CLEAR VISION EYE CENTRE
 
 
Lasik
The VISX CustomVueTM LASER VISION CORRECTION

For everyone who has ever worn spectacles or contact lenses, imagine waking up to clear vision without the hassles and inconvenience of corrective lenses. This seemingly distant dream has today become a reality with the advent and success of CustomVueTM Excimer Laser Correction!

Down the ages, in their quest for good unaided vision, people have resorted to various refractive procedures. We have come a long way from incisional procedures wherein radial cuts were made on the front or the back of the cornea, which besides being unpredictable were also unsafe. These procedures have more historical than clinical importance today. The first Excimer Laser procedure, Photorefractive Keratectomy (PRK), which was a surface ablative procedure, had its own share of problems which paved the way for today’s most popular refractive procedure of them all – Laser in situ Keratomileusis (LASIK).

Ongoing improvements have occurred in the conventional LASIK procedure itself today due to refinements in the technique, instrumentation, software and technical aspects of the laser machines, which all add up to more accurate and safe procedures that translate into better visual outcomes for patients. In short, we have entered an era of customization in LASIK or the age of Super Vision!

What is Laser Vision Correction all about?
It involves reshaping the cornea, the transparent outermost covering in front of the colored portion of the eye with a laser beam to correct various refractive errors (focusing problems of the eye). In the earlier PRK procedure, the reshaping was done on the surface of the cornea, while in the LASIK procedure, reshaping is done below the corneal surface after a flap of clear cornea is created.

To understand how the laser works it is essential to know a little about the common focusing problems of the eye. Myopia or nearsightedness is the most common focusing problem, affecting a significant proportion of the Indian population. Nearsighted people can see various ranges of near objects clearly but not distant objects. Nearsightedness usually results from an eyeball that is too long. Hyperopia or farsightedness is a focusing problem caused by an eyeball that is shorter than normal. The effects of vary with age because of the diminishing flexibility of the lens. Astigmatism is the result of the general inability of the eye to clearly focus images from any distance. It results from uneven curvatures of the cornea. Instead of being spherical, it is more similar to the side of an egg. This focusing problem usually occurs along with nearsightedness, or farsightedness.

Over the years the LASIK procedure has evolved into a safe and effective operation. This procedure was recognized by the Food and Drug Administration (FDA) USA in September 1998. The VISX Company (AMO) are one of the pioneers in Laser Vision Correction and have introduced the gold standard in Excimer laser technology with their 6th generation VISX Star S4 Excimer Laser System. This FDA approved laser, which is the most popular Excimer laser in the US (70% of all excimer lasers being VISX) has performed more than 5 million refractive procedures worldwide, and has the most advanced technology currently available. This translates into greater accuracy of treatments, the highest degree of safety and excellent visual outcomes. The VISX Star S4 Excimer Laser has its software (CustomVueTM) for customized LASIK.

What is CustomVueTM LASIK, and how is it different from conventional LASIK?
The Food and Drug Administration recently approved a new technology that will change how your eye doctor views your vision problems. It's called CustomVueTM LASIK: the laser eye treatment is based upon the very unique visual characteristics of your eye. Until now, with glasses, contacts and conventional LASIK surgery, corrections were quite similar for each type of prescription — myopia, hyperopia and astigmatism.

CustomVueTM LASIK involves measuring the eye from front to back, using what's called "wavefront" technology, to create a three-dimensional (3-D) vision map. The information contained in the map guides the laser in customizing the treatment to your individual visual irregularities, beyond myopia, hyperopia and astigmatism. Prior to the advent of wavefront technology, two people with the same prescription would receive the same glasses, contacts or LASIK procedure. This captures unique imperfections in your vision that could not have been measured before. Like a fingerprint where no two are alike, your corneal shape is unique to you. This new level of measurement provides twenty-five times more precision than standard measurements used for glasses and contact lenses. This is similar to the difference between wearing an outfit picked up readymade off the rack, and tailoring it to one’s individual measurements for a better and more exclusive fit!

How much you see depends on what lower-order aberrations you have; lower-order aberrations are also called refractive errors and include myopia, hyperopia and astigmatism. Traditional LASIK treats these lower-order aberrations.and higher-order aberrations. This gives us treatment options that are truly individualized to one’s own visual needs.

Wavefront technology is groundbreaking because it has the potential to improve not only how much you can see, but also how well you can see.

“This means that the VISX CustomVueTM LASIK technology not only improves one’s unaided vision as measured by a standard 6/6 or 20/20 eye chart, it also enhances the overall quality of the image in terms of contrast sensitivity and fine detail. This translates into a reduced risk of post-LASIK complications, such as glare, halos and difficulty with night vision.”

“A significant proportion of patients have reported seeing better after the VISX CustomVueTM treatment than they ever did with glasses or contact lenses. In fact VISX FDA trials have shown that 98% of patients have achieved 6/6 or better vision without glasses.”

The Procedure
The procedure for both the conventional as well as the CustomVueTM LASIK remains the same. In performing LASIK, in order to ensure a painless experience, numbing drops are instilled in the eye a few minutes prior to the actual procedure; no injections are used. The surgeon first uses a special oscillating blade, called a microkeratome, to make a partial cut through one-fourth to one-third of the front surface of the cornea, creating a flap of clear tissue on the central part of the eye. The patient is then positioned under the Excimer Laser and asked to look at a flashing light. The laser is programmed to vaporize some of the internal corneal tissue under the flap.

The Excimer Laser is a unique type of "cold" laser (193 nm UV laser) that does not burn or cut tissue. Instead, it gently breaks the molecular bonds between the cells so that controlled amounts of tissue can be literally vaporized away, one microscopic layer at a time.

After the laser has removed the selected tissue, the flap is closed over the eye. The cornea has extraordinary natural bonding qualities that allow effective healing without the use of stitches. The patient is in the surgery suite for 15 to 20 minutes and can walk away after the surgery. No hospitalization is required.

After surgery, vision recovery is almost instantaneous, though blurry for the first few hours, but this gradually improves to normal by the next morning. Few patients may have a mild discomfort in the first two hours after the procedure. However, this is easily relieved by pain-relieving medication. Patients are encouraged to rest for a day after the surgery. Instillation of eye drops would start immediately after the surgery and will continue for approximately two weeks.

Most patients have functional vision and can resume normal activities and work the next day.

So, what are the risks and side effects of LASIK?
As with any surgical procedure, LASIK surgery has some possible risks and side effects that must be taken into account. A specific end result cannot be guaranteed, although it can be closely predicted based on data from thousands of previous cases.

Side effects are usually minimal following LASIK surgery. During the first few days after surgery, most people can expect to experience at least some light sensitivity, gritty and burning sensation in the eyes, slightly drier eyes,and increased or decreased response to laser correction. In most cases, these effects decrease, eventually disappear as the eye heals,or can be retreated with further laser. Serious complications are fortunately very rare. Some of these include infection or wrinkles in the flap both of which can also be treated with medicines and resurgery.

“These complications are minimal with the VISX Star S4 Excimer Laser System and the Amadeus II microkeratome with its host of inbuilt safety features. One of the unique features of VISX Star S4 Excimer Laser system is the Variable Spot Size (VSS) and Variable Repetition Rate (VRR)technology, which adjusts the laser beam size and placement according to the treatment, minimizing thermal effects and corneal tissue removal. This system removes the minimal amount of corneal tissue compared to other Excimer laser delivery systems, and allows safe correction of higher spectacle powers.”

“Another safety feature is its 3-D ActiveTrak Eye Tracking system along with the Iris Registration software, available on the VISX Star S4, allows the surgeon to place the laser treatment on the cornea with perfect accuracy despite eye movement during the procedure”.

A very important point to be kept in mind for safe LASIK, is strict adherence to the eligibility criteria i.e. being at least 21 years of age, having stable vision for at least a year, having corneas of adequate thickness and shape, free from complicating eye injuries and systemic diseases, and being off contact lenses for the required period of time.

Each patient must undergo a comprehensive series of eye tests and examinations for a detailed screening before consulting with the surgeon to discuss and plan the specifics of a personal vision correction. Having LASIK at a reputed and well-recognized eye clinic known for good sterilization and asepsis procedures, excellent maintenance of instruments as well as having the latest state-of-the-art laser and microkeratome technology, regular and vigilant post-operative follow-ups by qualified eye surgeons, all contribute to the safety of the procedure and keeping complications to a minimum.

For people with higher spectacle numbers and thinner corneas, a safe and new variant of laser vision correction called Epi-LASIK has arrived. This procedure is similar to the earlier surface ablation procedure Photorefractive Keratectomy (PRK) but with a difference…there is quicker rehablitation, minimal pain and complications, and great patient satisfaction. The corneal flap is made by a special attachment on the Amadeus II microkeratome, and is thinner and more superficial than the LASIK flap.

If you are unhappy with your glasses and contact lenses, it is important to take that first step and get yourself screened for suitability for undergoing Laser Vision Correction. A few questions often asked include:
  1. Are both eyes treated at the same time?
    Patients normally prefer to have both eyes treated at one sitting and get back to work faster. This practice is followed worldwide. Literature has shown that LASIK is an extremely safe procedure and sight-threatening complications are rare.

  2. Will the spectacle number get fully corrected at the time of LASIK?
    The laser is set so as to reshape the cornea to eliminate the number completely. However during the healing process the eyes of each person may heal slightly differently. Thus it is possible a small residual number may persist. Usually this does not make it necessary to wear glasses for routine work.

  3. Are the results of the LASIK procedure permanent?
    The correction of vision done by LASIK is permanent. However LASIK has no effect on the natural progression of the spectacle number. This is why LASIK is performed only in patients whose number has been stable for at least one year.

  4. If required, can LASIK be performed again?
    If the objectives of visual correction are not met with in the first surgery, a second, or enhancement procedure can usually be performed to provide additional correction. Most people do not require additional surgery, but the higher the amount of correction necessary, the greater is the possibility of needing an enhancement procedure. The surgeon and the patient together assess this need and make the decision about further surgery.

  5. Will reading glasses be required after LASIK?
    After LASIK surgery all distant objects are clearly visible. Since LASIK cannot arrest the normal aging process of the body, one may require glasses for reading at around the age of40-45 years. Sometimes it may be possible to correct one eye for distance and the other eye for near vision. This is called monovision. Today the software for presbyopic correction (distance as well as near vision laser correction) has been introduced.
Life-style benefits of LASIK Surgery
Laser eye surgery offers multiple benefits to most people with refractive errors. It is indeed a dream come true to have clear vision without the hassles and inconvenience of corrective lenses. No more excess baggage carting along lens solutions and spectacle cases on your fun weekend or holidays! Imagine having no more fears about being incapacitated in an emergency if lenses are lost or glasses are broken, and no more frantic phone calls to the eye clinic for replacement lenses or spectacle prescriptions.

“LASIK offers expanded career opportunities for police officers, firefighters, pilots, airhostesses and professional athletes and better vision for recreational sports, especially water, winter and contact sports. A testimony to this fact that the US Air Force allows pilots who have had CustomVueTM LASIK surgery done to fly fighter planes”.

“Having undergone Laser Vision Correction gives one a wider scope of peripheral vision than what glasses provide. For many people who could not tolerate contact lenses or who had to stay off contact lenses for extended periods of time due to recurrent allergic eye disorders, LASIK could be a safer alternative for their eye health than wearing contact lenses for an extended period of time.”


The eyes are indeed precious and vision is God’s own gift to mankind. Safety would be a primary concern. If you do qualify for the VISX CustomVueTM LASIK, you can avail of this new technology… safely, and experience a new visual freedom for all aspects of life.