery.

There are a number of factors that doctors must evaluate before they can determine who is an eligible candidate for LASIK. Some doctors deem certain pre-existing conditions contraindications to the procedure and will not perform surgery if you possess them. Sometimes, factors exist that preclude a patient from being an ideal candidate for LASIK surgery. In many cases, a surgeon may still be able to safely perform the procedure, given that the patient and physician have adequately discussed the risks and benefits and set realistic expectations for results.

LASIK is only one type of refractive surgery available to patients. Although you may not be eligible for LASIK, you may be eligible for a different procedure like a lens implant or Phakic IOL implant. You would need to discuss your options with your ophthalmologist.

Most surgeons agree that if you are comfortable wearing contact lenses and are not bothered by being dependent on them, you should carefully evaluate the risks and benefits of LASIK.

LASIK improves the uncorrected vision – one’s vision without wearing corrective lenses – in most patients who have the procedure. Over 90% of patients with low to moderate myopia will achieve 20/40 vision, which is considered the minimum allowed by most states and provinces to drive without having to wear contacts or glasses. Over half of all patients can expect to achieve 20/20 vision or better. However, there are no guarantees that you will have perfect vision, and patients with high myopia (more than -7D) and high hyperopia (more than +4D) should have a different set of expectations. People who are most satisfied with the results of laser correction possess realistic expectations of what their vision will be like after surgery.

Fast visual recovery characterizes this operation. Most patients achieve good vision the day of surgery and find that their eyes feel fairly normal within a day. However, vision can continue to improve, and best vision can still take two to three months to occur. If necessary, adjustments to the surgery called enhancements can be done. Patients who undergo hyperopic LASIK often need to wait longer to able to see clearly. Typically, they are unable to see with intense clarity for one or two weeks, with best vision coming in several months post-operatively.

Most patients who have LASIK do not need to wear glasses for their daily activities. However, patients may need to wear reading glasses if they are over the age of 40. This is caused by the normal aging of the eye known as presbyopia. This condition occurs with or without LASIK. Some patients may need a minimal prescription for some activities. Those patients who currently have bifocals will still need reading glasses after the surgery unless they opt for a treatment plan called monovision, wherein one eye is corrected for distance and the other for near vision.

Most patients do not notice a change; however some patients will notice glare, halos or starburst around objects in dim or low-light conditions. For the vast majority, these symptoms are temporary. However, others will continue to experience them for several months or longer. Although these symptoms do not necessarily interfere with visual acuity as it is measured by an eye chart, for some patients, the experience can interfere with their activities.

Some patients who seek LASIK have underlying dry eye syndrome that has not been diagnosed. There appears to be a correlation between pre-operative dry eye syndrome and developing more pronounced dry eye symptoms post-operatively. Therefore, many doctors test for dry eye prior to making a decision regarding eligibility.

LASIK is a surgical procedure that permanently removes corneal tissue to reshape the eye in order to improve refraction. The physical results are permanent. However, you should be aware that since the eyes can still change with time, and LASIK does not affect a number of visual conditions associated with age. For example, LASIK does not prevent presbyopia or affect this condition once it does occur.

Depending on the cause, retreatment may be a viable solution to vision changes later in life, and other treatment options exist. You would need to see your ophthalmologist to determine the cause of the change and to determine which option is best for you.

Patients are given a topical anesthetic (eye drops) to numb the eye, so they experience no pain during the procedure. When the surgeon applies the vacuum ring, the patient experiences a sensation of pressure just before his or her vision fades for a few seconds. The microkeratome – the instrument the surgeon uses to create the flap – and the laser do not cause any pain or discomfort. For several hours after the procedure, many patients describe a mild burning sensation, such as after opening the eyes while swimming in chlorinated water. Therefore, taking a nap for the first 2 to 3 hours after LASIK is encouraged. After the first few hours, this uncomfortable feeling usually subsides.

The procedure is done with topical anesthetic (eye drops) to numb the eye. Patients may be given a small amount of oral sedative to help them relax.

According to several large studies, there is approximately less than 2% intra-operative and less than 3-5% post-operative complication rate. Most of these complications do not result in loss of 2 or more lines of best corrected visual acuity or interfere with vision long term. The rate of severe complications should be substantially less than 1%. It is important for patients to understand that LASIK is surgery, and a small incidence of complications is to be expected.

You can have bilateral simultaneous LASIK (both eyes done at the same time). In fact, the practice is common. However, in some circumstances, surgeons or patients will determine that it is best to wait between eyes in order to evaluate the results. Hyperopic LASIK patients do not experience the extremely fast visual recovery that myopic patients do. Therefore, some surgeons prefer to operate on their eyes separately. Patients should discuss their options with their ophthalmologist.

There are a number of different options to help patients deal with their vision between procedures. Some patients who do not have bilateral surgery will begin wearing a contact lens in the eye that has not undergone surgery. This practice gives them an opportunity to use their two eyes simultaneously. However, the contact lens will need to be removed at least three days prior to the second surgery. Others function by using the operated eye immediately without use of a contact lens in the opposite eye. This solution may work for nearsighted patients with a moderate refractive error (less than six diopters). A patient with a refractive error above six diopters who does not wear a contact lens may be unable to use both eyes together due to the large difference in refractive error between the eyes. Removing one lens from a pair of glasses is usually not useful. Doing so could cause double vision and eye strain.

It depends on your occupation. Certain jobs that require intense clarity of vision (dentistry and surgery, for example) may be difficult to perform for one or two days. Most patients can return to work the next day, assuming their vision is adequate for their job. However, some people may feel fatigued for a day or so following surgery.

You can resume most normal activities immediately after surgery. However, for at least two weeks you will need to avoid activities that would cause perspiration to run into the eyes. You should wear safety glasses while playing contact sports whether or not you have had surgery. But if you do not routinely wear safety glasses, your surgeon may recommend wearing them for at least one month after LASIK. You will also need to avoid such activities as contact sports and swimming for several weeks. It is important to talk specifically with your doctor about limitations on activities after LASIK.

Patients may experience some discomfort and/or blurred vision for a few hours after surgery. And most patients receive a sedative prior to surgery. Therefore, you cannot drive home after undergoing the procedure, and you should plan not to drive for at least twenty-four hours.