LASIK, PRK, or IOLs: Which Procedure Will Be King?

Predict the unpredictable! Let us try to play this game and predict the future of refractive surgery. One of the most fascinating things that I have seen is the increasing possibility to offer a refractive procedure of choice for every patient. This is true customization: to fulfil our patients' individual needs and treat their unique optical characteristics. As you may guess, this includes—in the majority of cases—offering different surgical techniques.

I come from the cornea and anterior segment surgery field. When I became involved in refractive surgery, I promised myself that I would always try to learn the emerging surgical techniques. I did not want to limit myself only to LASIK, the dominant and current Holy Grail procedure. In recent years, we have been witness to several changes. The limitation of LASIK to treat low-to-moderate degrees of refraction, the rebirth of surface approaches, the expanding indications of phakic IOLs, the intraocular treatment of presbyopia with diffractive IOLs, the possibility of changing the shape of an altered cornea using a intracorneal implants or increasing its strength with the cross-linking technique, and the use of a new laser to create a corneal flap are just a few examples to point out that there are still different solutions to correct different problems. (See C-3 Riboflavin Treatments: Where Did We Come From? Where Are We Now? on page 36 for more information on cross-linking.) Not one single procedure can fix everything.

Once we have clarified these aspects of refractive surgery, could we decide on its king? I recognize that this may be too much for me! But, l will try to accomplish our Editor-in-Chief's wishes (and let me please take the opportunity to thank her for her confidence in my opinions). Herein, I will try to predict the medium-term future (ie, the next 5 years) of the proposed techniques, and I will try to reasonably choose one as king.

STANDARD SURGERY
LASIK may experience a deep change in upcoming years. Microkeratome flaps will progressively be replaced by femtosecond laser cuts, and when direct intrastromal ablation is a reality, microkeratome flaps will disappear completely. Five years from now, I believe we could see how procedures such as femtosecond lenticule extraction (FLEX), a technique proposed by Carl Zeiss Meditec AG (Jena, Germany) that uses the company's VisuMax femtosecond laser, may become a standard surgery to complement other surgical options.

Customization will become more than a nice word for marketing, and laser treatments based on wavefront, topographic, and biomechanic properties of the eye will become a reality. Surgeons will also have a better understanding of the cornea's biomechanic characteristics. Better diagnostic tools will be available, including optical coherence tomography (OCT) and improved devices to precisely measure the cornea. Such information will be linked to laser units to precisely focus the ablation depth.

The actual refractive treatment will probably be a mixture of the best properties from excimer and femtosecond lasers, and future platforms will combine both sources.

TRANSFORMATION
If LASIK—a two-step procedure of cutting a corneal flap plus stromal laser ablation—disappears because we will finally get rid of the flap and its inconveniences, will there be room for a surface approach? I may be wrong, but I like to think that conventional microkeratomes will still be used, however, they will be transformed into epithelial separators. One such example, and my preferred instrument, is the Epi Separator (Bausch & Lomb, Rochester, New York), a metallic separator used in a high-technology microkeratome.

Although we may still have to decide what to do with the epithelial sheet (I like to preserve the flap and limit the indications of surface treatment to myopes under -6.00 D, without the use of mitomycin C), it is clear that epithelial separators are faster, easier to use, and offer a higher-quality surface to treat very smooth and regular Bowman's exposure.

The surface approach has many excellent indications in addition to treating thin corneas, and it offers the best possible results in selected cases. Among the leading refractive surgeons in Spain, surface techniques represent 20% to 25% of total refractive procedures. If some improvements are made in recovery time, pain management, and discomfort treatment, this percentage will increase.

I have always been pleasantly surprised by the excellent results of two procedures: phakic IOLs for high myopia and LASEK in combination with wavefront-guided ablations to treat myopic eyes below -6.00 D. I have performed more than 600 cases of the latter. UCVA at 1 year was 0.98 ±0.15 Snellen, and it remained at 0.99 ±0.12 after 2 years.

Better knowledge of the biomechanic and optical properties of the cornea will allow us to decide on a surface or stromal approach for individual cases. The fusion of LASIK plus surface ablation will become a reality when femtosecond lasers can precisely cut at the basement membrane, monitored and guided by a high-resolution OCT or ultrasound device.

But what about presbyopia? Laser may be an option, but presently, I do not believe in its future: Have you ever seen the topographic aspect of a presby-LASIK–treated eye, at least with first-generation treatments? Can the wavefront-based option become a solution? I really do not know!

What is clear, then? IOL technology has taken a big step forward, and it is beating the laser approach for the moment. The progressive introduction of better diffractive IOLs with better aspheric and foldable properties will help microincisional surgery flourish. Optical results will be excellent, improving the performance at different reading distances and avoiding halos and glare. Toric and light-adjustable IOLs may also improve visual results and minimize undesirable postoperative residual refraction. I do not think that 5 years will be time enough to obtain the technology to replace lens content, which has been proposed in phaco-ersatz and other related techniques.

PHAKIC DIFFRACTIVE LENSES
Another option that should be investigated is phakic diffractive IOLs. This technology could be indicated in myopic and hyperopic patients aged over 45 years and would avoid more aggressive surgeries like clear lens extraction, especially in younger patients. Although these patients would require a second surgery for cataract formation, they could have a good result for a long time with a more conservative treatment option. I am now 46 years old, emmetropic, and dealing with presbyopia. I recently purchased 1.00 D reading spectacles (should I have bought 1.50 D?), and I have been trying monovision with a 1.00 D soft contact lens in my nondominant eye. Most of the time, I make an effort with what remains of my accommodative system, which means that I am really beginning to understand the problem.

If I were a high myope or a moderate hyperope, I would consider phakic diffractive IOL implantation to be a much better option than presbyopic lens exchange (ie, Prelex). And, I would not mind having a second surgical procedure for cataract extraction in approximately 15 years. I believe that many patients would consider this option if it were well explained. Although I regularly perform clear lens extraction following my own strict protocol, I never tell patients, "Try Prelex and you will have extra benefits, because cataracts are not going to be a problem anymore." I guess I missed out on that sales lesson.

Did I answer the initial question? I am afraid not yet! To be honest, I believe in the dual partnership of a king and a queen. Therefore, I must choose lasers and IOLs as the king and queen of refractive surgery. I believe in the combination of laser and intraocular surgery to cover a wide range of situations including differences in age, refraction, corneal characteristics, and lifestyle that would allow us to treat better our refractive patients.

As I previously mentioned: Who knows what procedure(s) will be king? The only thing that I can be sure of is that we will have a lot of fun reading these words again in 5 years' time!

Francesc Duch, MD, is from the Institute Catala de Cirugia Refractiva, in Barcelona, Spain. Dr. Duch states that he has no financial interest in the products or companies mentioned. He may be reached at +34 93 418 99 29; duch@icrcat.com.