Equipment

Refractive Centre Prague is proud to introduce to you the unique Bausch&Lomb Zyoptix® system.
This comprehensive system designed for performing diagnoses and following elimination of dioptre defects by excimer laser, can be offered to you as the only system in the Czech Republic.

Original software improves the offer of treatment possibilities:

DIAGNOSTIC – diagnostic workstation ZDW
TREATMENT PLANNING – calculation of laser surgery algoritmh Zylink Software
THERAPY – XP Microkeratome, Zyoptix Laser Technolas Z 100

ZYOPTIX® DIAGNOSTIC WORKSTATION

The Refractive Centre Prague uses a completely unique Zyoptix system which consists of the Zywave II. aberrometr and the Orbscan II Z corneal topograph manufactured by Bausch & Lomb.

 Orbscan® II Z corneal topograph

This equipment is used to examine the cornea and the eye’s anterior segment. It enables us to perform a very thorough, 3D analysis of the anterior corneal surface and of the posterior corneal surface (which is unique), to determine the exact thickness of the cornea in its entire range, measure the depth of the eye anterior chamber and the width of a pupil. Curvature parameters, corneal thickness, and the width of the pupil are very important to detect the conditions where the laser procedure would be contraindicated (very thin cornea, anterior or posterior keratoconus, etc.). The instrument is also able to do 3D simulations of the eye’s anterior segment, and determine other parameters needed for the accurate evaluation of preoperative and postoperative findings.

Zywave® II Aberometr

"Wavefront" technology is the latest trend in laser refractive surgery. It is an individualized measurement of the eye’s optical properties to determine not only the patient’s underlying dioptric defect, but also higher-order aberrations. Higher-order aberrations are often responsible for the impaired quality of a patient’s vision and cannot be compensated using common optical aids. Wavefront technology is based on complicated mathematical analyses that are also used in astronautics and astronomy.
In laser surgery, they help to make a complete and exact picture of the qualitative and quantitative condition of the eye’s optical apparatus, assess the quality of vision in the dark, and quantify the occurrence of visual side phenomena.

TREATMENT PLANNING – Zylink® SOFTWARE

Original software improves the offer of treatment possibilities :

• Zyoptix® Personalized
• Zyoptix® Aspheric 
  Zyoptix® Tissue Saving

The basic attributes of the excimer laser refractive procedure are as follows: Safety, economy, individuality, predictability, and, naturally, efficiency. This is covered by the Zyoptix® system in the modes stated above. The Zyopix®Tissue Saving procedure significantly reduces the amount of tissue removed during the procedure. Based on wavefront analysis, the Zyoptix®Personalized accepts the individual needs of each patient.
The presumable peak is perhaps the Zyoptix® Aspheric. In myopia treatment using the conventional methods of excimer laser therapy, flattening of the originally rounded anterior corneal area can occur (in earlier equipment, even the convex curvature happened to be changed to concave – from a concave anterior area to convex).
We are talking about the phenomenon of the occurrence of post-operative spherical aberration, which means that the light beams passing through the newly shaped corneal surface are refracted into more foci instead of striking a single focus. This beam diffusion causes contrast sensitivity reduction, night vision problems ( glare and halos) and especially subjectively unsatisfactory vision.

The advanced surgical procedure aims to reduce induced spherical aberration and induction of corneal asphericity. Its measurable value is the Q factor, indicating the degree of variation from a perfect corneal sphere. The Q factor of a normal human cornea has a negative value. A negative Q factor indicates that the corneal curvature is flattened from the centre into the periphery and a positive Q factor indicates corneal rounding from the centre into the periphery.
Thanks to the unique Zyoptix® Aspheric programme, patients can be guaranteed up to 77% reduction of spherical post-operative aberration and total reduction of high order aberrations. This basically provides also objective and subjective enhancement of vision functions even in reduced light conditions.

XP MICROKERATOME

  X-TRA PRECIZION

• There is no safer or more precise and fast method of a regular corneal flap creation available today
• PREDICTABLE

 Enhanced safety is achieved through:

• A suction ring design that reduces the potential for pseudosuction, slippage and suction break
• Optimizing the rate of movement 
• A gearless drive assembly providing safe microkeratome head movement without the risk of continuous movement break
• The microkeratome head labelling clearly reflects the flap thickness

PRACTICAL

• LASIK with XP Microkeratome is significantly faster (3 to 4 minutes) than the latest generation of femtosecond lasers (FL)
•  The XP component assembly has been simplified as much as possible, making the equipment easy to operate and use
• A right eye/left eye selector switch facilitates the transition between the eyes during the procedure
• A larger diameter bed under the lamella allows photo ablation in wider optical treatment areas
• 360° variable hinge positioning
• All parts being handled during the procedure can be sterilized

XP Microkeratome versus Femto Laser (FL)

The mechanical XP Microkeratome delivers several significant advantages over the FL in corneal flap creation:

It is a one-laser procedure

• Faster flap creation with the XP as compared to the FL
• Shortening the procedure means less drying of the eye, which can affect the accuracy of the laser procedure (stromal drying)
•  With a mechanical Microkeratome XP suction is engaged for 10-15 seconds only, rather than the 1 minute or more required by the FL for flap creation (less time further reduces the risk of potential retinal or optic nerve trauma, caused by intraocular pressure changes)
• The XP Microkeratome creates sharp edges of the flaps so there is no need to perform manual dissection of the flap compared to the FL
• For the same reason the risk of an unintended flap movement in the early post-operative stage is reduced
• Foreover, the FL surgery safety has not been yet solved regarding the corneal endothelium, especially in thicker flap creation

Zyoptix® TECHNOLAS Z 100 EXCIMER LASER

The quality of the equipment has been proved by the fact that it is the most widespread laser equipment world-wide. The next great asset is that not only the laser itself, the first-rate microkeratome, but also the necessary diagnostic devices and software are tailor-made by the same manufacturer. Science and research have intermingled, creating a perfect symbiosis.
Some components used in the Zyoptix® system cannot be compared to the competitors. First of all, the following should be highlighted:

• Iris Recognition System
• Multidimensional eyetracker

Iris Recognition a Multidimensional eyetracker

The iris is the pigmented inner, visually dominant, eye structure surrounding an aperture called a pupil designed to control the amount of light entering the eye. Each iris is uniquely structured depending on its tissue structure formed from muscle fibres, colour and ligaments. Pigment spots, radial and concentric furrows, cavities, etc. can be recognized here.
The layout of the above indicators on each iris provides a unique pattern that can be used for human identification similar to the uniqueness of every fingerprint or retinal scan.
Iris Recognition allows focusing the equipment precisely on the stated individual iris indicators. The system is the only one so far in use that is thus able to eliminate errors during torsional eye movement caused by the patient’s change of position during diagnostic examinations and the laser procedure itself. Two independent special infrared cameras continually compare reference points on the iris obtained in the diagnostic unit examination with the points scanned in the relevant laser procedure, calculating position changes including the torsional angle of movement. At the same time, the system operation is absolutely independent of the width of the pupil scanned.

During surgery, the patient’s eye movement is naturally unavoidable. In addition to movements within the commonly used system of x, y, and z axes (i.e. left-right, up-down and forward-back), torsion (rotation) also plays an essential role. Moreover, it has been documented that it is the intervention decentralisation during eye rotation which is the most dangerous for the final effect on post-operative vision. Only a few devices used in laser treatment are able to register the rotation variation. This can be achieved by a combination of the Iris Recognition system and multidimensional eyetracker of the Zyoptix® system. During the laser surgery process, beams are deflected as necessary so that their incidence on the cornea is according to the pre-calculated schedule. If the tolerated limits are exceeded by the movements, the procedure is automatically stopped and continues after the eye movement has ceased. The risk of distorted vision is thereby avoided.

Synergy of the Excimer Laser and Eyetracker