Modern popular refractive surgery started with a microsurgical procedure called radial keratotomy (RK). Here, four to eight cuts are made in a spoke-like pattern in the peripheral cornea causing it to weaken and bulge out slightly. This in turn causes the central optical zone to flatten, simulating the effect of placing a concave lens on the eye.

RK actually had it roots over 40 years ago in Japan. However, it was only in the 70's, when the technique was improved upon by the Russian eye surgeon Fyodorov, that refractive surgery started to gain popular acceptance. But it never really took off in a big way as the results were often unstable and unpredictable. The healing process was also slow and painful.

 Laser refractive surgery was developed as a way to improve the accuracy and predictability of microsurgery. The advent of the excimer laser finally made this a reality. The laser was first developed and used way back in the seventies by the computer industry for the precise etching of computer chips. It was just the kind of delicate tool eye surgeons needed to sculpt the refractive power of the eye directly onto the cornea with precision and minimal damage.

The procedure was called photorefractive keratectomy (PRK) and the first cornea application of the excimer laser to the human eye happened in 1983. But it was only in the early nineties with treatment protocols and guidelines established that PRK moved beyond the experimental stage. Results for mild to moderate myopia were encouraging with 95% of patients seeing 6/12 or better post-op. 6/12 is the minimum vision requirement for driving in most countries. PRK slowly but surely began to overtake RK in popularity.

However, PRK never really took off in a big way as it took three days for the treated surface of the cornea to heal during which the eye is teary and painful. Vision was also unstable for the first few months with an initial phase of over-correction before the power finally settles down. Treatment of high myopia was also less than satisfactory with major problems of unpredictability and severe cornea hazing in some patients.

Then it was found that by using the laser to treat the deeper layers of the cornea, all these drawbacks could be surmounted. To achieve this, the excimer laser technique was combined with an established cutting technique called keratomileusis to create a superficial cornea flap. Hence we have the modern technique of Laser-In-Situ-Keratomileusis or LASIK. The first Lasik procedure was done in 1989.

Correcting Myopia

There is no true medical or surgical cure for myopia. This is because the process of eyeball elongation that occurs in myopia is irreversible. However, myopia can be corrected optically by placing a concave minus power lens of the appropriate power in front of the eye.

Spectacles wear is the oldest and by far the most popular method of correction. When correctly prescribed, it is harmless, safe and probably the most cost-effective method. However, spectacles wear has its many disadvantages particularly in high myopia. It is a hindrance in sports and many other outdoor activities. High power glasses look unsightly, feel cumbersome and are prone to cause spectacles intolerance.

Contact lens wear is the next most common method of myopia correction. They do not suffer from many of the disadvantages of spectacles. They are less cumbersome and do not fog up. They offer a larger and more natural field of vision. However, much time and money is spent in fitting, wearing and maintaining them. In the context of our modern fast pace lifestyle, the routine can quickly become tedious and tiresome. More significantly, contact lens wear can give rise to potentially serious medical eye disorders such as GPC and cornea ulcers.

The third method of myopia correction is through refractive surgery. It is the least popular method since it involves surgery. However, it still appeals to many as it offers the chance to do away with the downsides and inconveniences of wearing spectacles and contact lenses.

Patients with Extreme Myopia

Extreme myopia is debilitating

Lens implanation is a procedure that is suitable for the minority of eyes suffering from extreme myopia of over 12 Dioptres (1,200 degrees) or for those with accompanying cataract. Here, a small incision is made in the cornea and an artificial lens made of plastic, silicone or acrylic is implanted inside the eye, either in front of the natural crystalline lens or in its place. No stitches are used. Visual recovery is rapid and painless with the eye seeing well the next day.

Anterior chamber lens implant (in front of pupil)

Posterior chamber lens implant (behind pupil)

Possible Complications

It is important to be aware that as with all surgery, complications can occur. Serious complications are uncommon and occur in 1% or less of patients. Here is a list of the more common complications:

1. Under or over-correction

Due to individual differences in wound healing, under or over-correction is less acceptable than under-correction. While an under-corrected eye can still see well for near without lenses, an over-corrected eye will need lenses to see well for both near and distance. If significant under-correction has occurred, re-treatment may be recommended. For over-correction, treatment is difficult. For these reasons, most doctors will deliberately aim for a slight under-correction when doing myopia refractive surgery in patients with high myopia (near sightedness).

2. Loss of Best Corrected Visual Acuity

As a result of poor wound healing or cornea flap complications, irregular astigmatism, cornea scarring or haze may develop. The problem usually improves with time and use of steroid eye drops. Affected patients may suffer a drop in their best-corrected visual acuity. Usually the loss is limited to one or two lines of the standard vision chart.

3. Glare and Halos

Some patients may experience bothersome light sensitivity and glare or complain halos. The effect are usually most noticeable at night, when looking at light sources or in patients with large pupils. These can limit one's ability to drive, work or operate certain equipment particularly at night. The problem usually improves with time. However, the problems may persist indefinitely in some patients.

4. Contact Lens Intolerance

There is the risk that should you want to wear contact lenses after the procedure, they may not fit comfortably. This is due to changes in the cornea shape which affect how the contact lens sits on it.

5. Other Complications

The procedure may be aborted because of problems in creating a proper cornea flap. The cornea flap may dislodge soon after the surgery if there is trauma, rubbing or squeezing of the eyelids. Infections is one of the most feared complications as it can lead to cornea scarring and severe loss of vision. Poor epithelium healing can lead to recurrent cornea erosions or migration of cornea epithelial cells underneath the flap causing a "melting" syndrome. Retinal detachment and glaucoma have also been reported.