What really is LASIK?

The term is an acronym for  Laser Assisted in Situ Keratomileusis. It represents the simple technique of raising a very thin  microscopic flap of the clear membrane of the eye, the cornea  and then simply applying a gradated quantum of laser under the flap.

Why has LASIK become so popular all over the World?

LASIK has the big advantage that it is, for all practical purposes, A painless procedure. Following the completion of the entire procedure the patient may occasionally complain of a feeling like a hair in the eye & that too not too often. The feeling goes away in about 4 hours and after that, its simply progressive improvement of vision with virtually no discomfort.

How is LASIK done?

A super specialized little device called a Microkeratome is placed on the cornea and in literally 3 seconds can fashion a very thin perfectly transparent flap on the cornea. The patient only feels a little buzzing on the eye, and before he knows it, it is all over.

The flap is simply lifted up, rolled out of the way and the Laser is applied. The laser utilizes an ultraviolet light beam to very accurately remove the tissue from the cornea, literally resurfacing the cornea in the new shape desired which will eliminate the spectacle power. The flap is put back in place and the procedure is over.

What should I expect before, during, and after surgery?

LASIK is for all practical purposes a painless procedure though you will feel a little tightness and mild discomfort when the initial clip is used to open the eye lids, and when the Microkeratome makes your initial flap (though completed in 6 seconds flat with the new Carriazo Microkeratome.

Before Surgery

If you decide to go ahead with LASIK surgery, you will need to be evaluated in detail as to whether your eye is fit for LASIK surgery. This is termed as a “Baseline LASIK evaluation”.

It is mandatory that the use of contact lenses be discontinued and switch to wearing your glasses, full-time prior the initial examination, termed the “baseline evaluation”.

Contact lenses tend to change the shape of your eye. Especially if you have been wearing the lenses for a prolonged period of time. Especially with high powered lenses and RGP or hard lenses the cornea literally moulds itself to the shape of the lens. After the lens is removed the cornea gradually reverts back to its resting stage. If LASIK is done too soon the cornea will change in shape and lead to irregular results. It also produces inaccurate measurements which lead to an inadequate result. Often one is hasty in wanting to do a LASIK procedure fast and most contact lens wearers do not want to be seen in glasses but it is a wise precaution and makes sense.

The doctor will carry out a full eye examination including a retinal evaluation to be sure your eyes are normal in every way. You should be careful to tell him about your past and present medical and eye conditions, any history of trauma, infection, red eyes, hazy vision, and about all the medications you are taking or you may be allergic to.

What specific tests are to be done prior the LASIK procedure?

Computerized Corneal Topography:
The primary test. This instrument enables a very accurate map of the cornea to be plotted out almost  like the whorls and grooves of the fingerprint. This is individual to each eye and forms the basis of the entire procedure. The keratometer evaluates the cornea for any irregularity or any surface defect and looks for keratoconus or coning of the cornea which would preclude LASIK, with an automatic detection system.

The Optikon Scout Computerized Corneal Topographer utilizes a very sophisticated system which has an illuminated small cone with 28 mires (or lines) which reflect on the corneal surface and analyze almost 80,000 points on the cornea. It covers 90% of the corneal surface in normal eyes and has the resolution of +/- 0.01D with an accuracy of 1 micron.

It has a very sophisticated focusing device using a high resolution CCIR camera giving an superb Eye Positioning Control System (patented), automatic acquisition, with decentration correction.

This computerized map creation is the first step to doing wavefront controlled LASIK and is an important test.

Pacchymetry and Endothelial Cell Analysis:
The Topcon (Japan) SP-2000P captures the image of the endothelium cells and calculates cornea thickness by a unique non-contact operation, image acquisition can be obtain through contact lenses which allows the cell condition to be observed while fitting contacts. The system uses a very innovative 3D alignment  and auto capture system ensures perfect focusing, ease of operation and reliable results. It has a very fast cell measurement system and in less than one minute, a provides the cell count, and in the selected measurement area, gives the cell measurement results and displays the cells morphology, configuration and structure.

Abberometry:
Using the new COAS Shack-Hartman System a Helium-Neon laser is reflected and focused to the subject's retina for hardly 0.5 second. The laser reflects out from the retina through a series of very fine lenses (called lenslets) and is imaged on the computer. By measuring the difference between the beam going in the eye as compared to the one which has emerged, the aberrations (or optical irregularities) are measured and quantified.  Using the wavefront map generated by the computer to do a Excimer laser correction also called wavefront guided LASIK, gives the patient the best chance of achieving 6/6 vision as well as a improvement in quality.

During the LASIK Procedure

The entire procedure is very fast. You will be given a cap to wear and requested to lie under the Excimer Laser operating microscope.

Numbing drops will be put in the eye. You will be asked to keep your eyes shut as the outside of the eye is cleaned with Betadine (antibiotic) solution and then dried again.

As a next step a smooth clip will be placed to keep the lids apart. You will be asked to open your eyes as wide open as you can. There is no pressure on the lids at all.

Then a small suction ring is applied on the white of the eye to immobilize the globe at the time of lifting the very fine flap. You will only feel a little tightness, but there is no pain, or for that matter, even discomfort.

The new Carriazo Pendular Microkeratome is simply placed in the arms of the suction ring and for exactly 3 seconds it automatically moves forwards. You will feel a slight buzzing and then the machine reverses itself automatically to its initial position. The entire procedure is over in exactly 6 seconds. The instrument is lifted off, and the suction is released and the ring is removed. While the suction ring is on the machine is working on the front of the eye you will naturally not be able to see as the machine is in front of your eyes, but again its only for the 6 seconds.

The surgeon will lift off and fold the flap back. Next the red blinking light will be properly focused for you to see and the room will be darkened so you can focus on the light properly. When the surgeon is fully satisfied that you are fixating properly on the light he will tell you that the laser will go on. The laser makes a clicking sound and will stay on for anytime between 15 to 40 seconds depending on the power of the eye which is to be corrected. You will feel nothing.

Each individual pulse of the laser is designed to remove a very fine quantum of tissue. Since with wave front controlled LASIK, the data has already been fed into the computer of the Excimer laser, it will do exactly the correct amount and automatically stop.

The eye will then be well washed with a balanced salt solution, the flap aligned back into place and then a bandage contact lens is placed on the eye. The bandage lens makes sure that the flap exactly sits back into place and no dust or dirt can get in.

Antibiotic solution is then applied and the procedure for that eye is over. After both eyes are completed, you will be asked if you feel OK and then you walk out of the laser room with new vision.

What do Adam Clayton(U2), Brad Pitt, Tiger Woods, Jennifer Capriati, Brooke Shields, Cindy Crawford, Michel Schumacher, Sir Elton John, Eric Clapton, Richard Branson and many more sportsmen, actors, singers and celebrities have in common? They have all had LASIK and had their spectacle numbers eliminated.

Today, Sportspersons, Pilots, Boxers even  Navy Seals  and  even regular people from every walk of life are benefiting from  the new technology of LASIK to live a life devoid of a dependence on spectacles.

In 1987, two scientists Trokel and Srinivasan from USA found that the cornea could be reshaped with laser energy in order to remove the spectacle number. Thus laser refractive surgery was born. Today it (LASIK) is the most common surgical procedure in the USA, with more than 3 million procedures performed every year.

What’s the procedure for LASIK?
The eye doctor will check the spectacle power of the eye. If the patient is wearing contact lenses they should be removed for at least 5 days in the case of soft lenses and 1 week in the case of semi-soft GP lenses. That is because long term wearing of contact lenses leads to distortions on the surface of the cornea and an unstable number. If the doctor suspects an unstable number he or she may put eye drops to widen the pupil and check again. The retina also needs to be examined for weakness. Corneal thickness is checked with a special unit as also the shape of the cornea.

On the day of the procedure the measurements are all rechecked and fed into the laser. New technology allows us to maintain the natural shape of the cornea (prolateness) even after the laser. A small clip keeps the eyelids open. The eye is numbed with eye drops. There is no pain. A special machine called a microkeratome slices a very superficial layer of the cornea to a depth of 100 microns (less than the thickness of a human hair) The laser is applied under this. The eye is then washed. The clips removed and the patient goes home. On the day of the procedure vision is a little blurry like looking through a windshield with rain on it. The eyes may be a bit red and sore. However there is no pain. The next day the vision is clear.

What problems are common with LASIK today?
Patient satisfaction with modern LASIK is linked to explaining the limitations of the technology beforehand to the patient and not after the procedure.

A usual question is, "Doctor will my number go to zero?" In ideal situations yes however most patients are between +/-0.5 for which spectacles are not necessary. The object of the procedure is to remove a total DEPENDENCE on spectacles and to make patients spectacle INDEPENDENT which occurs 100% of the time. Any myope of -3 and up will tell you that the first thing they do on getting out of bed in the morning is to grope on the bed stand for their spectacles. LASIK totally eliminates this.

If the number is very high like a -8 or -9 and above, the patient may experience mild  glare at night and ring of light around street lights at night. This is a common occurrence but usually subsides in 2 to 3 months. Eyes may feel a little dry for up to a month but this too passes away. However the freedom experienced by the patient is something to be seen to be believed as they are no longer encumbered by spectacles.