Eyes are an indispensable and important organ for people to work, live and study. 80% of people’s information and more than 95% of their work must be obtained or assisted by their eyes. Without eyes, the world is dark. Eyes are delicate and delicate tissues, and people often describe them as "no sand can get into your eyes". Therefore, eyes have become the focus of people's protection and are people's "second life." Due to the important position of the eyes, the emergence of any new technology will first attract the attention of ophthalmologists. It is not surprising that when lasers first appeared, the first medical field used was ophthalmology.
Laser "wrench" for vision correction
For unknown reasons, more and more people are suffering from myopia. Some of these patients feel that wearing glasses is unsightly, or affects some sports activities. The popular contact lenses are not only too cumbersome, but also have the risk of causing new inflammation.
Since the human eye can adjust the focal length of the image just like a camera, why can't it be adjusted by rotating the thread like a camera lens? This is theoretically true and has been conceived a long time ago, but it just lacks the "wrench" to adjust the "thread" - a precision eye surgery instrument.
With the development of laser technology, this idea has been revived and has been successful in animal experiments and clinical trials. This means that the end of the 20th century will provide us with a vision correction technology that can replace glasses.
In 1983, researchers at Columbia University demonstrated that corneal tissue could be gradually removed by directly breaking molecular bonds. In 1988, International Business Machines Corporation's Watson Research Center demonstrated for the first time that corneal ablation using excimer laser is very precise, reaching the nanometer level, and causing minimal damage to surrounding tissues. This is because excimer lasers "cut" cold by breaking the chemical bond between two molecules. Animal experiments have shown that with the cooperation of microscopy technology, this technology can even correct the refractive value of the eye by degree, which is simply wonderful.
In order to more accurately control the position and depth of corneal incision, Professor Doi Kenjun of the University of Tokyo and Professor Dorothy Kazuzu of the School of Medicine introduced the excimer laser corneal incision method with a laser scanning system. . Its characteristic is that it uses a helium-neon laser to scan the corneal surface, and after measuring the shape, it uses an excimer laser to remove it, thus improving the accuracy and safety of corneal surgery.
Prior to this in September 1988, the former Soviet Union had developed a fully automatic laser eye treatment machine that used thermal evaporation to perform PRK surgery. This kind of surgery was performed in the former Soviet Union for 80 years. For example, 10 cases were done in Germany, and it was said that they were all successful.
Good news for glaucoma patients
Glaucoma is a disease that middle-aged people are susceptible to, and its clinical symptom is increased pressure in the eyeballs. If left untreated, it often leads to blindness. The traditional treatment is surgical incision and decompression.
The U.S. Food and Drug Administration has approved two technologies that use lasers to treat glaucoma.
One is the holmium laser treatment operation for glaucoma performed by Senraixi Technology Company. During the operation, the doctor inserts a needle into the conjunctival cortex and uses quartz optical fiber to deliver the holmium laser to the sclera. By controlling the emitted laser to be at right angles to the direction of the optical fiber, a small hole with a diameter of 0.2 to 0.3 mm is burned on the sclera. Allows an agent to flow into the cavity between the conjunctiva and sclera to maintain appropriate intraocular pressure. This holmium laser has an output wavelength of 2.10 microns and an energy of 0.1 joules per pulse.
Apolis-based Rashag Company uses a neodymium-doped yttrium aluminum garnet laser to perform thermal shaping of small columns. This is a surgery to reduce the pressure inside the eye in patients with unconstrained glaucoma. The company's laser is said to be the only neodymium-doped yttrium aluminum garnet pulsed laser device available to ophthalmologists.
Light "needle" cleverly removes cataract
Cataract is also a common eye disease in humans. It is characterized by the production of a glassy or gelatinous, translucent and transparent substance in the lens of the human eyeball. Opaque objects directly block the passage of light.
Before 1980, the only way to treat cataracts abroad was to surgically open the posterior membrane, which was an operation that required full anesthesia. Our country uses a "needle pulling method" surgery, which is a kind of surgery that pushes the cataract capsule under the vitreous body. It once enjoyed a high reputation internationally.
Later, researchers from the University of Paris and the University of Bern in Sweden discovered that the use of laser-induced shock waves was extremely useful in clearing secondary cataracts.
They used a neodymium-doped yttrium aluminum garnet laser with a wavelength of 1.06 microns to emit nanosecond or picosecond pulses to focus the infrared laser on or near the opaque back film, thus Use the shock wave generated by the laser to tear it apart.
After laser treatment, the patient’s vision improves almost instantly. More than 200,000 surgeries called posterior capsulostomy are performed each year in the United States. Unlike traditional surgeries that cost $2,000 in the early days, laser surgery costs no more than $1,000 and does not require general anesthesia or hospitalization at all.