Modern Excimer Lasers Used for LASIK

All approved excimer lasers meet safety and effectiveness criteria established by the FDA. The main differences among LASIK lasers are the patterns they use to deliver the laser beam and track the eye during laser eye treatment. Types of Excimer Lasers:Spot scanning lasers.

Slit scanning lasers.

Wavefront-guided lasers.

How Do Excimer Lasers Work?

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Spot scanning lasers:

Spot scanning (or "flying-spot") lasers, which are the most common, use small-diameter laser beams (0.8 to 2 mm) scanned across the corneato produce the treatment zone.

This approach has the potential to produce the smoothest corneal treatments, to more readily allow customized treatments and to better treat irregular astigmatism.

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Slit scanning lasers:

Slit scanning lasers use relatively small beams linked to a rotational device with slit holes that enlarge.

The laser beams scan across these holes during surgery, producing a gradually enlarging ablation zone.

This approach produces a uniform beam that creates smoother treatments than older broad-beam lasers.

But slit scanning lasers have the potential to cause a slightly greater risk of decentration and over-correction unless an eye tracker is used, or with an inexperienced surgeon.

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Wavefront-guided lasers

Many excimer lasers, whether spot or slit scanning, are connected to a device that detects and "maps" defects in the eye's optical system, based on how light travels through the eye.

These wavefront devices produce a custom LASIK treatment that is unique to each patient. Both slit scanning and spot scanning lasers can be used for wavefront-guided treatments

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How Do Excimer Lasers Work?The excimer laser emits a cool beam of ultraviolet light of a specific wavelength (typically 193 nanometers) to precisely remove corneal tissue.

When the surface of the cornea is reshaped in the right way, it allows light rays to focus properly onto the retina for clear vision.

The high-energy pulses of ultraviolet light penetrate only a tiny amount of the cornea and have the ability to remove as little as 0.25 microns of tissue at a time.

An excimer laser corrects nearsightedness by flattening the cornea; it corrects farsightedness by making the cornea steeper. Also, astigmatism can be corrected by smoothing an irregular cornea into a more normal shape.

Maintained by Visual Aids Centre Owner: Vipin Buckshey