Femtosecond laser: description, types, features of application and reviews

Let's talk today about what a femtosecond laser is. What are the main principles of his work and how does he help to correct vision?

Bohr's Theory

When in the early nineteenth century science reached a level that could look into the structure of the atom, a new direction arose - quantum physics. The first task was to determine how and why small electrons do not fall on the heavy nucleus of an atom. The previous theory, based on Maxwell's equations, argued that any moving charge emits a field, therefore, loses momentum. Thus, an electron that moves in an orbit around the nucleus must continuously emit and eventually fall on the nucleus. Bohr expressed the idea that in an atom, electrons can only be at certain distances to the center, and a transition from one level to another is accompanied by either emission or absorption of energy. This theory was subsequently explained within the framework of quantum physics. The presence of stationary electronic levels has opened the way for such an invention as a laser (femtosecond including).

Theoretical bases of the laser

Once scientists understood the structure of the atom, they wanted to learn how to control the state of the electron. Under normal conditions, an electron, which for some reason is at a high level of the atom, tends to fill the lower levels, if they are free. During the transition, the energy is emitted in the form of a quantum of light or a photon. But the transition between any two levels generates different quanta of light. But if many electrons pass simultaneously from a higher level to a lower level, then a stream of many identical photons will appear. The applications of this flow are endless. For example, a femtosecond laser removes cataracts. In a yttrium-doped ruby, a level was found with the so-called inverse population: when electrons are more willing to gather at a high level, and then all together go to a lower one. The main components of the laser are as follows:

• The working medium (a substance in which there is a level with an inverse population);
• Pumping (a source that "induces" electrons to accumulate at the inverse level);
• A resonator in the form of two parallel mirrors (they concentrate only those photons that are generated in one direction, and all the others are scattered).

The resulting pulse at the output can be continuous or discrete. A femtosecond laser, for example, is of the second type.

Micro, nano, femto

All these consoles denote part of the whole. Milli is one thousandth of something, for example, a meter. That is, a millimeter is 10 ^-3 meters. Femto prefix means that something weighs or stretches 10 ^-15 times less than a certain unit. Accordingly, a femtosecond laser has a very short pulse. And in every second there are 10 ¹⁵ pieces of impulses. Why do we need such an unimaginably small amount? The fact is that the laser power depends on how much time electrons accumulate on the inverse level. With continuous generation, the power of lasers can not be high. But the shorter each impulse, the higher the yield. Many processes occur much longer, and for a final goal such a short impulse is not noticeable. The receiving system seems to be a continuous laser. In this case, the coherence and output power of the outgoing beam is much higher.

Cataract

Cataract is a clouding of the lens. A person who develops such a visual defect may not even know about it: with the development of cataracts on the edge of the pupil, vision is not disturbed. But if the turbidity occurs in the center of the lens, then you can not notice the loss of vision is impossible. The main causes of this change in the eye are four:

• Harmful radiation in large doses;
• Trauma to the head or directly to the eyes;
• diabetes;
• Strong stress.

The physical reason is the same - the protein contained in the lens of the eye, begins to degrade, break down. This process is called protein denaturation. In the case of the lens, the destruction is irreversible. Earlier, old people with white eyes completely depended on their relatives, because they were actually blind. However, now this disease is successfully treated.

Cataract treatment with surgery

Traditionally, the treatment means such interference in the human body that does not violate its integrity: the sore throat is treated with pills and hot tea, cut with a finger - with ointments and a bandage.

But in this case, radical treatment is an operation. Usually, this word means wounds, stitches that heal for a long time, pain and loss of a normal lifestyle. In the case of cataract surgery, you do not need to be afraid, because the incision is usually very small, 2-3 mm, no blood vessels are cut, local anesthesia.

Stages of the operation:

1. The eyeball is anesthetized with the help of special drops.
2. The iris of the eye is cut (not more than 3 mm long).
3. A special device is inserted into the lens.
4. The device turns the old lens into an emulsion.
5. The emulsion is sucked off.
6. Introduced a new artificial soft lens.
7. The device is removed from the eye.

The procedure lasts no more than 15 minutes, after which the person can already go home.

It is at the stage of transformation of the old lens into an emulsion that a femtosecond laser is used. Ophthalmology knows another example of the use of lasers - correction of nearsightedness and astigmatism. But this is a completely different story.

Advantages of lasers in the treatment of cataracts

Immediately, let's name one significant drawback - this method is quite expensive. However, for all other parameters it is better than previous methods. According to the reviews, the surrounding tissue is less damaged, the transformation into an emulsion is faster, the size of the resulting particles is smaller if a femtosecond laser is used in the operation. Feedback on this operation is extremely positive both from patients and from doctors.

We have already mentioned that with the help of lasers, myopia is also corrected. However, until recently, different equipment was used for this operation and cataract treatment. The patient is the main thing - the quality of the operation, but the clinic, which provides such services, would like to spend on devices not so much money. In this case, the Victus femtosecond laser will help you: with its help, you can do three different operations. In this case, you just need to change the settings.