Advanced LASIK

CUSTOM LASIK

Custom treatments fall into 2 categories: Wavefront Guided (WFG) and Wavefront Optimized (WFO). A wavefront is a map of the optical irregularities of an individual eye. Much like a fingerprint, a wavefront is unique for each eye measured. This map quantifies both lower (LOAs) and higher order aberrations (HOAs). LOAs include the amount of near or farsightedness and the amount of regular astigmatism. These are the aberrations that are correctable with glasses or contact lenses. HOAs include more irregular imperfections that cannot be corrected with glasses or contact lenses. The most important HOA is spherical aberration which is responsible for night-time glare and halos as well as difficulties distinguishing shades of grey at night (poor contrast sensitivity). Most people have very few HOAs with the exception of spherical aberration. As a result, the reason that most patients benefit from WFG treatments is because of this technique’s ability to treat spherical aberration. WFO treatments also reduce spherical aberration but are able to do so without removing as much corneal tissue as WFG treatments. Consequently, the vast majority of patients who are candidates for LASIK or PRK are best served with a WFO treatment.

How Wavefront Technology Works

Wavefront acquisition After a light is reflected off the retina, the wavefront analyzer captures the light exiting the eye, recording it in detail. The wavefront device transmits a ray of light or an array of multiple lights into the patient’s eye. The light is reflected off the retina and is captured by the wavefront analyzer as it exits the eye. Each eye’s visual irregularities are recorded and displayed as a three-dimensional, wavefront map. At the UCLA Laser Refractive Center, we measure the wavefront on each eye during the pre-operative evaluation. Your surgeon will determine which custom treatment, WFG or WFO, would offer you the best outcome.

The emmetropic (“normal”) eye Light exits the eye in parallel rays, represented by a flat wavefront.	Perfect Eye Chart Eye chart as seen by an emmetropic eye.

LOWER ORDER ABERRATIONS
The myopic (“nearsighted”) eye Light exits the eye in converging rays, represented by a dome-shaped wavefront.	Nearsighted Chart Eye chart as seen by a myopic eye.
The hyperopic (“farsighted”) eye Light exits the eye in diverging rays, represented by a dome-shaped wavefront.	Farsighted Chart Eye chart as seen by a very farsighted eye.
The astigmatic (“football-shaped”) eye Light exits the eye in rays represented by a saddle-shaped wavefront.	Astigmatism Chart Eye chart as seen by an astigmatic eye; distortion is in the direction of the astigmatism.

HIGHER ORDER ABERRATIONS
An eye with spherical aberration Wavefront of an eye with spherical aberration. This is the most common aberration responsible for poor quality of vision, particularly at night. This aberration is treated with Wavefront Optimized treatments.	Spherical Aberration Chart Eye chart as seen by an eye with spherical aberration; note halo distortion, often seen around lights at night.
An eye with high coma (i.e., keratoconus) Wavefront of an eye with coma; abnormal corneal shape such as seen in keratoconus.	Coma Chart Eye chart as seen by an eye with high coma; note comet-shaped, tail-like distortion.

BLADE FREE LASIK

Traditional LASIK eye surgery involves a device called a mechanical microkeratome to create the LASIK flap. This is a high precision blade system that creates a very thin flap in the front of the cornea. LASIK with a microkeratome remains an excellent option for LASIK eye surgery. There is now a Blade-FREE LASIK option which uses a femtosecond (FS) laser. This technology enables the surgeon to be more precise with the size and thickness of the flap. In addition, the rare flap complications that could occur with a microkeratome have been nearly eliminated. Both the United States Air Force and NASA have accepted Blade-FREE LASIK as a standard for their professionals who have LASIK vision correction.

The FS laser uses ultra fast pulses of laser light to position thousands of microscopic bubbles at a precise depth in the cornea, as specified by your surgeon, creating a plane. Next, the laser stacks bubbles around the periphery of this plane to create the edges of your flap. These bubbles are stacked at an angle that is determined by your surgeon and is customized to the way your eye is shaped. The process takes only about 30 seconds from start to finish—it’s quiet and it’s comfortable. You will only experience some pressure on the eye during this period. (Remember, there are no blades so you will never feel anything sharp on the eye.) Your surgeon will then gently lift the flap to allow for the second step of your LASIK treatment: the reshaping of the cornea. When treatment is complete, the surgeon repositions the flap and it begins to heal immediately.

The accuracy and predictability of the femtosecond laser has allowed some patients who were previously ineligible for LASIK, to now have the procedure. With the FS laser, unlike with mechanical instruments, your surgeon is able to precisely program the dimensions of your flap (diameter and thickness) based on what’s best for your eye. Dr. Hamilton and his colleagues published a scientific study that suggests the use of a femtosecond laser to create the LASIK flap produces a more consistent and predictable effect on corneal biomechanics (i.e. strength of the cornea) than the use of a microkeratome (blade) system*.

If you are seeking a Blade-FREE LASIK practice in Los Angeles, call us to learn more about this LASIK technology that has helped so many patients to date. At your consultation visit, your UCLA Laser Refractive Center surgeon will discuss whether Blade-FREE LASIK or an alternative refractive procedure best matches your eye condition and visual needs.

* Hamilton DR, Johnson RD, Lee N, Bourla N. J Cataract Refract Surg. 2008 Dec; 34 (12):2049-56.

MONOVISION LASIK

Patients in their mid to late 40s and beyond suffer from presbyopia, the natural loss of focusing power (i.e. accommodation) of the eye’s crystalline lens. This manifests itself through the need for reading glasses or progressive/bifocal spectacles.

Monovision is a technique that makes use of the fact we have 2 eyes. It can be created using either LASIK or PRK.In this technique, one eye is set for distance vision while the other is set for near vision. After an adjustment period which usually lasts several weeks, the brain adapts to this new optical arrangement. Soon after the adaptation, the patient can see far and near seamlessly. Monovision works for a wide range of visual needs and when using both eyes together, it will typically provide adequate distance and near vision for most tasks. It may not be the best choice for all patients. Ask your UCLA Laser Refractive Center surgeon if monovision is right for you.