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LASIK (laser in-situ keratomileusis) has become one of the most successful procedures to correct refractive errors, replacing glasses and contact lenses. There are no precedents for the number of procedures that are being performed Worldwide. Over one million eyes are being treated this year alone. The rapid return of functional vision, lack of discomfort, and the overall stability and accuracy of the treatment have led to this astounding success. The risk/benefit ratio for most patients exceeds that of contact lenses. Although the FDA has determined the excimer laser vision correction procedure as "safe and effective", there are still many critical factors that must be considered in order for each patient to achieve the best possible result. In LASIK, a thin flap of corneal tissue is created and folded back to allow access to the underlying stromal tissue (bed). With the stroma exposed, multiple 2mm pulses of cool ultraviolet light are applied in a computer-controlled pattern causing a photochemical reaction that evaporates a precise amount of the tissue. This results in the front surface of the cornea being reshaped similar to having a contact lens inside the cornea. With the correction now in your cornea, the light rays entering your eye are bent to focus correctly on the retina, improving vision.
LASIK is performed at our Center as an outpatient procedure, typically, on both eyes on the same day.
Upon arrival at our facility, you will be asked to thoroughly read and sign the surgical consent form. After completion of the necessary paperwork, you will be taken to our Pre-operative waiting room where you can relax and be "prepped" for surgery. You'll be given drops and a Valium if you wish to calm you and to help you sleep after the procedure. From here you will be directed to the laser suite. Anesthetic eye drops are used immediately prior to surgery to numb the eye. Using a special instrument, the eyelid is held open so you cannot blink during the laser procedure. The first step of the procedure involves creating the corneal flap. A ring is positioned around the colored part of your eye and a vacuum is applied to secure this ring. This pressure will dim the vision temporarily as blood flow is slowed to the retina for the few seconds it takes to make your flap. This brief dimming means you will not see the device come over your eye. The ring is removed and the flap is folded back to expose the stroma. The flap is then measured by the DGH Ultrasound machine to confirm its thickness. Based on these measurements, being within the safe and expected limits, we can now proceed to treat your eye with confidence that we will not be over-thinning your cornea. This step is left out of most center's care and is in our estimate critical in many cases. Read Dr. Foulkes article regarding this topic on the Ocular Surgary News site (article is from May 1, 2002). Once the bed has been shown to be smooth and the flap out of the way, a pupil tracking system is turned on to follow any movement of your eye during the brief time you are being lasered. You will be asked to look up at a red light. It is important to note that the Bausch and Lomb laser with it's large treatment zones achieved better results than other lasers without the tracker system and is simply reassuring to know it is working on our current version of this wonderful laser.
 When ultraviolet laser energy is applied to the stroma, a cloud-like plume of ablated tissue and water vapor is created. The Bausch and Lomb laser uses 2 mm spots that are scattered 50 times a second in two locations to create a precision shape on your cornea in seconds. It treats with 100% power usually out to the edge of your pupil size then 80% power for 2 mm further then blend out an additional several millimeters. The result is the largest sized treatments currently available but require a surgeon who is especially diligent about understanding tissue requirements. After the laser stops, the bed is then measured for thickness again, and saline water is used to float the flap back into place. The flap is gently pushed down by a special instrument in all directions for a few moments to insure that the two surfaces bind to each other. Finally, the eye is given steroid and antibiotic drops and then closed. The stroma tissue sticks to itself like Velcro, eliminating the need for stitches. The same procedure is then carried out on the other eye. You will sit up able to see a clock at the end of the room!
The vision is already altered but foggy from the fluid in the flap. This clears significantly after you take your nap at home. Immediately after the procedure, your eye feels "scratchy," but without pain. Because the outer corneal tissue of your eye is among the fastest healing in the body, recovery time is minimal. Nearly all patients achieve functional vision within 24 hours. You will learn a great deal about your vision and the LASIK experience at this web site. We are with you every step of the way and are committed to achieving your visual goals and to do our utmost to protecting your visual future. You can further increase your knowledge by calling or visiting us at Future Vision Laser Center. Because of our commitment to your visual health, Dr. Foulkes and his staff are always available to address any questions or concerns that you may have.
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Mild headache may occur or lid tenderness from the instrument that holds the eyelid open. (Also see Prolonged Surface Healing.)
Very common for the first 24 hours, so we will provide you with cool wrap-around sunglasses. These should be worn anytime you may be at risk of being struck in the eye during the first month after your procedure.
Commonly occurs within the first 2 to 4 hours and is sometimes heavy.
Nearly everyone is functional for his or her daily activities. Mild blurring may occur for several weeks for some people. This is most common for larger corrections and is also related to your age and dryness.
It is not possible to predict with absolute certainty how the eye will heal and respond to treatment. Any under-correction is usually mild and does not interfere with a patient's daily activities. If an under-correction is significant and there is enough underlying cornea (bed), you have the option of additional treatment also called an "enhancement" or refinement. Rarely, we get a small over-correction. In this case, the eyes are treated with medicinal drops, which can slightly reverse the correction to bring it back. Again at about 4 months we can correct this with laser or the CK treatment as necessary.
Sometimes occurs immediately following surgery, but does dissipate as the cornea heals internally. This is reduced or elimate by larger treatments and may actually improve night disturbance in some patients. Recent evidence implies that in many eyes the night problems are caused by a drop off in the power of the treatment as it move out toward its limit. This is magnified in smaller treatments. When eyes are seen on the orbscan after treatment with many lasers the effective area noted could be fewer than 5 mm. This is likely to be the cause of night problems and visual fluctuation. (See Pupil Size & Correction Zone)
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Every precaution is taken to avoid infection. It is critical that post-operative instructions and medications are followed and taken as directed. Although most corneal infections can be successfully treated, potential consequences include corneal scarring, perforation, and spread of the infection inside the eye. We currently use a drop that may be better able to kill a few very rare bacteria and by starting 3 days in advance you are building up a level in your cornea to protect you.
Significant corneal scarring is rare after LASIK surgery, but more common with PRK. Proper use of your post-operative medications is an important component in preventing this possibility.
LASIK involves the creation of an interface between two layers of corneal tissue. Epithelial cells (the corneal skin) can grow into this interface. This growth is usually mild and not noticed by the patient, nor does it have an affect on vision. In rare cases, these cells may continue to grow, creating thinning of the flap and astigmatism. The epithelium is a loose sheet under the flap and is removed with excellent prognosis in nearly all cases. We use a fiber optic light pipe to identify areas of growth and fully remove them. Normally only the edge of the flap is lifted and the vision remains the same even immediately following the treatment!
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This is a very important consideration in LASIK surgery. How much the pupils will dilate at night determines what size the zone of correction has to be on the cornea. If the pupil will naturally dilate beyond the zone of correction, the presence of halos and significant glare can occur.
The common way to measure dilatation is with a cobalt blue light in a dimly light room. This type of measurement is not always accurate, and may be up to 1 to 1.5mm under the actual maximum dilatation. For this reason, we here at the Future Vision Laser Center use an infrared pupil measurement in the dark using a handy cam. We will video your measurement after you have dark adapted (this is called scotoptic pupil dilation). This device assures that the "maximum dilatation" measurement is accurate. You do not get night disturbance in your vision when you are in the dark as there is no light and when there is light your pupil will react and shrink in size. However it is the only standard that we can use and if we can treat this larger size it is our opinion that we have reduced your risk of night vision problems. The other risk factor for this problem is the depth of the front part of your eye known as the anterior chamber and we will have this measurement from our Orbscan II device. View Measurement
The effective treatment zone size is important to give the best quality vision after a LASIK treatment. We are learning that many lasers under correct as they move out to the edge of the treatment. Even though the laser may claim to treat large the observed area of treatment can be very small. This is not true of the Planoscan software and the Zyoptics software of the Bausch and Lomb laser. By having a larger effective zone of correction and blending the two curves together with full power to the optical edge of your pupil, the possibility of halos and glare are greatly diminished and in some people the night vision may actually improve. In patients that currently have night vision disturbance we can likely eliminate or reduce the effect by providing a re-treatment that may only treat out at the rims of the treatment to expand and fully treat, where they were under treated on the primary treatment! This can be thought of as a refinement as it really is just a completion of the original treatment, which gives a huge pick up in night brightness and edge clarity called contrast sensitivity. This is really exciting knowledge that will take our already excellent results to the next level.
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