Louis Probst, MD
LASIK Surgeon

Ultra-fast laser vision correction

The WaveLight® EX500’s speed of approximately 1.4 seconds per diopter is achieved in part through 1050 Hz-type eye tracker, which is synchronized to the laser frequency at 500 Hz, with a 2 ms latency time.

The results of these faster procedures can include:

• Highly precise treatments
• Less dehydration of the cornea
• Fewer influences through patient movements

Safety Measures

An ultra-thin Gaussian laser beam at 0.68 mm (FWHM) spot size is used to sculpt the corneal surface with the utmost precision. In order to further enhance the safety and precision of the treatment, PerfectPulse Technology® uses proprietary eye-tracking technology to follow the eye’s fastest movements and to ensure an accurate placement of each laser pulse on the cornea.

Precision pulse placement

Finding the eye’s correct treatment position and avoiding displacements is one of the most important factors in obtaining an excellent refractive outcome. Evolved eye-tracking technology used by the WaveLight® EX500 Excimer Laser is designed to ensure quality pulse placement.

Features include:

• Z-axis alignment
• Cross-line projector
• WaveLight® advanced lighting system
• Multi-spatial eye tracking

WaveLight® advanced lighting system

The WaveLight® advanced lighting system, used in conjunction with the 1050 Hz eye-tracking system, helps minimize patient eye movement during the procedure.

Multi-spatial eye tracking

The WaveLight® EX500 Excimer Laser features a multi-spatial 1050 Hz-type eye tracker (synchronized at 500 Hz) with a latency time as little as 2 milliseconds.

Tracking at speeds 10 times faster than movements of the natural eye, the tracker provides exact positioning of the calculated ablation profile to optimize treatment results.

To monitor the patient‘s eye, the active eye tracker utilizes three infrared light sources with minimal risk of distortion by the operation field illumination.

Multitask eye-tracking process

At the same time that the eye tracker loop adjusts the mirrors for the first pulse, it’s already starting to determine the position of the eye for the second one. This multitask functionality enables precise eye tracking even at high speeds.

Closed loop eye tracking

Active, video-based, closed loop tracking scheme: The system captures the image, processes it and verifies the position of the eye with the next image before releasing the pulse.

Cross-line projector

Enhancing precision, the integrated cross-line projector provides the surgeon with an exact alignment of the head and eye, indicating an appropriate patient position.

Practicality and ease of use

The WaveLight® EX500 Excimer Laser and bed are designed to support practicality and ease-of-use.

• Comfortable working environment: A working distance of 25 cm provides a user-friendly experience for the physician.
• Optimized illumination: An automated, multifunctional illumination system provides excellent visibility of the treatment area.
• High-definition optics: The microscope view is not distorted by the laser optics. It provides a direct view of the patient’s eye, resulting in excellent visibility of the operation field area.
• Non-Contact Online Pachymetry: A built-in OLCR-based interferometer measures and illustrates static (pre-op/post-op) and dynamic (during surgery) corneal thickness while minimizing dehydration.
• WaveLight® LED Slit Illumination System: Illuminates the anterior segment of the eye during preoperative microscope evaluation and postoperative examination. It assists in ensuring a properly re-aligned flap that is free from potential debris immediately following the procedure.
• Swiveling Patient Bed: A fast swivel speed with adjustable height optimizes the patient flow between femtosecond and excimer laser devices to provide precise and easy patient positioning.

Adaptable to your practice

Additionally, the easy-to-clean user interface includes a keyboard, control panel and high-resolution monitor to boost surgeon and staff visibility. The ready-access control pad provides immediate laser control to the surgeon throughout the procedure.

Another benefit is that, in most cases, costly architectural changes to the operating room aren’t necessary, due to the laser’s sealed beam path. The system’s reduced space requirements means it can fit in a wide range of surgical suites. And in order to maintain high hygienic standards, all parts of the laser system that might be touched during surgery can be fitted with sterile covers.

Wavefront Optimized® custom ablation profiles

WaveLight® technology is a pioneer in wavefront research. In fact, the world’s very first wavefront-guided procedure was performed on a WaveLight® excimer laser.

WaveLight® excimer lasers are the only systems to use Wavefront Optimized® ablation profiles as part of every treatment. This helps to prevent or reduce the induction of spherical aberrations and may result in better night vision and less sensitivity to glare.

The principle of Wavefront Optimized® ablation is that the natural shape of the human cornea is aspheric, and thus all light rays meet in one sharp focus point.

WaveLight® excimer laser systems perform an ablation with the objective of maintaining a natural corneal shape, preserving the cornea’s asphericity. Every treatment is customized to the patient’s individual refraction and corneal curvature by taking K readings into consideration.

Fluence of laser beam

Due to the angle of incidence, the light of the laser beam is increasingly ovalized toward the periphery and becomes less fluent, which results in less energy.

Ablation profile comparison

Wavefront Optimized® ablation laser systems place more pulses in the peripheral area to compensate for energy loss and reflections. This is designed to provide a nearly 100% optical zone and a minimized transition zone. It is also designed to preserve the natural aspheric shape of the cornea and minimize the induction of spherical aberrations.

In treatments that do not use Wavefront Optimized® ablation profiles, the decreased fluence and reflections are not compensated and the ablation depth in the peripheral area is insufficient.1 As a result, the transition between the optical zone and the transition zone is less smooth, while the transition zone itself is fairly large. The non-aspheric ablation profile alters the natural corneal shape and induces spherical aberrations.

Understanding spherical aberrations

Spherical aberrations are created by ingoing light rays at the periphery. Wavefront Optimized® treatment profiles keep the natural asphericity of the cornea; therefore, all ingoing light rays meet at one point. Non-aspheric ablations change the corneal asphericity, causing the light rays from the periphery to be focused at different points, which leads to a compromise in image quality and night vision disturbances.

Smart energy control
Pulse Optimization

The WaveLight® EX500 Excimer Laser system’s Gaussian beam7 profile is optimized for ablations on the cornea and helps to provide a smooth ablation without grooves or ridges. The tiny 0.68 mm (FWHM) spot size is consistent throughout the complete treatment, thereby providing a precise ablation of corneal tissue and very small transition zones.

In addition, the Gaussian beam profile provides improved control of the pulses’ shape with maximum uniformity of each emitted pulse.

WaveLight® excimer laser systems are the only ones in the market to adjust the beam profile and energy distribution with a special optical electronic beam analyzing system during preventive maintenance. This results in an optimal Gaussian beam profile, optimized pulse overlapping and smooth surface qualities.

The advanced beam path technology of the WaveLight® EX500 Excimer Laser provides high performance and long optics’ lifetime, keeping service costs to a minimum. The beam path is completely sealed and continuously flushed with nitrogen. This avoids contamination while maximizing energy stability and providing constant beam quality. The result is minimal energy dispersion and enhanced optics longevity.

Featuring a very short, closed loop beam path, the WaveLight® EX500 Excimer Laser maximizes laser head energy, is less influenced by environmental conditions and delivers stabile energy and excellent treatment results. The beam path is cleaned by ultrasound before it is built into the laser system to enhance the lifetime of the laser head.

Comparison of Closed Loop Energy Control

Smart calibration control
Predictable results

To promote reliability and predictability, the WaveLight® EX500 Excimer Laser features an objective and precise high-resolution fluence calibration routine. The system is exactly aligned through a maximum calibration tolerance in as little as 2%. Performing the calibration routine before each procedure leads to improved and reliable treatment results.

The intuitive calibration routine consists of:

• A user-friendly, automated energy calibration with a high-resolution measurement device
• An automated eye tracker test (video-based and operator independent)
• An ablation depth micrometer, which is used once every surgery day on a PMMA target, ensuring energy calibration within a tolerance of less than +/- 1.5 μm.

The calibration routine results in:

• Easy and precise laser setup
• Precise and objective calibration
• Precise laser alignment
• User-independent quality control and documentation
• Accuracy of +/- 0.2 D for a -10.0 D treatment

Three-fold accuracy

The simple and user-friendly calibration routine ensures predictable and consistent stability of laser energy.

1. Once a day - Ablation depth micrometer helps provide precise energy calibration with a PMMA target
2. In-between treatments - Electronic energy control with a highly sensitive energy meter
3. During treatment - Ongoing energy control through closed loop energy sensors