Side-by-Side Comparison Guide

Compare the Stats on Leading LASIK Systems and Ask Yourself: What Does "True" Custom Really Mean?

Some companies can try to convince you that only they have "true" custom LASIK. When it comes right down to it, though, it’s up to you to decide what makes for a truly custom procedure.

Below, you'll find a side-by-side comparison of the leading LASIK systems, including OptiLASIK® Laser Vision Correction, powered by the WaveLight® Allegretto Wave® Eye-Q Laser. Take a close look at the stats, and see what each system can offer you, your patients, and your practice. Once you've seen the facts for yourself, it's not hard to see the truth.

Lasik Comparison Guide

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Source: Seiler T, Koller T. Excimer laser instrumentation. In: Albert D, Miller J, Azar D, Cocks ACF, Blodi B, eds. Albert & Jakobiec’s Principles and Practice of Ophthalmology. 3rd ed. Philadelphia, PA: Saunders W B Co; 2008:981‐985.

The truth is finally out about "true" custom LASIK–and what OptiLASIK® Laser Vision Correction can do to give you more. But don't just take our word for it... Compare specs and come to your own conclusions. The truth just might set you free.

Beam Profile

Generally, most newer-generation LASIK systems do not use top hat beams, which provide uniform beam intensity, instead opting for Gaussian beams, which provide non-uniform intensity based on a Gaussian distribution (ie, the beam is more intense along its central axis). Because of these different energy densities, the Gaussian profile offers improved control of pulse shape, as well as maximum uniformity of each emitted pulse.

The rounded Gaussian beam shape also allows for a finer, more uniform pulse overlap, creating a smoother ablation surface and allowing for more precise custom shaping than top hat beams.1

Source: Thomas JW, Mitra S, Chuang AZ, Yee RW. Electron microscopy of surface smoothness of porcine corneas and acrylic plates with four brands of excimer laser. J Refract Surg. 2003 Nov-Dec;19(6):623‐8.

Gaussian beams provide a smoother ablation area without grooves or ridges in the intersection zones. Top hat beams can result in irregular and rough corneal surfaces, increasing the potential for optical aberrations and scattering.

Beam Size

Custom LASIK requires the ability to precisely correct finer features–particularly when addressing higher-order aberrations. Precise correction, in turn, requires a smaller beam to accurately fine-sculpt the eye. Smaller beam size–also known to as spot size–can provide a variety of benefits, improving predictability and the ability to efficiently correct both lower and higher order aberrations.2,3

The 0.95-mm, ultra-thin profile of the WaveLight® Allegretto Wave® Eye-Q Lasers helps assure consistency and precision in corneal shaping, with a larger optical zone (up to 6.5 mm) and very small transition zones.

Average Fluence

Fluence, also known as radiant exposure, is a measurement of energy over area (in this case, the beam size of the laser). The higher the fluence, the more "cutting power" a laser has. Varying beam size–such as that offered by variable broad beam lasers–causes varying energy levels.

Maintaining fluence is crucial for precise refractive procedures, as the programmed correction assumes consistent energy is applied per pulse.4 Unfortunately, environmental and mechanical factors–dust, humidity, ozone–can actually cause the fluence of many LASIK systems to fluctuate, leading to less predictable results. Luckily, WaveLight® Allegretto Wave® Eye-Q Lasers feature advanced PerfectPulse Technology®, which monitors and helps ensure the energy stability of every pulse, for greater precision and safety, which assist in providing a lower rate of enhancements:

  • PerfectPulse Technology® features a smart, closed-loop energy control program that automatically balances energy levels to help ensure each laser pulse creates the same accurate result.
  • This same technology forms the foundation for OptiLASIK® Laser Vision Correction's unique Wavefront Optimized® LASIK. By compensating for energy loss and potential undercorrection at the periphery of the cornea, PerfectPulse Technology® adds additional pulses to the peripheral cornea, which helps create a more natural, aspheric shape, with less induced spherical aberration.5

WaveLight® Allegretto Wave® Eye-Q Lasers feature PerfectPulse Technology®, for more consistent energy control.

WaveLight® Allegretto Wave® Eye-Q Lasers feature 3-sensor energy control. They also check the energy at the point when the beam leaves the laser system. This is important since the energy at the cornea is what matters.

Pulse Frequency

Pulse frequency is the "firing rate" of the laser. Faster repetition rates allow for faster treatments and minimal exposure to external environmental influences, for optimal patient outcomes and potentially faster visual rehabilitation.6

The WaveLight® Allegretto Wave® Eye-Q Laser offers a high-speed pulse frequency of 400 Hz, enabling you to achieve a correction time of 2 seconds per diopter. This rapid, efficient treatment offers many advantages to your practice and your patients, including:

  • Increased patient comfort
  • Low potential for complications
    • Decreased exposure to the effects of temperature and humidity
    • Reduced risk of decentration
  • Excellent clinical results
  • Optimal patient flow, faster throughput, less stromal hydration and flap drying

High pulse frequency can be associated with elevated corneal temperature when cumulative ablation energy is confined to a small area.2

  • Fortunately, WaveLight® Allegretto Wave® Eye-Q Lasers help prevent thermal effects with optimized shot distribution, only allowing every fifth pulse to overlap with a previous one, so that the affected area has sufficient time to cool in-between pulse application.
  • Minimalizing thermal effects may play a role in speeding up the healing process.2

Eye Tracker Sampling Rate

Beam size, pulse frequency, energy control–all of these aspects are important when choosing a laser. But the best laser isn't worth a thing unless it's backed by an eye tracker that ensures that each pulse is placed exactly where it was intended.7

During treatment, random saccadic eye movements can occur up to 5 times a second, traversing a distance of 0.1-2 mm at a rate of 22-170 mm/sec.7 To compensate for this near-constant pupil shift, eye tracking technology needs to offer rapid latency response time, with extremely accurate eye alignment.

WaveLight® Allegretto Wave® Eye-Q Lasers use an advanced, high-speed tracking system that follows even the fastest eye movement. Natural eye movements range from 20-60 Hz; the WaveLight® Allegretto Wave® Eye-Q Laser can track pupil shifts at 400 Hz, with a response time of less than 6 ms.

Featuring a synchronous, video-based, closed-loop tracking system, WaveLight® Allegretto Wave® Eye-Q Lasers help reduce treatment errors caused by eye movement:

  • Active video tracking continually verifies eye position and automatically corrects shot placement based on natural eye movement. With rapid image sampling rates and closed-loop feedback of eye position, the tracker maintains a space-stabilized image with minimal latency, which helps to ensure that every pulse goes to the desired location.7
  • To maintain high-speed correction, PerfectPulse Technology® multitasks the tracking process. Even as the eye tracker adjusts the mirrors for a pulse, it is already beginning to determine the eye position for the next pulse.

References

  1. Thomas JW, Mitra S, Chuang AZ, Yee RW. Electron microscopy of surface smoothness of porcine corneas and acrylic plates with four brands of excimer laser. J Refract Surg. 2003 Nov-Dec;19(6):623-8.
  2. Mrochen M, Schelling U, Wuellner C, et al. Influence of spatial and temporal spot distribution on the ocular surface quality and maximum ablation depth after photoablation with 1050 Hz excimer laser system. J Cataract Refract Surg. 2009;35:363-373.
  3. Huang D, Arif M. Spot size and quality of scanning laser correction of higher order wavefront aberrations. J Cataract Refract Surg. 2002;28:407-416.
  4. Seiler T, Koller T. Excimer laser instrumentation. In: Albert D, Miller J, Azar D, Cocks ACF, Blodi B, eds. Albert & Jakobiec's Principles and Practice of Ophthalmology. 3rd ed. Philadelphia, PA: Saunders W B Co; 2008:981-985.
  5. Waring GO, Durrie DS. Emerging trends for procedure selection in contemporary refractive surgery: consecutive review of 200 cases from a single center. J Refract Surg. 2008;24:S419-S423.
  6. Alio JL, Hamid IM. Intraoperative complications of LASIK. In: Albert D, Miller J, Azar D, Cocks ACF, Blodi B, eds. Albert & Jakobiec's Principles and Practice of Ophthalmology. 3rd ed. Philadelphia, PA: Saunders W B Co; 2008:1051-1059.
  7. Chalita MR, Krueger RR. Wavefront-guided excimer laser surgery. In: Albert D, Miller J, Azar D, Cocks ACF, Blodi B, eds. Albert & Jakobiec's Principles and Practice of Ophthalmology. 3rd ed. Philadelphia, PA: Saunders W B Co; 2008:1041-1049.

All claims based on clinical study data analysis completed in May 2008 and presented in the CE Technical file. Refer to the Physician’s Directions for Use for more information.