Dr Samir Melki MD - Leading Boston Lasik Surgeon

The Technology Behind LASIK Surgery

the-technology-behind-lasik-surgery

Over the past few decades, the world has witnessed a lot of unprecedented development in technology and the field of medicine is no exception. The use of laser has now been incorporated with medical operations including eye surgeries.

Corrective eye surgery which aims to fix impaired vision due to nearsightedness, farsightedness and even astigmatism, has employed laser technology to provide lasting result without needing eyeglasses or contact lenses. This surgical procedure, which works by reshaping the eyes’ natural lens, is called LASIK Surgery. LASIK stands for Laser-Assisted in situ Keratomileusis.

Further developments makes the surgery more precise, more effective and much safer compared to previous practices. As a result, various LASIK-related technologies have been made available and one may choose which technology to use.

LASIK Procedure

The surgery aims to reshape the Cornea of the eye to achieve its ideal focus. Patients with myopia or nearsightedness needs to have a flatter cornea while those who have hyperopia or are farsighted need a steeper shape. Meanwhile, patients suffering from totally blurred vision will need to alter the irregular shaped cornea to become much smoother.

Only the cornea needs to be shaped but since it is covered with a thin layer of transparent epithelial cells, the covering will have to be removed first. So the first thing to be done is to create a flap from the Epithelium about the size of the cornea, then fold it away from the field of the laser.

Keeping the flap and replacing it afterward has been observed to promote faster healing. This is because the epithelium provides protection and nutrition to the cornea. There are two ways to create the flap. The first is through a small mechanical blade and the second one is through the use of laser.

Bladed And Bladeless LASIK

Earlier versions of LASIK use an instrument called microkeratome to create the flap. In this procedure, a small mechanical blade is used by the surgeon. In the late 1990’s, however, femtosecond laser have been introduced as means in creating the flap instead of using a blade. Thus, making the procedure an all-laser surgery. At present, some modern surgical machines still use improved versions of microkeratome for added efficiency.

For patients undergoing LASIK surgery, both procedures do not have any direct impact on the result. As long as the procedure successfully went well, there is no difference in the way it affects the eye. Surgeons however notice that using microkeratome results in a flap that is thinner on the center as compared to flaps created by laser. Furthermore, Femtosecond laser appears to take more time, ranging from fifteen to twenty second compared to mechanical blade which could only take 3 seconds.

Excimer Lasers

To reshape the cornea, surgeons use excimer lasers. The laser is produced by applying electric stimulation and pressure to molecules which are usually of noble gas. The laser causes thin layers of the tissues of the cornea to evaporate. The areas where laser is applied depends on each patient’s condition and is determined through preoperative consultation and examination. As such, it is unique for every patient.

There are different types of lasers used in LASIK surgical procedure. Depending on the equipment used and on the manner how the laser is applied. Modern types are far more complex and are aimed to fix visual conditions that may be too complicated than what traditional LASIK could handle.

Spot Scanning Laser

The most common type of laser used in eye surgery is spot scanning lasers. It uses laser beams with small diameter scanned across treatment zone of the cornea. This approach has been observed to create a smoother and more even surface.

Slit Scanning Laser

The second laser type is the slit scanning lasers. Instead of using a circular beam, the device has slit holes that enlarge. The laser beam passes through the slits while the device rotates. This technique results in a more uniform distribution of beam than the spot scanning laser.

However, slit scanning lasers have higher risk of decentration which may cause glare, double vision and halos. This happens when the laser is not centered on the pupil upon ablation. This type has also been associated to higher risk of over-correction.

To address this issue, modern LASIK equipments use eye tracking system that follows the position of the eye. This lets the laser refocus on the correct area of the cornea in case the eye moves to ensure that the cornea is correctly reshaped as desired. Modern tracking system can follow the eye with the speed of four thousand times per second.

Wavefront-Guided Laser

The newest type of laser is wavefront-guided laser. This type tracks or maps the irregularities on the eye to apply varied or custom treatment. This is done with the help of wavefront sensor that is attached to the LASIK device. This benefits patients with irregular eye disorders with which traditional LASIK methods may not sufficiently fix.

Wavefront-guided laser machine uses either spot scanning lasers or slit scanning lasers during ablation process.

Choose The Right One

Some types or technology involved in LASIK are nothing but enhancement to get better, faster and hassle-free results which means they should not matter much to patients. However, some patients might need to get the more advanced option to get their conditions properly addressed. To better decide which type one needs, one may contact an ophthalmologist for examination.

The eye condition is critical in deciding which type to use. If given the option to select, it is important to remember that the more advanced the procedure is, the more expensive it can get. While many clinics offer the service at a fixed rate no matter what technology is used, others let you choose and quote the price based on your selection.

Generally, microketome surgery is much cheaper than all other laser surgeries. On the other hand, wavefront-guided lasers are typically the most expensive.

These technological advancements in the field of laser eye surgery are definitely welcomed by both patients and surgeons. One day, medical science could bring forth a completely risk-free and more precise procedures.

Notwithstanding, the tools can only be as good as the handler. It is still best to select an experienced and skilled surgeon to increase the chances of a successful operation. Patients need to do their part too in preoperative and postoperative care to achieve the best results.

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