LASIK & LASEK Technology

Laser Vision Correction (LASIK & LASEK)

The Excimer Laser: VISX StarS4 ActiveTrak™

© VISX, Incorporated At Grange Eye Consultants your laser correction will be performed at either the Nuffield Hospital in Chandlers Ford or in Taunton. The excimer laser used is the new VISX Star4 laser, the very latest version of the world's most widely used and studied excimer laser. The VISX laser is appreciated by both patients and surgeons alike for its unique 3-dimensional eyetracker, and outstanding record of safety and accuracy.

The exclusive ActiveTrak™ is the only system that allows the doctor to track eye movement in all three dimensions. Having the beam centered correctly on the eye at all times helps ensure precise results. Unlike other lasers with eye-tracking technology, ActiveTrak™ requires no pupil dilation, leading to a quicker and more comfortable procedure. This is an important feature to assist both patient comfort and surgeon confidence.

This VISX laser system produces an extremely smooth surface on the cornea after the procedure. Smoother ablations, as they're known, promote faster healing and result in better visual outcomes. In addition, the new S4 laser achieves an optical zone up to 8mm in order to avoid problems with night vision. With a shorter procedure time than many lasers, all this enhances comfort and may reduce the risk of postoperative complications.

This is the same brand of laser that was trusted by Richard Branson and Tiger Woods on their own eyes, and now this technology is available in Hampshire.

Microkeratome
We use the Bausch & Lomb Hansatome™ microkeratome. This high precision instrument is used for the first stage of the operation, to create the flap under which the laser operates during the LASIK procedure. We always use a new blade for each eye.

A detailed corneal topography map

Corneal Topograpy
Corneal topography is a computer assisted diagnostic tool that creates a three-dimensional map of the surface curvature of the cornea. The cornea (outer surface of the eye) is responsible for about 70% of the eye's focusing power. An eye with normal vision has an evenly rounded cornea, but if the cornea is too flat, too steep, or unevenly curved it is said to have astigmatism and this affects clear vision. The greatest advantage of corneal topography is its ability to detect irregular conditions invisible to most conventional testing.

The corneal topography equipment consists of a computer linked to a lighted bowl that contains a pattern of rings. During a diagnostic test, the patient sits in front of the bowl with his or her head pressed against a bar while a series of data points are generated. The computer software then digitizes these data points to produce a printout, or map, of the corneal shape. Different colours are used to identify different elevations just as a topographic map of the earth displays changes in the land surface. There is no contact with the eye so the test is quick and painless.

These results, combined with a series of other tests help the surgeon determine how much corneal tissue will need to be removed from where to achieve the desired visual outcome. This data is then programmed into the excimer laser ready for your treatment.

NEW Wavefront technology

No two eyes are the same. Like your DNA or fingerprint, your vision is unique.

Although millions of patients have now been treated successfully with LASIK, wavefront refractive technology breaks new ground in terms of safety and accuracy for future LASIK patients. At Grange Eye Consultants we are pleased to be able to offer you the benefits of the WavePrint™ map. This is a unique fingerprint of your vision that displays all the refractive errors and aberrations of the eye. Using the WavePrint™ Map, the surgeon can more accurately assess whether you are a good candidate for laser vision correction.

Acuity Map

How Wavefront technology works
Light travels in a procession of flat sheets known as wavefronts. These wavefronts enter the eye, pass through the entire optical system, including the cornea and lens and are then reflected back off the retina. If the optical system has no refractive errors at all (ie. perfect refracting surfaces) which is rare, these wavefronts would exit the eye as regular, flat sheets. But if the cornea or lens has any imperfections higher-order aberrations (distortions) are created, and the wavefronts exit the eye as irregular, curved sheets.

Wavefront technology compares these curved sheets to a perfect wavefront. The system then determines what adjustments are needed in order to produce a clearly focused image on the retina.

Until now, conventional laser vision correction could only correct the lower order aberrations (or visual distortions). These are also corrected by glasses or contacts and include short-sightedness (myopia), long-sightedness (hyperopia) and astigmatism. It is estimated that these lower order aberrations account for 85-90% of the overall quality of your vision. The remaining 10-15% is affected by higher-order aberrations. You may have 6/6 (20/20) vision, but due to higher-order aberrations this may not be as ‘crisp’ as it could be. With wavefront, we now have technology that can potentially achieve better than 6/6 (20/20) vision.

Normal Wavefronts

Wavefronts with aberrations

Corneal Topography has been used for years to provide information on the corneal surface, but wavefront technology goes one step further to map not just the corneal surface but all aspects of the eye that process light.

The new WavePrint™ System by VISX takes laser vision correction to an entirely new, personalised level by combining exclusive individual diagnostic technology and the Excimer laser into one system.

The advanced diagnostic portion of the technology produces a precise, detailed analysis of the entire optical path of your eye and provides a personalised laser vision correction plan that addresses your individual needs. This WavePrint™ map is coordinated with the VISX STAR S4 ActiveTrak™ Excimer Laser System to create one of the most advanced systems on the market.

The standard LASIK procedure is capable of correcting refractive errors (myopia, hyperopia and astigmatism) and routinely achieves 6/6 results. As the WavePrintTM system is more precise than any other optical measurement, using this with LASIK does more than correct just refractive errors, it can lead to better vision than you had pre-op with your glasses or contact lenses.
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