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( ایران چشم ) IRAN EYE - توصیه های عمومی درباره جراحی عیوب انکساری با لیزر: لیزیک

When is LASIK not for me?

You are probably NOT a good candidate for refractive surgery if:

  • You are not a risk taker. Certain complications are unavoidable in a percentage of patients, and there are no long-term data available for current procedures.
  • It will jeopardize your career. Some jobs prohibit certain refractive procedures. Be sure to check with your employer/professional society/military service before undergoing any procedure.
  • Cost is an issue. Most medical insurance will not pay for refractive surgery. Although the cost is coming down, it is still significant.
  • You required a change in your contact lens or glasses prescription in the past year. This is called refractive instability. Patients who are:

·         In their early 20s or younger, 

·         Whose hormones are fluctuating due to disease such as diabetes,

·         Who are pregnant or breastfeeding, or 

·         Who are taking medications that may cause fluctuations in vision, 

are more likely to have refractive instability and should discuss the possible additional risks with their doctor.

  • You have a disease or are on medications that may affect wound healing. Certain conditions, such as autoimmune diseases (e.g., lupus, rheumatoid arthritis), immunodeficiency states (e.g., HIV) and diabetes, and some medications (e.g., retinoic acid and steroids) may prevent proper healing after a refractive procedure.
  • You actively participate in contact sports. You participate in boxing, wrestling, martial arts or other activities in which blows to the face and eyes are a normal occurrence.
  • You are not an adult.  Currently, no lasers are approved for LASIK on persons under the age of 18.

Precautions
The safety and effectiveness of refractive procedures has not been determined in patients with some diseases. Discuss with your doctor if you have a history of any of the following:

  • Herpes simplex or Herpes zoster (shingles) involving the eye area.
  • Glaucoma, glaucoma suspect, or ocular hypertension.
  • Eye diseases, such as uveitis/iritis (inflammations of the eye)
  • Eye injuries or previous eye surgeries.
  • Keratoconus

Other Risk Factors
Your doctor should screen you for the following conditions or indicators of risk:

  • Blepharitis. Inflammation of the eyelids with crusting of the eyelashes, that may increase the risk of infection or inflammation of the cornea after LASIK.
     
  • Large pupils. Make sure this evaluation is done in a dark room. Although anyone may have large pupils, younger patients and patients on certain medications may be particularly prone to having large pupils under dim lighting conditions. This can cause symptoms such as glare, halos, starbursts, and ghost images (double vision) after surgery. In some patients these symptoms may be debilitating. For example, a patient may no longer be able to drive a car at night or in certain weather conditions, such as fog.
  • Thin Corneas. The cornea is the thin clear covering of the eye that is over the iris, the colored part of the eye. Most refractive procedures change the eye’s focusing power by reshaping the cornea (for example, by removing tissue).  Performing a refractive procedure on a cornea that is too thin may result in blinding complications.
  • Previous refractive surgery (e.g., RK, PRK, LASIK).  Additional refractive surgery may not be recommended.  The decision to have additional refractive surgery must be made in consultation with your doctor after careful consideration of your unique situation.
  • Dry Eyes. LASIK surgery tends to aggravate this condition.

What are the risks and how can I find the right doctor for me?

Most patients are very pleased with the results of their refractive surgery. However, like any other medical procedure, there are risks involved. That's why it is important for you to understand the limitations and possible complications of refractive surgery.

Before undergoing a refractive procedure, you should carefully weigh the risks and benefits based on your own personal value system, and try to avoid being influenced by friends that have had the procedure or doctors encouraging you to do so.

  • Some patients lose vision. Some patients lose lines of vision on the vision chart that cannot be corrected with glasses, contact lenses, or surgery as a result of treatment.
  • Some patients develop debilitating visual symptoms. Some patients develop glare, halos, and/or double vision that can seriously affect nighttime vision. Even with good vision on the vision chart, some patients do not see as well in situations of low contrast, such as at night or in fog, after treatment as compared to before treatment.
  • You may be under treated or over treated. Only a certain percent of patients achieve 20/20 vision without glasses or contacts. You may require additional treatment, but additional treatment may not be possible. You may still need glasses or contact lenses after surgery. This may be true even if you only required a very weak prescription before surgery. If you used reading glasses before surgery, you may still need reading glasses after surgery.
  • Some patients may develop severe dry eye syndrome. As a result of surgery, your eye may not be able to produce enough tears to keep the eye moist and comfortable. Dry eye not only causes discomfort, but can reduce visual quality due to intermittent blurring and other visual symptoms. This condition may be permanent. Intensive drop therapy and use of plugs or other procedures may be required.
  • Results are generally not as good in patients with very large refractive errors of any type. You should discuss your expectations with your doctor and realize that you may still require glasses or contacts after the surgery.
  • For some farsighted patients, results may diminish with age. If you are farsighted, the level of improved vision you experience after surgery may decrease with age. This can occur if your manifest refraction (a vision exam with lenses before dilating drops) is very different from your cycloplegic refraction (a vision exam with lenses after dilating drops).
  • Long-term data are not available. LASIK is a relatively new technology. The first laser was approved for LASIK eye surgery in 1998. Therefore, the long-term safety and effectiveness of LASIK surgery is not known.

Additional Risks if you are Considering the Following:

  • Monovision

Monovision is one clinical technique used to deal with the correction of presbyopia, the gradual loss of the ability of the eye to change focus for close-up tasks that progresses with age. The intent of monovision is for the presbyopic patient to use one eye for distance viewing and one eye for near viewing. This practice was first applied to fit contact lens wearers and more recently to LASIK and other refractive surgeries. With contact lenses, a presbyopic patient has one eye fit with a contact lens to correct distance vision, and the other eye fit with a contact lens to correct near vision. In the same way, with LASIK, a presbyopic patient has one eye operated on to correct the distance vision, and the other operated on to correct the near vision. In other words, the goal of the surgery is for one eye to have vision worse than 20/20, the commonly referred to goal for LASIK surgical correction of distance vision. Since one eye is corrected for distance viewing and the other eye is corrected for near viewing, the two eyes no longer work together. This results in poorer quality vision and a decrease in depth perception. These effects of monovision are most noticeable in low lighting conditions and when performing tasks requiring very sharp vision. Therefore, you may need to wear glasses or contact lenses to fully correct both eyes for distance or near when performing visually demanding tasks, such as driving at night, operating dangerous equipment, or performing occupational tasks requiring very sharp close vision (e.g., reading small print for long periods of time).

Many patients cannot get used to having one eye blurred at all times. Therefore, if you are considering monovision with LASIK, make sure you go through a trial period with contact lenses to see if you can tolerate monovision, before having the surgery performed on your eyes. Find out if you pass your state's driver's license requirements with monovision.

In addition, you should consider how much your presbyopia is expected to increase in the future. Ask your doctor when you should expect the results of your monovision surgery to no longer be enough for you to see near-by objects clearly without the aid of glasses or contacts, or when a second surgery might be required to further correct your near vision.

  • Bilateral Simultaneous Treatment

You may choose to have LASIK surgery on both eyes at the same time or to have surgery on one eye at a time. Although the convenience of having surgery on both eyes on the same day is attractive, this practice is riskier than having two separate surgeries.

If you decide to have one eye done at a time, you and your doctor will decide how long to wait before having surgery on the other eye. If both eyes are treated at the same time or before one eye has a chance to fully heal, you and your doctor do not have the advantage of being able to see how the first eye responds to surgery before the second eye is treated.

Another disadvantage to having surgery on both eyes at the same time is that the vision in both eyes may be blurred after surgery until the initial healing process is over, rather than being able to rely on clear vision in at least one eye at all times.

Finding the Right Doctor
If you are considering refractive surgery, make sure you:

  • Compare. The levels of risk and benefit vary slightly not only from procedure to procedure, but from device to device depending on the manufacturer, and from surgeon to surgeon depending on their level of experience with a particular procedure.
  • Don't base your decision simply on cost and don't settle for the first eye center, doctor, or procedure you investigate. Remember that the decisions you make about your eyes and refractive surgery will affect you for the rest of your life.
  • Be wary of eye centers that advertise, "20/20 vision or your money back" or "package deals." There are never any guarantees in medicine.
  • Read. It is important for you to read the patient handbook provided to your doctor by the manufacturer of the device used to perform the refractive procedure. Your doctor should provide you with this handbook and be willing to discuss his/her outcomes (successes as well as complications) compared to the results of studies outlined in the handbook.

Even the best screened patients under the care of most skilled surgeons can experience serious complications.

  • During surgery. Malfunction of a device or other error, such as cutting a flap of cornea through and through instead of making a hinge during LASIK surgery, may lead to discontinuation of the procedure or irreversible damage to the eye.
  • After surgery. Some complications, such as migration of the flap, inflammation or infection, may require another procedure and/or intensive treatment with drops. Even with aggressive therapy, such complications may lead to temporary loss of vision or even irreversible blindness.

Under the care of an experienced doctor, carefully screened candidates with reasonable expectations and a clear understanding of the risks and alternatives are likely to be happy with the results of their refractive procedure.

Advertising
Be cautious about "slick" advertising and/or deals that sound "too good to be true." Remember, they usually are. There is a lot of competition resulting in a great deal of advertising and bidding for your business. Do your homework.

If you want to know more about advertising ethics, do's and don'ts, or want to report on false advertising, explore the following websites

What should I expect before, during, and after surgery?

What to expect before, during, and after surgery will vary from doctor to doctor and patient to patient.  This section is a compilation of patient information developed by manufacturers and healthcare professionals, but cannot replace the dialogue you should have with your doctor.  Read this information carefully and with the checklist, discuss your expectations with your doctor.

Before Surgery
If you decide to go ahead with LASIK surgery, you will need an initial or baseline evaluation by your eye doctor to determine if you are a good candidate. This is what you need to know to prepare for the exam and what you should expect:

If you wear contact lenses, it is a good idea to stop wearing them before your baseline evaluation and switch to wearing your glasses full-time. Contact lenses change the shape of your cornea for up to several weeks after you have stopped using them depending on the type of contact lenses you wear. Not leaving your contact lenses out long enough for your cornea to assume its natural shape before surgery can have negative consequences. These consequences include inaccurate measurements and a poor surgical plan, resulting in poor vision after surgery. These measurements, which determine how much corneal tissue to remove, may need to be repeated at least a week after your initial evaluation and before surgery to make sure they have not changed, especially if you wear RGP or hard lenses.  If you wear:

  • soft contact lenses, you should stop wearing them for 2 weeks before your initial evaluation.
  • toric soft lenses or rigid gas permeable (RGP) lenses, you should stop wearing them for at least 3 weeks before your initial evaluation.
  • hard lenses, you should stop wearing them for at least 4 weeks before your initial evaluation.

LASIK Surgery Checklist

Know what makes you a poor candidate

Career impact - does your job prohibit refractive surgery?
Cost - can you really afford this procedure?
Medical conditions - e.g., do you have an autoimmune disease or other major illness? Do you have a chronic illness that might slow or alter healing?
Eye conditions - do you have or have you ever had any problems with your eyes other than needing glasses or contacts?
Medications - do you take steroids or other drugs that might prevent healing?
Stable refraction - has your prescription changed in the last year?
High or Low refractive error - do you use glasses/contacts only some of the time? Do you need an unusually strong prescription?
Pupil size - are your pupils extra large in dim conditions?
Corneal thickness - do you have thin corneas?
Tear production - do you have dry eyes?

Know all the risks and procedure limitations

Overtreatment or undertreatment - are you willing and able to have more than one surgery to get the desired result?
May still need reading glasses - do you have presbyopia?
Results may not be lasting - do you think this is the last correction you will ever need? Do you realize that long-term results are not known?
May permanently lose vision - do you know some patients may lose some vision or experience blindness?
Dry eyes – do you know that if you have dry eyes they could become worse, or if you don’t have dry eyes before you could develop chronic dry eyes as a result of surgery?
Development of visual symptoms - do you know about glare, halos, starbursts, etc. and that night driving might be difficult?
Contrast sensitivity - do you know your vision could be significantly reduced in dim light conditions?
Bilateral treatment - do you know the additional risks of having both eyes treated at the same time?
Patient information - have you read the patient information booklet about the laser being used for your procedure?

Know how to find the right doctor

Experienced - how many eyes has your doctor performed LASIK surgery on with the same laser?
Equipment - does your doctor use an FDA-approved laser for the procedure you need? Does your doctor use each microkeratome blade only once?
Informative - is your doctor willing to spend the time to answer all your questions?
Long-term Care - does your doctor encourage follow-up and management of you as a patient?  Your preop and postop care may be provided by a doctor other than the surgeon.
Be Comfortable - do you feel you know your doctor and are comfortable with an equal exchange of information?

Know preoperative, operative, and postoperative expectations

No contact lenses prior to evaluation and surgery - can you go for an extended period of time without wearing contact lenses?
Have a thorough exam - have you arranged not to drive or work after the exam?
Read and understand the informed consent - has your doctor given you an informed consent form to take home and answered all your questions?
No makeup before surgery - can you go 24-36 hours without makeup prior to surgery?
Arrange for transportation - can someone drive you home after surgery?
Plan to take a few days to recover - can you take time off to take it easy for a couple of days if necessary?
Expect not to see clearly for a few days - do you know you will not see clearly immediately?
Know sights, smells, sounds of surgery - has your doctor made you feel comfortable with the actual steps of the procedure?
Be prepared to take drops/medications- are you willing and able to put drops in your eyes at regular intervals?
Be prepared to wear an eye shield - do you know you need to protect the eye for a period of time after surgery to avoid injury?
Expect some pain/discomfort - do you know how much pain to expect?
Know when to seek help - do you understand what problems could occur and when to seek medical intervention?
Know when to expect your vision to stop changing - are you aware that final results could take months?
Make sure your refraction is stable before any further surgery - if you don't get the desired result, do you know not to have an enhancement until the prescription stops changing?

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