LASER VISION CORRECTION PROCEDURES
Envision Laser Centers offer multiple laser vision correction procedures because every individual is unique. Age, sex, occupation, health, eye characteristics, etc., all can account for the procedure that may suit you best. That's why we recommend a FREE personalized LASIK consultation to discuss your personal attributes and goals to see if any of our laser vision correction procedures will benefit you.
LASIK
LASIK has made many advancements since the first procedure performed in the U.S. in 1991. Twenty years later, LASIK has evolved into one of the safest and most popular elective surgeries ever. In over 15 million procedures world wide, no one has ever reportedly gone blind from LASIK. Our LASIK procedure is fast and painless, usually taking about ten minutes for both eyes. Vision recovery is so fast, that most people are seeing well enough to drive the very next day!
LASIK stands for laser assisted in-situ keratomeluesis, and uses the cool beam of the excimer laser to reshape the cornea in a matter of seconds. To begin the LASIK procedure, a few anesthetic drops are used to numb the eye. Next, an eyelid holder is used to gently hold the eyelids open during the procedure which keeps you from blinking. Then, a device called a microkeratome is used to create a thin flap (usually 130-160 microns) containing the outer layer of the cornea, called the epithelium. During the flap creation you may feel a little pressure and your vision will fade out for approximately 15 seconds.
After the flap is made, you will be instructed to stare at a blinking light, while Dr. Patel engages the cool beam laser (in most cases between 30-45 seconds). Dr. Patel will continue by repositioning the flap and administering antibiotic and steroid drops before the lid holder is removed (you will continue with those drops four times a day for seven days). You will be able to sit up and see better than prior to surgery, but vision will be moderately hazy. The haziness dissipates hourly, and by the next morning, you will be amazed at how well you can see.
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Custom LASIK 
Custom LASIK differs from traditional LASIK by using light waves to map out thousands of points to detect abberations in your cornea. Treating higher order abberrations which can significantly reduce night time glare and sharpen poor night time vision. Studies show that almost half of Americans suffer vision problems while driving at night.
Your eye is as unique as your own fingerprint, with its own special shape and complex characteristics that make it unlike any other. The best treatment is one that is unique to you. To better understand your particular vision and any impairments you may have, the Zyoptix(TM) system maps thousands of data points -- producing a fully detailed, three-dimensional picture of your cornea's shape and characteristics. Your doctor can then provide a unique treatment for each eye, resulting in personalized vision correction that is as individual as your eye.
Small imperfections in the shape of the eye can cause a scattering of light, which in turn can contribute to vision impairment. This scattering of light forms distinct patterns within the eye known as aberrations. The innovative design of the Zyoptix(TM) personalized laser vision correction system allows your doctor to measure these aberrations, then plan a treatment that exactly matches the eye's individual vision errors. Custom LASIK will provide minimal benefits for people with minor aberrations. Our doctors will examine all information to determine how Custom LASIK may benefit you.
PRK
Photo Refractive Keratectomy (PRK) is a surface ablation procedure (meaning no corneal flap is made) and is considered the safest and most accurate form of laser vision correction.
Surface ablation procedures do not alter the interior structure of the cornea, because no corneal flap is made. The laser reshapes the cornea directly under the epithelium, which is the outer-most layer of the cornea. Surface ablation procedures are the safest form of laser vision correction. Making a corneal flap, even with a laser such as Intralase, still increases the chance of complications such as infection, double vision and epithelial ingrowth to name a few of the different kinds (chances are normally less than .1%).
In the above video, the first step of PRK is inserting a punctal plug into the tear duct to keep the cornea hydrated post surgery to promote propper healing and comfort. After the lid holder is in place, a special mixture comprising mainly of BSS is placed on the cornea for 30 seconds to weaken the epithelial bonds. The epithelial layer is removed and the laser is applied to reshape the cornea. A protective contact lens is then placed on the cornea while the epithelium regenerates (usually in about 3-4 days).
Most people have functional vision and very little discomfort the very next day. Most people are usually able to drive in about 4-5 days following their PRK procedure. With today's advancements, many doctors are finding that PRK is often a better option for patients than LASIK.
BLADELESS LASIK
Today, LASIK flap creation can be performed with either a precision device called a microkeratome or a femtosecond laser. Of the leading methods of flap creation, the Bausch & Lomb Hansatome® microkeratome is the nation's most widely used. Known as the "gold standard" of flap creation, the device has been used in more than eight million procedures worldwide.
A femtosecond laser such as Intralase®, creates bubbles in the cornea, which help separate the flap from other corneal tissue. This so called "all-laser LASIK" actually requires the use of a hand held metal instrument to separate and pry the flap open.
LASIK surgery with the Hansatome® microkeratome is in most cases three to four minutes faster than with the latest Intralase® device. A faster procedure means less anxiety for patients. Also, many surgeons acquired Intralase to make ultra thin flaps to preserve tissue, but the thin flaps sometimes allow the bubbles to penetrate the flap in essence causing a "button hole" effect which can cause affect your final outcome.
Studies at two prestigious research institutions, the MAYO Clinic in Minnesota and STANFORD University in California, concluded that the Intralase® technique provides no improvement in results over the Hansatome® microkeratome.
As of January 1, 2008, less than 25% of all current U.S. LASIK procedures were performed by using Intralase. So what really are the advantages and disadvantages of IntraLase?
The main advantage of using IntraLase is in the event of a partial flap (a partial flap is an incomplete corneal flap which happens very rarely). If an actual partial flap occured with Intralase, you only have to wait an hour to attempt another flap. With a mechanical microkeratome, you must wait 3 months in order to make another flap. Other advantages may include more variable flap thicknesses and fewer corneal abrasions.
The main disadvantage of Intralase is the additional cost of $300-$500 per eye the IntraLase commands. With the chance of creating a partial flap by most microkeratomes in a skilled surgeon’s hand being well under one in a thousand, and the fact that multiple heads can be used to provide different flap thicknesses, most surgeons opt for using a mechanical microkeratome versus the IntraLase. If a person is hesitant about any of the risks associated with making a corneal flap, PRK is an option that should be discussed with the surgeon.
PUNCTAL PLUGS
The most common side effect after LASIK is temporary dry eyes which can affect comfort and vision shortly after LASIK. Punctal plugs are the easiest way to avoid dryness issues.
 Most studies suggest that between 75-80% of LASIK patients have some form of dryness after surgery that can last from weeks to months. Dry eyes may affect your vision after surgery and may increase your risk of regression after surgery. Your eyes need lubrication from tears to help them heal after surgery. There are two ways to combat this dryness.
One way is to use preservative free artificial tears hourly for two weeks following surgery and to use them as needed in most cases until three months post-operatively. In some cases it may be as long as a year, especially in older individuals or individuals with pre-existing dry eye conditions (patients with an existing severe dry eye condition should not undergo LASIK until the condition is remedied).
The second way is by inserting very small dissolvable punctal plugs into your tear ducts. The tears that individuals produce escape by evaporating or draining through your tear ducts (which is why when you cry your nose runs). By preventing your tears from draining, they remain on your eye with their natural antibiotics to aid in healing. You cannot see or feel these plugs and in about three months they dissolve and your tear ducts are back to normal.
There is nothing wrong with using artificial tears, but you must be regimented enough to use them hourly. Artificial tears must be preservative free (preservatives can be toxic in high doses) for the first 30 days. The use of these tears can be almost as costly as having punctal plugs inserted.
LASIK evolves with technology and punctal plugs have been shown to decrease regression after surgery, reduce vision fluctuation, increase comfort and minimize the possibility of flap slippage after surgery. Our doctors will be more than happy to discuss each individual’s case independently, because some people may be more susceptible to dryness after surgery than others.
Envision Laser Centers recommend punctal plug insertion on the day of your surgery rather than insertion after dryness is present. It is much easier to keep the cornea moist than to rehydrate a dry cornea (much like it is easier to keep a swimming pool full of water than it is to fill the pool when it is empty). By inserting punctal plugs, you are helping to ensure adequate tear film to promote proper healing.
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MONOVISION
The use of one eye for distance and one eye for near vision is referred to as monovision and is one of the options to consider as part of your refractive surgery decision if you are over the age of 40.
Monovision has been used successfully for over 25 years with contact lens correction and with various types of refractive surgery. By correcting one eye to focus in the distance and one eye to focus for near, the vision part of our brain tends to suppress or filter out the image from the eye that is not in clear focus. The patient is not bothered by the eye that is not in focus. Monovision is not the best of both worlds, but for many people such as lawyers and reporters who continually focus back and forth between close and distance objects, monovision provides the best alternative for accomplishing their goals.
Frequently Asked Questions About Monovision
The change in accommodation (focusing ability) to see objects at near will generally begin to decline around the age of 40 and will usually get worse quite rapidly over the next 10-15 years (presbyopia). Presbyopia, loss of ability to change your focusing distance from far to near, will occur whether or not you have refractive surgery. This is the reason people over the age of 40 generally need magnifying glasses (readers) to see up close. There is no right or wrong answer to the question of whether to have monovision. This information is to help you make this decision.
As a rule, we suggest against monovision if you are under the age of 35 for two reasons:
- It will be a number of years before you will notice any benefit from it; and...
- It is very possible that there will be a better (or at least as good) surgical way to help presbyopia by the time it is a problem for you.
We also generally recommend against monovision at any age for people who may need to see better than average for distant tasks. Some examples might be pilots, race car drivers, someone who drives for a living (especially at night), and avid tennis players (especially for playing at night), etc.
In our experience, most people over the age of 40 to 45 who try monovision and take a few months to become accustomed to it, like it and find it very useful. Those who have monovision will be able to generally see well enough both at distance and near to do most things at any age without corrective lenses. Depending on the exact result obtained (as is true for everyone having refractive surgery) there might still be some situations when the very best vision or the maximum visual comfort might require wearing glasses (or possibly contacts). Night driving and prolonged reading are two examples that are mentioned frequently, but it could be anything for which you feel the need or desire to see the very best possible. It is probably helpful to realize that without a specific cure for presbyopia, once you are past the 40 year age range, all refractive corrections involve compromise. If you have both eyes corrected for good distance vision, you will need glasses for close vision. If you have both eyes corrected for close vision (not a common choice) you will need glasses to clearly see everything far away. If you choose monovision, although your vision may work well for almost all purposes, you might feel it is less than perfect.
We know of no perfect way to help you make this choice. We would suggest that if significant doubt remains in your mind, that you aim to have your vision corrected for good general distance vision and plan to use reading glasses when necessary.
It is important to note that if you choose monovision and are unable to get used to it, it can be reversed by performing an "enhancement" procedure on the eye made to see near. Once the enhancement is performed the near eye then sees more clearly in the distance and reading glasses are then required for all near tasks. Below you will find the answers to frequently asked questions about monovision. If you have any further questions regarding your care, please contact us.
MONOVISION FREQUENTLY ASKED QUESTIONS
If I choose to have monovision, does that mean I will never need reading glasses?
No. Presbyopia continues to worsen as you get older, whether or not you have monovision. At some point, the presbyopia may be so bad that reading glasses will be necessary. Still, there is a benefit to having the monovision because there won't be a complete dependence on glasses for things up close. Larger print will still be readable without glasses, and things slightly farther away (like computers and dashboards of cars) will still be readable. Without monovision, even these things would be blurry without reading glasses. For this reason, patients usually don't "give up" their monovision as they get older. They still read better with the monovision than they would if both eyes are corrected for distance, even though for certain things, reading glasses become necessary.
What will the vision be in my reading eye with monovision?
The distance vision in the eye set for reading will be less than 20/20 for distance. The reading eye is left slightly near sighted to allow for better close vision. The amount of residual nearsightedness may be different for different patients, depending on age at the time of surgery, how "good" the patient wants the reading to be, how much distance vision they are willing to give up, and how long they want to be able to read before they eventually need reading glasses. Typically, the amount of nearsightedness left will be between -1.00 and -2.00 diopters. On average it is -1.50 diopters. Regardless of how many residual diopters of nearsightedness are left to allow for the monovision, the vision on the eyechart cannot be predicted just by looking at this number. There is no conversion between diopters and visual acuity on the eyechart (20/20, 20/30, etc.). In other words, if you are left with -1.50 diopters of residual nearsightedness you may see 20/40 with that eye in the distance, or you may see 20/100, 20/80 or 20/50. It can be and is different for different people. In any case, it is not really important how each eye sees separately, it is a two eye world and what is important is how you see with both eyes open you and are you able to comfortably see both near and far for most of your needs.
I tried monovision with contacts and didn't like it. Will it work better with surgery?
It may, and it may not. Part of it depends on how it was tried with the contact lenses. Was it tried for a day, or for a month or more? Sometimes it takes awhile for the brain to "adjust" to this way of seeing. Were the contact lenses properly fit? Was the proper eye set for distance? Was there any astigmatism that needed to be corrected that wasn't with the contacts? Even if everything was done "right" there is certainly a chance that monovision didn't work well. Some of these people have gone on to have surgery, and have tried monovision with surgery and have liked it. Some still did not like it, even with surgery. There may be some contact lens problems that people attribute to monovision problems, and that is why some people may do well with it, even if the contacts didn't work well.
How do you decide which eye to do for distance and which for near?
There are several factors involved. One is, which is the dominant eye? Usually, but not always, the dominant eye is set for distance. Sometimes a patient will come in who has been wearing contacts for monovision and the dominant eye is set for near. If this has been done for awhile, and the patient is doing well with the monovision, we will keep it this way and correct the non-dominant eye for distance. Some patients have a large difference between the measurements in the two eyes. One eye may be -4.00 diopters and the other may be -8.00. Even if the -8.00 diopter eye is the dominant eye, we might make that the reading eye in order to minimize the amount of treatment each eye gets. Part of the purpose of the comprehensive eye exam is to look at all of these issues and decide what will work out best
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