Overview of the Different Types of Laser Eye Surgery

Imagine using lasers to reshape your cornea and get rid of your need for glasses. Not too long ago (well, kinda a while ago), this sounded like science fiction. But thanks to Lasik, millions of people have been able to live out this story! But first before we get to lasik, let’s go back in time to learn what existed before it.

What is RK?

Refractive surgery has gone through a large evolution throughout the years. Patients have always wanted to get good uncorrected vision with glasses or contact lenses. This was still true prior to the invention of the lasers we use nowadays for lasik and PRK. Without lasers, different techniques were developed to provide good uncorrected vision and at one point in time, the procedure of choice was called RK (short for Radial Keratotomy).

RK, when we describe it today, sounds kinda barbaric. The procedure is done entirely with blades! But, back in the days of RK, it was pretty effective for correcting nearsightedness and even some astigmatism. The procedure was done by creating multiple incisions (typically 4 to 16 incisions depending on the amount of prescription) in the periphery of the cornea. These incisions extended in a radial or spoke like pattern from the pupil. The result of this was that the center of the cornea became relatively flatter compared to the periphery of the cornea. And similar to how lasik works, having a flatter cornea reduces the amount of nearsightedness!

_{Spokes like RK; Image by Moyan Brenn from Italy / CC BY}

Many nearsighted patients were able to reduce their dependency on glasses with RK and many people were very happy with the outcomes to this day. But, RK was not a perfect. And eventually, PRK and lasik were able to steal the spotlight.

The Lasik Age

Lasik actually stands for laser-assisted in situ keratomileusis. Wow what a mouthful! But don't worry, it's not that difficult to understand.

The very front clear part of the eye is called the cornea. This is where all the magic occurs. The cornea has a very solid middle part called the stroma.

In lasik, laser is applied to the stroma to reshape and focus light where it needs to go. Fancy algorithms by the laser allow it to change the cornea just the right amount necessary in order to correct your prescription.

To get to the stroma of the cornea, another laser is used to open a nice clean window directly to the stroma (the lasik flap). This window is then closed and the eye heals up really quickly!

Does this take hours to perform? No! This is all done within a matter of minutes. Outstanding!

A close relative of Lasik - PRK

PRK or photorefractive keratectomy - lasik’s older brother. PRK in fact was developed earlier than lasik.

PRK works in a very similar fashion to lasik. In fact, both procedures use the exact same laser to do the actual correction! Well what is the difference you may be asking? The only difference between PRK and lasik is that PRK doesn’t create the “window” or “lasik flap” down to the stroma of the cornea. The treatment is applied to the surface of the stroma instead.

You will hear of many other procedures with the exact same principles as PRK (advance surface ablation, LASEK, Epi-LASIK, I know, confusing!) but they all share that same method of correcting vision without the need for a lasik flap.

This is great news for people who have corneas too thin for lasik. But sadly everything is not all roses and unicorns. Nothing bad longterm, but surface correction does take about a week longer than lasik for the vision to recover. But once recovered, surface correction works just as well as lasik to provide fantastic vision without glasses or contact lenses.

_{No glasses needed to see; Image by SheLovesGhosts / CC BY-SA}

Which Is Better: Lasik or PRK?

Lasik revolutionized vision correction surgery. However, result-wise, lasik didn’t change a whole lot. PRK was the standard of correction when lasik came onto the scene and lasik still uses the same laser to do the actual correction. The huge benefit that lasik offered was an almost immediate recovery! This made vision correction surgery very easy to get done and able to fit in to practically any schedule.

However, lasik does come with one key variable compared to PRK: the lasik flap. Fear of the lasik flap has led many to wonder which is a better procedure: PRK with the longer healing time, or lasik with the lasik flap.

_{Which way to go? PRK or Lasik; Image by Jonathan Billinger / Fork in the road / CC BY-SA 2.0}

Concern over the lasik flap isn’t new. However, fear of having a lasik flap isn't quite needed. Laser created lasik flaps are actually quite secure. Especially compared to lasik flaps created by blades.

In fact, there are only a few professions in which the lasik flap poses an actual risk. Namely those professions in which you are being hit repetitively in the eye (boxing, MMA, etc). For everyone else, the chance of something happening to the lasik flap is extraordinarily low.

Lasik technically is a slightly better procedure than PRK because of that quicker recovery. In PRK, the surface of the eye, epithelium, has to heal up over the course of the first week. Vision will take much longer with PRK to fully sharpen up. Thus, if you aren’t a lasik candidate and can only get PRK, it is still an awesome procedure. However, if you can get both, there isn’t a major reason to choose PRK over lasik. Unless, you simply just feel more comfortable getting PRK done. Ultimately, everything comes down to comfort level. The best procedure for you is the one that you feel most comfortable with.

Also check out Which Is Better, Lasik vs PRK? on EyeMountain.com to learn more

Newer innovations - SMILE

SMILE has gotta be the best name for an eye procedure!! What is there not to love? SMILE stands for SMall Incisional Lenticle Extraction. Ok, now to actually explain what that jargon means.

Lasers have benefited ophthalmology in quite a few ways. Lasik and laser cataract surgery are two prime examples. The laser used in these procedures, the femtosecond laser, is also used in SMILE. This awesome laser can precisely create shapes in almost anything. Shapes such as the lasik flap and shapes such as the capsulotomy or dividing up a cataract or lens in RLE.

To understand SMILE, first we need to learn a small bit of easy optics. The way glasses correct vision is by placing a lens in front of the eye to bend light to into focus. In short, lenses bend light and correct vision. But this same principle works in reverse. If you take away the proper shaped lens, light is no longer being bent out of focus but instead stays in focus. This is the principle behind SMILE. By removing a small lens which is causing light to be bent out of focus, you bring light back into focus again! The femtosecond laser is used in the cornea to shape the exact lens needed to remove and then it creates a tiny pocket in order for the surgeon to remove this lens! This lens is no longer needed and once recovered, you get clear vision without glasses! Makes you just wanna smile..

Related Articles