The sequelae of laser eye drilling

Laser eye drilling is very harmful to people's eyes. Such strong light will cause some stimulation to the nerve tissue inside the eye. If this continues for a long time, it will cause the naked eye to feel blurred vision, or even temporary blindness. Therefore, these sequelae are relatively serious and should be taken particularly seriously.

There are three types of damage to human eyes caused by laser: 1. Damage to eye nerves caused by strong light. Laser is a kind of high-density light energy, and its single wavelength is monochromatic light. Weak laser will feel very dazzling when it is directly shone on the naked eye. Slightly high-power laser will cause temporary blindness. High-power light intensity can directly damage human eye nerves and cause blindness. This also applies to visible light, infrared or ultraviolet non-visible light, which is invisible to the human eye. All of them have no sensory stimulation to human eye nerves.

2. When the light energy reaches a certain level, it will generate high temperature on the object, which will directly cause burns to the eyes. When the laser power reaches a certain level, it can instantly vaporize the steel plate, which is no problem for the eyes. This should also be very easy to understand.

3. Some specific lasers have a particularly strong absorption effect on specific materials. For example, the near-infrared laser in the 1064NM band has a laser characteristic that it absorbs water very strongly. If it is directly irradiated into the human eye, it will absorb the moisture in the human eye, which will cause great damage to the eye. In fact, there is no radiation if the laser does not come into contact with a specific object. For the human body, the main harm of the laser is the sensory stimulation to the human body, the burns caused by the high energy, and the absorption of water by the specific wavelength

The "excimer laser surgery" that people generally refer to should be called "excimer laser refractive corneal surgery", which mainly includes three types of procedures:

(1) Excimer laser photorefractive keratectomy (PRK) is the earliest method used in clinical practice. PRK is currently considered safe and effective in correcting low to moderate myopia, hyperopia and astigmatism, but it is rarely used due to complications such as postoperative pain and refractive regression.

(2) Laser in situ keratomileusis (LASIK), which is the current mainstream procedure. It cuts the stromal layer under the corneal flap, maintaining the integrity of the corneal epithelium and anterior Descemet's membrane, and can avoid most complications of PRK. The characteristics are that it broadens the correction range of myopia, there is no pain during and after the operation, the vision recovers quickly, and no corneal cataracts are left. During the operation, a micro-knife is used to cut a thin corneal flap with a pedicle on the cornea. The flap is then opened, laser cutting is performed on the flap, and then the flap is restored to its original position. This can be used for low, medium and high myopia.

(3) LASIK also has defects caused by the corneal flap, namely, corneal flap wrinkles, displacement, epithelial implantation under the corneal flap, astigmatism and excessive cutting, which cause corneal ectasia, keratoconus, etc. (According to a survey, 80% of keratoconus patients are related to LASIK). For patients with high relative myopia who have high corneal myopia and ASIK is limited, but for patients with high myopia whose corneal flap is thick enough, LASIK is still the first choice.