Cataract is among the most widespread eye diseases. According to WHO, up to a third of all visual impairments have to do with cataract. The treatment methods are well-known but can sometimes be traumatizing. Scientists from ITMO and the S.N. Fyodorov Eye Microsurgery Complex spent over 20 years working on reducing the side effects of cataract surgery. As a result, they came up with a technology where a laser is used both to destroy the clouded eye lens and to stimulate the regeneration of adjacent tissue. The researchers gave a detailed description of their method in an article that has been recently published in Optical and Quantum Electronics.
The eye is a very important organ. A healthy eye lets us see in the light and in the dark, read fine print and trace fast objects. But if something goes wrong, the eyesight can rapidly degrade or even disappear completely. One of the common problems is the clouding of the lens, or cataract. The methods for treating cataract are being constantly improved; for one, scientists from ITMO University work on this topic in collaboration with specialists from the S.N. Fyodorov Eye Microsurgery Complex.
The treatment method is surgical and has to do with removing the clouded eye lens and replacing it with an artificial one made of plastic or sapphire. The eye lens is destroyed either with ultrasound or a laser. When using a laser, a special tip is inserted into the anterior chamber of the eye close to the lens, and the laser breaks the lens into tiny fragments that are then removed from the eye. An artificial lens is then put in their place. The problem is that this process damages the adjacent tissue, and the regeneration doesn't always go well."
Andrey Belikov, professor, ITMO University
In the recent decades, many researchers placed their focus on reducing the traumatizing effect of cataract surgery. In 1997, scientists from ITMO University and S.N. Fyodorov Eye Microsurgery Complex, as well as several other research institutions, started to experiment with the use of laser radiation for destroying the cataract. With time, surgeons noticed that the less powerful laser can not only illuminate the surgical field but also stimulate the regeneration of the damaged tissue. So they started conducting experiments aimed at finding the optimal interaction method between the destroying and the illuminating lasers. It turned out that using both lasers simultaneously is the most efficient method. This idea called for elaborate work of optical engineers: as entering the eye with two instruments at the same time is highly undesirable, for the radiation of both lasers it was necessary to use a common optical fiber.
"The simultaneous use of two lasers is good because we get cells that are damaged but not destroyed," comments Prof. Belikov. "And it's very important to stimulate their regeneration at once. This way, the regeneration process takes place in the most favorable conditions."
As of now, the method has already been introduced at the clinic of the S.N. Fyodorov Eye Microsurgery Complex, and almost all of their cataract surgeries make use of two lasers. It has been clinically proved that in the long-term, the use of this method allows to reduce the loss of corneal endothelial cells by 1.8 times in comparison with ultrasonic phacoemulsification, and there have yet been no reports of macular edema or endothelial-epithelial corneal dystrophy.
Belikov, A.V., et al. (2020) Experimental and clinical study of simultaneous dual-wavelength laser action in energetic cataract surgery. Optical and Quantum Electronics. doi.org/10.1007/s11082-020-02298-5.