Custom Laser Vision Correction

Implantable Contact Lenses
Natural Lens Replacement
Corneal Rings (Intacs)

Monovision
Full Distance Correction or Monovision?

Laser Vision Correction -- Lasik, IntraLase, and Lasik without a flap
Laser vision correction uses pulses of invisible, ultraviolet light to remove a microscopic layer from the front surface of the eye, changing the curvature of the cornea ever so slightly. To correct nearsightedness, the curvature of the cornea must be decreased -- the cornea must be made flatter. To correct farsightedness, the curvature of the central cornea must be increased, which is accomplished by removing a donut shaped ring of tissue. To correct astigmatism, the curvature must be altered in one specific direction.

Only a very small amount of material is removed, usually less than the thickness of a hair. Low amounts of nearsightedness, farsightedness, or astigmatisim will require smaller amounts of tissue removal, and larger corrections will require greater amounts. The total treatment usually takes less than one minute of actual laser time.

A computer running specialized software determines the exact pattern of pulses needed to remove the right amount of corneal tissue. The computer also directs the actual operation of the laser system.

There are several variations of laser vision correction, each of which has advantages and disadvantages. We perform all variations of laser vision correction. We will discuss your specific situation with you after we have taken your personal history and performed measurements and calculations. 

1. Lasik (laser in-situ keratomileusis). This is our most common type of treatment. A protective flap is made using the keratome or the IntraLase laser. The treatment is then applied under the protective flap. Lasik allows for the most rapid visual recovery. If you desire, both eyes can be treated at the same time.

2. Lasik without a flap (PRK, Advanced Surface Treatment, Lasek, Epi-Lasik). For patients with extremely dry eyes, thin corneas, large pupils, very high corrections or a combination of these, Lasik without a flap may be the best treatment. Rather than making a protective flap, the laser treatment is applied directly under the soft material (known as the epithelium) that covers the front surface of the eye. There are many minor variations in how the soft material is handled: if the soft material is completely removed, then the procedure is called PRK (photorefractive keratectomy); if it is replaced, the technique is called Lasek; if the soft material is loosened with a machine, then it is called Epi-Lasik. In any of these methods, the soft material heals in 5-7 days, during which time the vision is blurry and a protective contact lens must be worn. Sometimes both eyes are treated at the same time, though sometimes the eyes are treated 2-4 weeks apart. For more information about "Lasik without a flap", please click here.

In addtion, there are two types of treatment software that are available. Each of these software variations can be used with each of the flap variations discussed above: 

1. Custom. The treatment compensates for irregularities in the vision in addition to nearsightedness, farsightedness, and astigmatism. For more information about Custom Laser Vision Correction, please click here.

2. Conventional. The treatment is similar to the correction with glasses or contact lenses; one prescription is applied over the entire treatment area. For patients with thinner corneas, very high amounts of correction, or other combinations, this will be the preferred treatment.

Results
The vast majority of patients no longer need glasses or contact lenses for distance vision after laser vision correction treatment. Almost all patients who have laser vision correction see better without glasses after the procedure. After the initial treatment, 90% of patients will have 20/25 or better vision without glasses, and 99% will have 20/40 or better vision without glasses. 20/40 vision is good enough to pass the driver's vision test without glasses.

With the custom treatment, the results are even better: 96% of the patients achieve 20/20 or better vision without glasses, with 99% of the patients achieving 20/25 or better vision. For patients with mild nearsightedness, farsightedness, or astigmatism, the results are better. Patients requiring higher amounts of correction will have less accurate results. The general rule is: more accurate results will be obtained in people who require less treatment.

If needed, the results can be further improved through a repeat laser treatment. There is no additional fee to have a "touch-up" procedure. We perform enhancement treatments in 4% of our patients.

These results are very impressive, but it is impossible to tell you exactly what your results will be. No guarantees can be made about the outcome of laser vision correction in any individual case, because each person responds in a slightly different way. If you will only be satisfied with "perfect" 20/20 vision without glasses after laser treatment, then please do not have the surgery. Avoid any doctor or clinic that promises you a specific result, because that simply is not possible.

The quality of vision after laser vision correction is usually superior to vision with contact lenses or glasses. Patients generally have less glare than they had with contact lenses, and of course the inconvenience and discomfort of contact lenses is eliminated. Side vision isn't blocked, as it is with glasses, and there is no longer the problem of dirty, wet or scratched glasses.

Complications
Laser vision correction is subject to complications. The complication rate is very low and problems can usually be readily treated. Complications will be more common in patients with high amounts of nearsightedness, farsightedness, or astigmatism, because these patients require larger amounts of treatment. 

By far the most common complication of laser vision correction is under-correction or over-correction. This occurs because the patient absorbs slightly less or more of the laser energy than anticipated, or because the patient experiences an abnormal healing response. Further laser treatment, known as an "enhancement" or a "touch-up", can then be used, usually resulting in excellent vision without glasses or contact lenses.

Under-corrections and over-corrections are the main reason that all patients do not have perfect uncorrected vision after the initial laser treatment.

About 2% of laser vision correction patients will experience increased optical aberrations, including glare or halos at night. Every person, even if you have never had laser vision correction, to some degree has glare or halos when viewing a bright object against a dark background. Most people are not aware that they have glare or halos. You can demonstrate this to yourself by going outside, away from other lights, and viewing the moon; every person will notice a small glow or unevenness around the edge of this bright object. After laser vision correction, increased glare or halos is common during the first three months of healing. After the initial healing period, only a very small percentage of people will have more glare or halos than prior to the treatment, and a greater number of people will experience a decrease in the glare or halos. Large pupil size in low light in combination with a high amount of correction is more likely to result in increased glare or halos. Use of the newer lasers, with eye trackers and substantially larger treatment areas, has dramatically improved this problem. 

Many patients will experience dryness during the first weeks or months following treatment. Dryness is most common in people who have a lot of dryness prior to laser vision correction. Eyedrops or pills are used to control the dryness, which usually resolves by three months after treatment.

Complications affecting the health of the eye are extremely rare, but are possible. During the early healing phase, the eye is susceptible to infection. You will be asked to follow certain instructions, including using antibiotic eye drops. Carefully following these instructions will decrease the infection rate to far below 1%. Even if an infection does occur, use of antibiotic eye drops will almost always control the infection.

Steroid eye drops are very important after laser vision treatment, because they are used to control the healing response. However, if used improperly for too long, these drops can damage the eye by causing cataracts or glaucoma. It is very important to go to all scheduled follow-up appointments, especially if you are still taking steroid eye drops.

About 1% of laser vision correction patients experience some loss of best-corrected vision, which is the best vision possible when using glasses or contact lenses. About 2% of patients will experience an improvement in the best corrected vision. Of course, you probably will no longer use glasses or contact lenses for distance vision after the surgery, so you may not even be aware that your best possible vision is different.

Some professionals, such as commercial and military airplane pilots, care very much about their best-corrected vision. These pilots must have best-corrected vision of 20/20 in both eyes. If the best-corrected vision is anything but a perfect 20/20, the pilot's license will be lost.

A mild loss of best-corrected visual acuity might not even be noticed or might be just a minor annoyance. A severe loss of best-corrected visual acuity would be noticed by almost every patient and might make it hard to work in occupations that require fine vision. Severe losses of best-corrected visual acuity are exceedingly rare. Either an irregularity or a haziness in the corneal surface could cause a decrease in best-corrected vision. Short-term irregularities during the initial months of healing may occur in up to 5% of cases and almost always resolve as the healing progresses.

Re-treatments
Not all patients get a perfect result from laser vision correction. This may be due to under-correction, over-correction, or one of the complications described above. The most common problem is an abnormal healing response, resulting in under-correction or over-correction.

Patients who experience under-correction or over-correction can usually undergo a second procedure to obtain a better correction. In most cases, a significant improvement in the vision will occur, but it is important to realize that this, too, is a laser procedure, and therefore has the same risks that the first laser procedure had. It is possible but extremely rare that your vision can be worse after a "touch-up" procedure. Complications can occur, even if no complications occurred during your first procedure.

If your vision is quite good after your laser treatment, but not perfect, you should consider carefully whether you want to have a "touch-up" procedure. If your vision is really not satisfactory, then a "touch-up" procedure is a good idea. The enhancement procedures are quicker and easier to perform than the initial treatment. Overall, around 10% of patients undergo "touch-up" procedures. However, with the newer WaveLight Allegretto laser, the enhancement rate has been substantially decreased to less than 5%.

Which laser treatment is best for me?
The most popular variation of laser treatment is called Lasik (for "laser in-situ keratomileusis"). In this technique, the laser applications are made within the cornea, rather than near the corneal surface. This is accomplished by creating a protective flap in the front 20-25% of the cornea and then applying the laser treatment to the tissue beneath the flap. This protective flap can be made with a laser or with a keratome.

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, or "Lasik without a flap". 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. Patients usually see quite well the next day after Lasik. In "Lasik without a flap" the intial healing takes about a week. However, after the healing period is complete, the results are the same with each of these techniques.

Lasik requires an additional surgical step, which is the creation of the protective flap. The flap is created with an instrument known as a keratome or with the IntraLase laser. Creation of the flap takes about 15 seconds and is virtually painless. Complications with the flap occur about 1% of the time. Almost all of the complications are mild and can be easily treated, often by lifting or repositioning the flap. The most serious complication would involve improper creation of the flap; when this occurs, the patient is asked to wait three months, and then can return for a repeat treatment.

With either Lasik or "Lasik without a flap", there are two types of computer software that can be used, known as conventional and Custom. Both of these use the same laser to perform the vision correction treatment. The conventional software works like glasses or a contact lens; there is one prescription that covers the entire eye. Obviously, this produces excellent vision, just as do glasses and contact lenses. With Custom treatment, an additional modification is made in the treatment to account for additional irregularities in the vision.

On average, the wavefront (custom) treatments produce slightly better vision than the conventional software. However, the difference is subtle, not profound. In some situations, the conventional software will actually produce better vision than the wavefront treatment, so it is important that you are measured both ways, and that a decision is made based upon your individual measurements.

At the Caster Eye Center, we perform all of the variations of laser vision correction. All of the variations produce excellent vision. During your consultation, we will obtain measurements of your eyes, talk to you, and determine which procedure is the best for your specific situation. In this careful way, we obtain the best vision possible for our patients.

For more information about Wavefront-Guided Laser Vision Correction,
please click here.

For more information about "Lasik without a flap", please click here

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NearVision CK
NearVision CK, formally known as conductive keratoplasty, is a technique for improving near vision in people over 45 years old. NearVision CK is useful for a person who has always had good distance vision (or had the distance vision corrected with Lasik) and who is having trouble seeing up-close. This condition is known as "presbyopia", which means "old eyes". NearVision CK is the only procedure approved by the FDA for the treatment of presbyopia.

NearVision CK uses radio-frequency energy to change the curvature of the cornea. In NearVision CK, the energy is applied to the periphery of the cornea in sets of eight spots. As this peripheral tissue constricts, the central cornea steepens, resulting in an improvement in near vision. The procedure takes about five minutes, and the patient is able to sit up and see the results immediately. No injections of any kind are needed, though an oral medication is usually given to cause relaxation; the procedure is performed using eyedrops to numb the eye.

NearVision CK creates a form of monovision, which is known as "blended vision". In classic monovision, one eye in a patient over 45 years old is adjusted for near vision and the other eye for distance vision. A person over 45 years old who has excellent distance vision in both eyes can have monovision treatment in one eye, turning that eye into a "near" eye. This "near" eye, combined with the other untreated "distance" eye, will give the person both distance and near vision, which is referred to as monovision. Monovision can also be created using contact lenses, or with Lasik.

The "blended vision" of NearVision CK is similar to traditional monovision in some ways, but different in others. With NearVision CK, one eye will become the "near" eye. However, after the initial healing period of a few months, the "near" eye will regain some of the distance vision, and will be better for distance than in classic monovision. "Blended vision" is the name given to this modified form of monovision.

As with any treatment, there is variability in how each individual responds, and enhancement treatments are sometimes necessary after the initial healing period. Also, as each person gets older, the eyes will also continue to age, and additional treatment may be necessary to maintain the effect in 3-5 years.

To learn more about NearVision CK, please click here.

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Implantable Contact Lenses
Implantable contact lenses, also known as phakic intraocular lenses, phakic IOLs, or phakic implants, are tiny plastic or silicone lenses inserted inside the eye, behind the cornea. These lenses bend the incoming light rays and can correct higher amounts of nearsightedness.
   
Intraocular implants have been used successfully for many years to the replace the eye's crystalline lens when it turns cloudy, forming a cataract. To treat cataracts, the natural crystalline lens inside the eye is removed and replaced with an artificial lens. When used to treat nearsightedness, the natural crystalline lens remains inside the eye, and intraocular implants are placed in front of the crystalline lens. When the crystalline lens remains and an additional lens is placed inside the eye, that lens is known as a "phakic" lens.
   
Implantable contact lenses can be thought of as placing glasses or contact lenses inside the eye, to stay there indefinitely. This gives the eye another focusing lens to provide high-quality vision like a normal eye. One style of implant is placed in front of the iris (the colored part of the eye) and is attached to the iris at each end. This is the Verisyse lens (outside of the United States it is known as the Artisan lens). Because the lens is in front of the iris, it can be seen in the eye under normal conditions. Another lens, known as the Visian lens, is placed behind the iris. The Visian lens is not visible inside the eye except with the use of a special microscope. Our preference is to use the Visian lens.

Phakic IOLs are a more invasive treatment than laser vision correction. For this reason, implantable contact lenses are generally recommended for patients who are not good candidates for laser vision correction, either because the correction is too high or because the corneas are too thin. Certain physical characteristics of the eye may limit the ability to have phakic implants, including the size of the pupil (if too big, you could see around the lens, causing glare/halos), depth of the front portion of the eye, as well as the density of cells on the underside of the cornea.

The implantation of a phakic implant is done as an outpatient in an ambulatory surgery center, under local or topical (eyedrop) anesthesia. A small incision (a few millimeters) is made to allow the insertion of the implant. Most patients experience little to no discomfort during the actual procedure, which usually takes around 30 minutes. Remarkably, many patients report an instantaneous, dramatic improvement in their vision, similar to LASIK.

Implantable contact lenses can produce a very high quality of vision. If the lens is inappropriate for any reason (for example, if the vision in the eye changes), then the lens can be removed. Currently, the implantable contact lenses are limited to the correction of nearsightedness, but in the future astigmatism and farsightedness will be treatable as well. Presbyopia, which is the need for reading glasses, is not treatable with phakic lenses, though monovision is certainly an option.

For more information on implantable contact lenses, please click here.

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Natural Lens Replacement
Natural Lens Replacement is also known as Clear Lens Replacement, Clear Lens Extraction, or Natural Lens Extraction. The procedure is the same procedure as a cataract removal, except that it is performed in a patient whose lens is clear, rather than being cloudy (which is a cataract).

In Natural Lens Replacement, the natural lens inside the eye is removed and replaced with a plastic lens. The new plastic lens will have a more accurate focusing power than the old lens, enabling the eye to see more clearly. Usually, the eye is adjusted to see more clearly at distance, though the eye can be adjusted to see at near if desired. New models of plastic lenses are now available that allow for near or intermediate vision in addition to distance vision. These multiple focus lenses include the ReStor and ReZoom lenses, as well as the moveable CrystaLens. These lenses enable significant near or intermediate vision in addition to distance vision, but each has limitations, including halos at night, and the near or midrange vision is somewhat limited.

Natural Lens Replacement is a more invasive procedure than Lasik. Because it involves entering the inside of the eye, infection is a more serious risk. For patients who are extremely nearsighted, there is an increased risk of retinal detachment. In addition, the plastic replacement lens does not focus near and far as well as a younger person’s natural lens, though it may focus near and far better than a late 50, 60 or 70 year old's natural lens. Therefore, Natural Lens Replacement is usually reserved for people in their late 50s or older who are too farsighted for Lasik.

For more information about Natural Lens Replacement, please click here

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Corneal Rings (Intacs)
Corneal rings (also known as Intacs, intrastromal corneal rings, or ICR) are small pieces of plastic that are embedded in the edge of the cornea. The arc-shaped rings make the central portion of the cornea flatter, decreasing the amount of nearsightedness. Currently, corneal rings are available to treat only low amounts of nearsightedness, and treatments for astigmatism and farsightedness are still being developed.
    
By using rings of varying thickness, different amounts of nearsightedness can be corrected. However, corneal rings are made in only a very limited number of thicknesses, so they can only be used for very specific corrections. If the visual result is not ideal, or if the eye changes in the future, the corneal rings can be removed, but there might not be another ring that is appropriate to correct the vision.  In contrast, excimer laser treatments are available for a wide range of focusing errors and are easily adjustable with retreatments.

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Radial Keratotomy (RK)
Radial keratotomy was the first surgical procedure to be widely used to correct nearsightedness and, contrary to most people's understanding, does not involve the use of a laser. RK was invented in the Soviet Union in 1973 and was first performed in the United States in 1978. Over one million people around the world have been treated with RK. 
   
Like excimer laser surgery, RK corrects nearsightedness by altering the shape of the cornea. The doctor makes a series of incisions in the periphery of the cornea. This increases the corneal curvature slightly where the incisions are made, and decreases the curvature in the central portion of the cornea. The incisions are made in a radiating pattern, like the spokes on a bicycle wheel. By varying the number, length, depth, and location of these incisions, different amounts of nearsightedness can be corrected.
   
Although patient satisfaction with RK was very high, RK has now been largely replaced by excimer laser techniques and is seldom used today. Laser vision correction technology produces results that are more accurate than RK and can treat a much wider range of focusing errors. Because of this greater accuracy, excimer laser patients are much less likely than RK patients to require a "touch-up" procedure. Also, RK patients experience side effects more commonly than do excimer laser patients. These side effects include "starbursts" when viewing a bright light against a dark background and fluctuation in vision throughout the day. RK patients, but not excimer laser patients, experience a temporary, reversible fluctuation in vision when at high altitudes. Pilots, mountain climbers, and skiers may be affected by this and should not have RK. 

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Astigmatic Keratotomy (AK)
Astigmatic keratotomy is a variation of RK (radial keratotomy), used to treat astigmatism. AK uses arc-shaped incisions in the cornea, whereas RK uses radial incisions, like the spokes of a wheel. Neither RK nor AK is performed with a laser. At the Caster Eye Center, we do not perform RK or AK.
   
AK is often performed at the same time as cataract surgery, to correct astigmatism that the cataract implant is not treating. For mild or moderate astigmatism, AK's predictability is good but certainly not perfect. If astigmatism still remains after the cataract surgery, it often is more accurate to treat the astigmatism with laser vision correction than to use AK.

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Automated Lamellar Keratoplasty (ALK) 
Performed from the 1970s until the mid-1990s, ALK was the forerunner to Lasik. In ALK, a keratome was used to peel back the front layers of the cornea, creating a flap, just as it is used in the Lasik procedure today. No tissue is permanently removed in the making of the flap; by making the flap, it enables the doctor to work on the deeper tissue of the cornea. In ALK, the keratome was then used a second time to remove a small disc of cornea from under the flap, causing the central cornea to flatten and lessening nearsightedness. In Lasik, the tissue under the flap is instead removed using the excimer laser, which is much more precise. 
   
ALK has been completely replaced by Lasik and is not performed anymore. In fact, ALK was never very popular because the second part of the procedure, removing the disc of tissue, was not adequately precise. However, without ALK we would probably not have Lasik today. Lasik is a combination of the flap technique of ALK with the precision of the excimer laser -- a truly remarkable combination.
   
Because ALK has been performed since the 1970s, we have a long track record showing the safety of making corneal flaps. This is very important: because of ALK, we know that there are no long term safety problems from making corneal flaps.

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Full Distance Correction or Monovision?
As people approach the age of 40 – 50, they experience an aging change in which they begin to lose the ability to change their visual focus from far to near. This causes a decrease in the ability to see clearly at near, when the eyes are adjusted for distance. Thus, if you naturally have clear distance vision, then you will begin to need “magnifying glasses” for clear close-up vision when you approach 40 – 50 years of age. If your vision at distance is clear with glasses or contact lenses, you will not see clearly at near with your glasses or contacts on unless they are bifocals, or unless one eye is purposefully under-adjusted. You will generally need to wear bifocal glasses for near vision, although some people can remove their distance glasses and see well at near.  
   
For people approaching or in this age group, we must decide how to best adjust your eyes given this aging change. People who have already begun to use bifocals, reading glasses, or who need to remove their distance glasses for clear near vision usually understand this, though people who have not yet crossed this threshold sometimes find this confusing.
   
People often refer to this condition mistakenly as “farsightedness”. To be accurate, it is not “farsightedness” at all. The medical term is “presbyopia”, which comes from Greek and means “old eyes” (Since Dr. Caster is in this age group, we prefer to call it “middle-age eyes”!). This is the aging condition of the eye that makes near vision difficult, whereas “farsightedness” is an inherent (not aging) difficulty with close-up vision. Unfortunately, there is no word in English other than “presbyopia” that describes this condition.
  * From The Eye Laser Miracle: The Complete Guide to Better Vision  by Andrew I. Caster, MD, FACS

Three options are possible:

1. Both eyes can be fully adjusted for distance - In this way, the distance vision will be as good as technically possible. The patient will need to use reading glasses for good close vision, beginning sometime between the ages of 40 – 50. This could be referred to as the “normal” situation, because the use of reading glasses typically becomes necessary during ages 40 – 50, even for those who do not have laser vision correction.

2. Monovision - Monovision involves adjusting one eye for distance vision and one eye for near vision. Monovision is commonly used in contact lenses for people over 40 years old and can also be used with laser vision correction or other vision correction techniques.

In monovision, one eye will be used primarily at a time for ideal focus. If the object is far away, the “distance” eye will be primarily used. If the object is near, the “close-up” eye will be primarily used. Both eyes are used all the time, but one is generally primary, depending on the distance of the viewed object. Peripheral vision and depth perception are usually only minimally affected. Monovision is achieved by purposefully leaving one eye somewhat nearsighted. Usually, this is the non-dominant eye, such as the left eye in a right-handed person, or vice versa.

The main advantage of monovision is that patients over 40-50 years old often will not use glasses for distance or near vision. The main disadvantage is that the patient is relying on one eye at a time, and some people do not like this.

People with monovision may still use glasses in situations where they require excellent vision out of both eyes. For some, but not all, patients this may include driving a car (especially at night) or doing extensive reading. Other monovision patients will virtually never use glasses.

If a patient elects to have monovision and for some reason does not like it, the “near” eye can usually be adjusted to a “distance” eye with a touch-up procedure to eliminate the remaining nearsightedness. Once people have monovision and get adjusted to it (which may require a few weeks), it has been extremely rare for patients to elect to have it eliminated.

3. “Mild” Monovision – Mild monovision is a compromise between full distance vision in each eye and full monovision. In “mild” monovision, one eye is left with only a small amount of nearsightedness. This will cause only a small decrease in distance vision in one eye, but will aid somewhat in close-up and mid-range vision. For many patients 40-50 or older, this “mild” monovision is a reasonable way of dealing with the age related loss of adjustable focusing.

The degree of “mild” monovision is adjustable, based on age and visual demands. The patient can have good distance vision as well as good midrange vision without glasses. Midrange vision is very useful, such as viewing a computer or looking at faces during conversations.

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