Refractive Surgery Beyond LASIK

New Advances made in Laser Eye Surgery

Introduction

Refractive errors are some of the most common ophthalmic abnormalities world-wide. There have been several conditions like thin corneas, dry eye and prescriptions in higher ranges that have made laser eye treatments off-limits for many people.

But thanks to new technology, it has opened the door to many who would have had sub optimal outcomes with previous lasers; here one can maximize results and minimize adverse effects.

The latest revolution in this field is RELex [Refractive Lenticular Extraction] using the Carl Zeiss VisuMax laser system.

Femtosecond lasers have been in use for some time now, and were started with the intention to replace the microkeratome used for ‘flap’ creation in LASIK. Every pulse in a ‘femtosecond laser’ takes less than one trillionth of a second. A femtosecond is 1-15 of a second or 0.0000000000000001 second.

These ultra short pulses of laser light are used to make very fine and precise incisions in the cornea. Here, the Femtosecond laser is applied first to create the corneal flap, which is then lifted before the application of the excimer laser which treats the refractive power. However, older Femtosecond lasers led to some adverse post operative conditions such as “Transient Light Sensitivity Syndrome” and delayed recovery of vision.

Today, Femtosecond Lasers, such as The VisuMax, go one step further; this new technology has made protecting the cornea’s integrity easier and creating flaps more consistent and precise.

The VisuMax femtosecond laser (Carl Zeiss Meditec AG, Jena, Germany) (Figure) is an attractive choice for two reasons. First, it gives the surgeon an extra margin of safety in creating the flap. Second, it offers a wide range of laser treatments in combination with excimer laser such as FLEx (femtosecond lenticular extraction), or an all – Femtolaser treatment- SMILE (Small Incision Lenticular Extraction) with the additional ability to be used in cataract surgery as well, now being called as FemtoLaser Cataract Surgery and also in keratoplasty. With these wide ranges of treatments available to a surgeon, it is a good investment in Ophthalmologicalpractice.

This new innovation in corneal surgery uses a femtosecond laser alone, compared with other procedures that use an excimer plus a femtosecond laser. With SMILE procedures, because the anterior corneal structure remains largely intact, there is a potential for the safer treatment of higher levels of myopia than is currently possible with excimer laser procedures. The corneal nerves are also mostly spared, so there is theoretically less risk of dry eye problems.

Advantages of this technology

‘Smile’, short for ‘Small Incision Lenticular Extraction’ is no flap, no pain, quick recovery, and fully computer operated by the femtosecond laser.  This new technique, is only possible with the Visumax femotsecond laser by Carl Zeiss, and is the least invasive therapy possible these days.

The disadvantages of the older treatments have disappeared and the advantages have remained. The fact that we now finally do not have to make a flap lowers the chances of dry eyes drastically and improves the stability of the cornea extremely.

Despite its proven efficacy, LASIK still requires the use of two laser machines: one for the flap creation and another for the excimer ablation. This increases the cost as well as the surgical time for the procedure. SMILE uses only one laser machine, thus potentially reduces surgical time and cost. Moreover, SMILE does not involve any flap creation, which potentially reduces risk of side effects such as dry eyes. For these reasons, SMILE is potentially a new, improved form of refractive surgery, which may supersede LASIK and change clinical practice. There is also potentially a positive impact on healthcare as surgical time and costs are reduced with this new, ‘all-in-one’ laser procedure.

Unlike other excimer laser-based procedures, ReLEx smile uses a solid-state laser, and therefore, there is no need for consumable gases or tight environmental humidity control. The VisuMax is a silent, soft, and gentle laser. It does not produce a smell, there is no vision blackout during the procedure, and the cornea is not forced into a non-physiological planar shape. As a result, deformation and artifacts can be avoided in the results as well as unnecessarily high intraocular pressure.

Conclusion

Shroff Eye Hospital, Mumbai is one of the privileged centres in the world which offers the widest range of laser treatments from

• Wavefront LASIK,
• Wavefront Bladeless EpiLASIK,
• Wavefront Trans Epithelial Surface Ablation,
• Topography linked LASIK,
• Bladeless Femto LASIK,
• ReLex- FLex,
• ReLex- SMILE
• ICL (Implantable Lenses).

ReLEx SMILE from the VisuMax Carl Zeiss Laser is a fresh approach to laser eye surgery in myopic patients. Considering that the evolution of refractive surgery is moving towards to the preservation of corneal biomechanics to increase safety and achieve aberration-free results, ReLEx SMILE appears to be a milestone in minimally invasive laser vision correction surgery.