What is Lasik?
LASIK (laser-assisted in situ keratomileusis) surgery is perhaps the most well-known refractive surgery today. LASIK can help patients with myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. During the procedure, the doctor makes a flap in the outer layer of the corner to reach the underlying tissue and then uses a laser to reshape the tissue which allows the cornea to then focus light properly. The procedure is usually painless and vision is usually clear within a few hours.
Recent advances in the field have developed subcategories of LASIK surgery such as Bladeless LASIK, which uses a laser rather than a mechanical tool to make the initial flap, or Wavefront (custom) LASIK which uses computer mapping to guide the reshaping of the cornea and can create a much more precise vision correction for very subtle optical imperfections. There is also a procedure called Epi-LASIK in which following the procedure, the doctor applies a soft contact lens to protect the surgical area, holding the flap in place while it heals.
LASIK or laser-assisted in situ keratomileusis is a refractive surgery that is used to correct myopia (nearsightedness), hyperopia (farsightedness), and astigmatism as an alternative to eyeglasses or contact lenses. LASIK is currently the most common of the refractive eye surgeries, largely because of the relatively low risk and the quick recovery and improvement in eyesight.
Also known as laser eye surgery or laser vision correction, LASIK uses a laser to reshape the cornea which is responsible for clear vision. The procedure is quick and relatively painless and eyesight is usually improved to 20/20 vision within one day of the surgery.
Common lasik questions
LASIK is an outpatient procedure, which takes about 15 minutes for the actual surgery on both eyes and an hour total with recovery. A topical anesthetic drop is used and there is no need for bandaging or stitches following the procedure. The doctor will start by stabilizing the eye and then making a small flap in the outer layer of the cornea. Then with access to the underlying tissue, he uses a laser to reshape the corneal tissue and re-closes the flap, which will heal on its own. The nature of the corneal reshaping depends on the type of refractive error.
Wavefront LASIK uses computer mapping technology to guide the laser treatment based on the precise shape of the cornea. This can correct very precise issues, provide much sharper vision than non-wavefront LASIK, and can reduce complications such as halos, glare, and problems seeing at night.
During the procedure, you may feel some pressure on your eye while the laser is working. Immediately following you will likely experience some blurriness and may feel burning or itching (be sure not to rub your eyes!). For your journey home you will be given protective shields to guard your eyes and will need someone to drive you. You will also be prescribed medicated eye drops for a week or so to aid in healing and prevent infection. Your doctor may also recommend artificial tears to moisten the eyes and keep them comfortable in the days following the procedure.
The day after the surgery you will be asked to visit your eye doctor (or the surgeon) for a checkup and to evaluate whether you can drive. Most people experience an improvement in vision by then, although for some it can take a few days or even a week. Your eyes may be sensitive to light for a day or two as well. You will likely be advised to rest for a day or two and to refrain from strenuous physical activity for about a week until further healing has taken place.
Most people achieve at least 20/20 vision following the surgery, although this can vary and there are cases where 20/40 vision is obtained or where people continue to wear glasses or contacts with a much lesser prescription. Some patients have light sensitivity, particularly when driving at night, and also suffer from seeing halos around lights or glare. There are glasses and lenses available to reduce this glare and assist with night driving.
For some, it can take weeks or even months until the vision completely stabilizes. Occasionally, after a few months, patients who do not experience perfect results will schedule an enhancement or touch-up surgery to correct the vision even further.
The ideal LASIK candidate is a patient over 18 with generally healthy eyes. Since the procedure involves shaping the cornea by removing some of the tissue, it is not ideal for individuals with a thin cornea or any sort of corneal condition or disease. Patients with chronic dry eyes might also be disqualified as LASIK can often exacerbate these symptoms.
During a comprehensive eye exam, your eye doctor will assess your eligibility by looking at the general health of your eye including your cornea, your pupil, the moisture in your eye, the type of refractive error you have, and whether you have any other eye conditions of concern.
For the right candidate, LASIK can offer a lifestyle improvement in giving clear vision without the need for glasses or contact lenses, however, the results are not guaranteed. You and your eye doctor need to weigh the benefits and the potential risks based on your personal needs.
LASIK Risks and Complications
LASIK is the most common refractive eye surgery, partially because the risks and complications are low. The majority of patients don’t experience any long-term complications as a result of the surgery. Nevertheless, as with any surgical procedure, there are some risks, however rare they are and it is important to know them and to discuss them with your eye doctor or surgeon before undergoing the surgery.
Side effects of LASIK
Several side effects are somewhat common immediately post-op and in some instances can last longer – sometimes indefinitely. Those include:
About half of LASIK patients experience dry eyes, which are usually a temporary side effect that resolves within 3-6 months after the surgery. Your doctor will likely prescribe artificial tears in the days and weeks following the surgery which should be continued as long as the symptoms persist. Because of this, it is usually recommended that patients with a history of chronic dry eyes opt for another type of refractive surgery such as PRK, another style of laser refractive surgery with reduced risk.
Eye Infection or Irritation
While not common due to the eye drops and checkups prescribed post-surgery, there is a chance of developing an eye infection. If this does occur, it can be treated with antibiotic eye drops, anti-inflammatories or sometimes may require other treatment such as oral antibiotics. If you are experiencing symptoms of an eye infection such as redness, pain, discomfort, discharge, or any vision change, see your eye doctor immediately. As a precaution, it is imperative to follow your surgeon’s instructions for your post-operative care including prescription medications and doctor’s visits.
Following surgery, you may experience certain vision issues such as poor night vision, double vision, halos around lights or glare. These side effects are common and can last up to a few weeks, but typically go away. Some patients report a lasting reduction in vision in low-light conditions and may require vision aids for seeing better at night.
Other risks of LASIK include surgical errors, many of which can be corrected by a follow-up surgery. These include:
Overcorrection or Undercorrection
The key to vision improvement in LASIK is the accurate reshaping of the corneal tissue. If too much is removed or not enough is removed, your vision will remain imperfect and when possible may require a follow-up procedure to obtain the clear vision being sought.
Perhaps the greatest risk involved in LASIK is the accurate creation and healing of the flap of the cornea that is lifted to reshape the underlying tissue and replaced after. If the flap in the cornea is not made accurately, cut too thick or too thin, and not carefully replaced on the eye, it can cause complications in the shape of the eye surface and therefore clear vision. Studies indicate that these complications occur usually in under 6% of cases and the experience and skill of the surgeon play a large role.
There can also be complications in the healing process of the flap which include infection or excessive eye tearing.
There is a chance, albeit small that the surgery can result in a loss of vision or reduction in visual clarity due to complications with the surgery.
It is quite rare for any permanent damage or vision loss to occur as a result of LASIK and usually any vision problems can be corrected by a follow-up procedure. However, as with any surgical procedure, there are risks, so it is important to reduce your risks by finding an experienced surgeon and carefully considering your suitability for the surgery in the first place.
LASIK - Criteria for Success
LASIK can be a great solution for individuals that want clear vision without glasses or contact lenses, but it is not an ideal or even safe choice for everyone. If you have certain risk factors, not only will you likely not experience the positive results of LASIK but you could even experience unwanted complications.
If you are considering LASIK, keep in mind the following risk factors that typically disqualify a patient from candidacy:
- Under 18 years old: Children’s eyes are constantly changing and it is only once a child reaches the age of 18, that we can be sure that their vision has stabilized. Patients should experience at least a year of stable vision before scheduling LASIK otherwise they are risking the chance of having to repeat the surgery.
- Pregnant or Nursing Women: Hormonal changes during pregnancy can cause changes to your eyes and vision and could take up to a year or so to return to normal. Additionally, some of the medications used during or after LASIK could be harmful to a baby that is in utero or nursing. If you are pregnant, trying to get pregnant, or nursing, speak to your eye doctor about if and when you can consider LASIK.
- Very High Prescription: Patients with particularly high myopia or hyperopia may require too much tissue removal to properly fix the vision, increasing the risk of the procedure. In such cases, your doctor may recommend an alternate procedure such as PRK.
- Eye Problems or Diseases: If your eyes are not healthy, you can increase your risks of complications and inhibit the process of healing that takes place following the surgery. For chronic issues such as dry eyes, cataracts, glaucoma, or other serious problems you may be disqualified from LASIK or any other surgical procedure. Other conditions such as an eye infection or injury may simply require you to wait until your eye is completely healed.
- Irregular Eye Anatomy (Such as Large Pupil Size or Thin Corneas): Patients with exceptionally large pupils may be disqualified from LASIK due to a higher incidence of negative side effects such as poor night vision, halos, double vision, or glare. For LASIK to be successful, the cornea needs to be a certain minimal thickness. For those with thin corneas, an alternate treatment may be recommended.
- Systemic and Autoimmune Medical Conditions: Certain systemic diseases and medical conditions such as diabetes, HIV, immunodeficiency, or rheumatoid arthritis that can affect your body’s ability to heal properly can disqualify a patient from LASIK. Certain medications can also disqualify you from being a candidate.
- Prior Eye Injury: Certain eye injuries, especially those that result in corneal scarring can pose a risk for successful LASIK surgery.
Eye doctors and surgeons may have differing opinions as to which conditions and circumstances will disqualify you from LASIK candidacy. Your eye doctor and/or surgeon will complete a thorough exam to assess the risks and potential outcomes to determine if LASIK is right for you.