Lasik and Its Variations

Patient Hannah with Dr Caster

I would 100% recommend the Caster Eye Center to everyone.

– Hannah

Types of Laser Vision Correction

Laser vision correction changes the sharpness of the vision by using a cold laser to microscopically alter the outer curvature of the eye. With our advanced technology, the entire treatment takes less than five minutes and is painless. We perform all three of the major versions of laser vision correction:

1. Lasik. The most common version of laser vision correction is Lasik, which has been performed in the United States since 1996. Dr. Caster was one of the twenty doctors in the United States who performed Lasik treatments as part of the original FDA approval process of Lasik. Lasik is a two-step process. The first step is the creation of a flap, which enables us to apply the second step, the laser reshaping of the eye, below the outer surface. By applying the treatment below the surface, we allow the eye to heal very quickly without any significant discomfort. We perform the Lasik version in the majority of our patients.

2. PRK, also known as Lasek or Advanced Surface Treatment. PRK is preferable for some of our patients, especially those with moderate dry eyes, thin corneas, irregularly shaped corneas, or certain hobbies such as boxing. PRK has also been performed by Dr. Caster since 1996. In PRK, the laser reshaping of the vision is performed near the surface of the eye, rather than deeper within the eye as in Lasik or Smile Lasik.

3. Smile (Small Incision Lenticule Extraction). Smile Lasik is the latest version of laser vision correction. Smile uses a cold laser to separate a thin lens-like layer from within the cornea, which is then separated and removed by the doctor through a tiny channel. Smile creates an opening that is only a fraction of the size of a Lasik flap, so Smile may be thought of as “small-incision Lasik”.

Lasik, PRK, and Smile all produce the exact same improvement in vision. Each procedure offers advantages and disadvantages, so the best technique for you is based upon your individual eye measurements, visual needs, and lifestyle situation. You will discuss this thoroughly with Dr. Caster when you meet with him during your initial consultation.

Laser vision correction has undergone tremendous improvements since first introduced in 1996. So what you read or hear from people who had the procedure many years ago may not be accurate for today’s laser vision correction technology. Of course, the vast majority of people who had the procedure in 1996 up until today are very, very happy, but we have figured out how to prevent most of the problems that some patients experienced with the earliest technology of Lasik. The treatments are very fast now, taking usually less than five minutes. PRK (but not Lasik) used to be associated with pain, but that has largely been resolved. Dryness, if it occurs, is now typically only temporary and largely diminished by taking Omega-3 pills. And with the newer Allegretto technology, the degree of night halos and glare after treatment is actually on average less than the pre-treatment amount of halos and glare that the patient had with contact lenses and glasses. Less halos and glare on average than contacts or glasses!

Wavefront Technology

Wavefront laser vision correction is an improved way of performing laser treatment that produces, on average, sharper and crisper vision, particularly better night vision. Although many laser centers only use Wavefront technology for some of the treatments, at the Caster Eye Center, we use the Wavefront technology for all of our treatments!

How does Wavefront laser vision correction do this? The eye has many minor imperfections that are not corrected by glasses or contact lenses. These are known as higher-order aberrations. Wavefront technology is computer software that allows us to correct for some of these imperfections. Vision after Wavefront treatment is often better than it was with glasses or contact lenses

Issues with night vision, particularly increased night halos and night glare, remain the primary complaint after Lasik laser vision correction. Wavefront Lasik treatment performed with the Alcon Wavelight Allegretto laser has been proven to create better night vision on average than existed prior to Lasik treatment with glasses or contact lenses. Importantly, the Allegretto laser with its version of Wavefront technology is the only laser system that the FDA states improves night vision on average beyond the vision experienced with glasses or contact lenses. Better night vision, particularly regarding night glare and night halos, after Lasik without glasses than you had prior to Lasik with your glasses or contact lenses. This improvement only occurs with the Wavefront technology of the Alcon Wavelight Allegretto laser system — no other laser system is able to achieve this improvement in night glare and night halos. This is an extremely important feature, and is the primary reason why we choose to use the Alcon Wavelight Allegretto laser system for all of our Lasik and PRK treatments.

All treatments at the Caster Eye Center are Wavefront treatments using the unique Wavefront technology of the Alcon Wavelight Allegretto system.

The information below shows how patients compare their night vision after Wavefront Lasik treatment with the Allegretto laser (of course, without any glasses) to their vision before Lasik treatment with glasses or contact lenses:

 GlareHalosNight DrivingFluctuation of VisionDouble VisionBlurring of Vision
Custom lasik vision (with no glasses) is better than previous vision with glasses or contact lenses11%12%11%10%11%14%
Custom lasik vision (with no glasses) is the same as previous vision with glasses or contact lenses89%88%88%90%87%86%
Custom Lasik vision (with no glasses) is not as good as previous vision with glasses or contact lenses0%0%1%0%2%0%
Daytime vision is also, on average, better after Wavefront Lasik than with glasses or contact lenses

20/16 or better -> 68%     |     30/30 or better -> 96%     |     20/25 or better -> 99%

Which laser treatment is best for me?

The most popular variation of laser treatment is called Lasik. Other names include IntraLasik, Femto-Lasik, and all-laser Lasik. In this technique, the laser treatment is made within the cornea, rather than near the corneal surface. This is accomplished by using a laser to create a protective flap in the front 20% of the cornea and then applying laser treatment to the tissue beneath the flap.

The vision correction treatment can also be applied near the surface of the cornea (instead of under a protective flap), in which case the technique is referred to as Advanced Surface Treatment. This technique has several minor variations, which include PRK (for “photo-refractive keratectomy”), Lasek, and Epi-Lasik. In PRK, the thin layer of soft tissue coating the outside of the eye (the epithelium) is removed and the laser energy is applied to the firm tissue underneath. In Lasek–with an “e”–the soft tissue on the surface is replaced after the laser treatment. In Epi-Lasik, this thin layer of soft material is folded back using a machine. PRK, Lasek, and Epi-Lasik are very similar to each other. When the laser treatment is applied to the tissue deep within the cornea (as in Lasik) instead of near the surface (as in Advanced Surface Treatment), the healing is quicker with more rapid vision recovery.

Smile Lasik is “small incision” laser correction. A laser is used to create a thin, lens-like layer within the cornea, as well as a narrow tunnel to the surface. The doctor reaches in to separate and remove the lens through the tiny tunnel.

Patients usually see very well the next day after Lasik. In Smile, the intial healing takes a few days, and in PRK the intial healing takes about a week. Complete healing takes about three months with all three techniques.

The visual results are the same with each of the versions of laser vision correction. The technique that is best for you depends on your very particular eye measurements, lifestyle, and visual needs. You will be able to discuss this and any other questions that you have when you meet with Dr. Caster during your personal consultation.

laservisionLaser vision correction does not stop the eyes from the natural changes that can occur over time. For most people, the results of laser vision correction will last for their entire lives. But a small number of people, estimated at around 5%, will undergo a small lessening in distance vision over time. For these people, laser vision correction can be performed again to further improve the distance vision. Also, as people age past the age of 45-50, the near vision continues to worsen (“middle age eyes,” or presbyopia). We do not have a cure for presbyopia. Some people choose to deal with presbyopia by wearing reading glasses or progressive glasses. Others choose blended vision, in which one eye is adjusted for near vision or mid-range vision using contact lenses or with laser vision correction. Even if you had laser vision correction at a younger age, you can typically in the future have a repeat laser vision correction to adjust one eye for close-up or mid-range vision if you so desire. If you have blended vision with contact lenses, then we can create blended vision with laser vision correction. If you already have blended vision with laser vision correction, and the near vision has gotten worse, a repeat “tune-up” laser vision correction can typically be performed to further improve the near vision. Some people obtain very good vision after their first laser vision treatment, and are typically not wearing glasses or contact lenses for distance vision anymore, but the vision is not as good as possible. This group is around 10-15% nationally, but at the Caster Eye Center is only 4% (one in 25 patients). These people are suggested to have a tune-up procedure after full healing is complete, which is typically three months after the original treatment. At the Caster Eye Center, there is no additional charge for this type of enhancement treatment, as long as it is performed within 18 months of your original treatment. Most of the people who are waiting to have this type of enhancement treatment are not wearing any glasses or contact lenses for distance — the vision is quite good, but not as good as we can make it.

RK (radial keratotomy) was a popular form of vision correction before 1995. With radial keratotomy, multiple incisions were made in the cornea to correct nearsightedness with or without astigmatism. No laser was used in RK treatment. Although the RK treatment eliminated the need for glasses or contacts, it was not as accurate nor as easy as our current laser treatments.

People with previous RK will sometimes experience a change in their vision as they age, with the new development of farsightedness, nearsightedness, or astigmatism. This new vision problem can be corrected with laser vision correction, using either the Lasik or the PRK technique.

Dr. Caster has corrected the vision of many hundreds of people with previous RK. The treatment laser must be programmed in a slightly different fashion to obtain the ideal correction, but with this modification, the results of laser vision correction in people with previous RK are very positive.

contractsCataracts are a clouding of the lens inside the eye, resulting in a clouding of the vision. Cataracts are not caused by laser vision correction, nor are they treated with laser vision correction. Cataracts also cannot be treated with glasses or contact lenses. If the cataracts are mild and are not affecting the vision to any significant degree, then no treatment is required. If the cataracts are significantly negatively impacting the vision, then the treatment is to remove the cloudy lens from within the eye (cataract extraction) and replace it with a new artificial lens (lens implant). Sometimes after cataract removal, glasses are still needed for ideal distance vision. In these situations, laser vision correction can be easily performed to improve the distance vision and eliminate the need for glasses for distance vision. Of course, if the vision is hampered by other problems, such as macular degeneration, then laser vision correction will not be helpful.

In 2008, the FDA conducted a highly publicized review of quality of life following Lasik laser vision correction. The Caster Eye Center was proud to be selected by the non-profit Council for Refractive Surgery Quality Assurance, a patient advocacy group, to participate in a national survey for this important FDA meeting. Our office was one of six throughout the United States, each selected for its outstanding reputation, to participate in this confidential survey of 1,800 Lasik vision correction patients. The patients were selected at random and the results were confidentially obtained and tabulated by the Council for Refractive Surgery Quality Assurance.

The study showed that more than 99% of patients reported their overall quality of life to be as expected or better than expected after laser vision correction.

Some additional results of this post-treatment, confidential survey: (Patients were asked to rate results as much more/better than expected, more/better than expected, as expected, less/worse than expected, and much less/worse than expected.)

96% wear corrective lenses as often as expected, less than expected, or much less than expected.

96% report post-treatment vision without lenses as expected, better than expected, or much better than expected when compared to pre-treatment vision with glasses or contact lenses.

7% report side effects, none of which were more than seldomly problematic; 91% of these patients who report side effects said they would have the treatment again.

In the patients treated by this select group of doctors, 0.4% — only one in every 250 patients – would not recommend the LASIK treatment to a friend. Although we wish that we could make this number zero, and we are trying, I still think that this is an exceedingly small number of people who are not adequately satisfied. This is an extremely low dissatisfaction rate compared to other types of medical procedures, or other types of activities in general.

The two main problems reported by these laser vision patients were feelings of dryness and night vision issues such as halos and glare. Of course, many people have difficulty with dryness and night vision problems prior to laser vision correction when using their glasses or contact lenses. Our goal is to not make the dryness and night vision problems worse, or even to improve pre-existing dryness and night vision issues compared to glasses and contact lenses. Both of these side effects, in our experience, are typically temporary and are largely preventable on an ongoing basis because of the latest advancements in the technology and by matching the right patient to the right procedure.

Unfortunately for patients, the average laser center results are not nearly as good as our results. Patients need to spend more time selecting an excellent doctor and not be swayed by low prices. Low price equates to lower quality equipment and personnel, less intensive screening testing, and a less exacting attitude, with resulting lower quality visual results.

The above survey shows the results that we at Caster Eye Center are able to provide for our patients who choose Lasik. Los Angeles patients are thrilled to experience the best treatment possible. We are proud that Caster Eye Center was chosen as one of the top sites in the nation to survey for this important FDA evaluation. We are proud of the work we do and of our results.

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