Cover News reporter Qiu Tian
Recently, the Eye Refractive Surgery Center of West China Hospital of Sichuan University successfully performed a binocular stromal lens implantation operation on a hyperopia patient, which corrected the height of the patient for more than 20 years farsighted. This is also the first case of lens implantation to correct hyperopia performed by West China Eye Refractive Surgery Center in Sichuan, realizing the reuse of normal cornea. After multiple re-examinations, the patient’s binocular visual acuity reached 4.9, and it has remained stable for more than three months.
What is a stromal lens? The corneal stroma lens is derived from the corneal tissue removed during SMILE full femtosecond laser myopia correction and is a part of the normal cornea. Matrix lenses are obtained from the corneas of healthy adults, with the transparency and elasticity of normal corneas, similar to contact lenses, and can be used for refractive correction, so they are also called “matrix lenses”.
It is understood that corneal materials are scarce in my country, and most of them are used to treat patients with severe corneal disease. The base lens material is laser-polished corneal stroma (part of the cornea) in the form of a convex lens. With the development of femtosecond laser surgery in recent years, the reuse of lenses based on corneal materials has gradually become a research and application hotspot in the field of cornea and refraction. Lens implantation technology not only depends on in-depth understanding of corneal materials, but also inseparable from researchers’ accumulation of surgical design and related experience.
Hyopia, as a type of refractive error, has a great impact on the lives of adults. Since objects are imaged behind the retina, intraocular adjustment is frequently activated during daily eye use, and visual fatigue often occurs. Especially after entering middle age, visual fatigue is obvious, and people with high hyperopia are deeply touched.
Currently the commonly used surgical correction method is excimer laser, which corrects vision by ablating tissue, but the risk of corneal ectasia caused by the obvious reduction of tissue thickness is one of the important issues to be considered in surgery.
Compared with excimer laser surgery, the advantages of lens implantation to correct hyperopia are obvious. Reasonable lens implantation can make the transition around the lens smoother, and the process is reversible, and the lens can be removed if it is not suitable. More importantly, lens implantation has relatively little mechanical impact on the native cornea. Because excimer ablation corrects hyperopia, the flattened surface around the central protrusion needs to be polished. Therefore, the ablation of the entire cornea will ablate more corneal tissue for myopic patients with the same diopter change. Therefore, from the perspective of safety, lens implantation corrects hyperopia. Surgery is superior to excimer laser surgery for hyperopia correction.
Although there are obvious advantages, lens implantation surgery to correct hyperopia also means higher requirements. Not only do the diopter matching of the donor and the recipient need to be fully considered before surgery, whether it is necessary to increase or decrease PTK or PRK to achieve laser ablation, but the surgery requires the doctor to complete it in a short period of time, that is, in the application of the lens, the interlayer processing, and the surrounding of the lens. There is enough experience in the management to reduce postoperative complications.
West China Ophthalmology Refractive Center is committed to the expansion of the clinical application of matrix lenses. After initial results have been achieved in the treatment of infectious and dilated keratopathy, the use of lenses has been extended to hyperopia correction, so that the refractive index of hyperopia can be improved. The light correction is changed from the original subtraction to the addition mode. The lens implantation correction surgery implemented this time uses the laser surgery mode to create a matching matrix bed, and then implants the lens, the purpose is to create a smoother transition zone and arc surface to obtain better visual quality.
The surgery to correct hyperopia with lens implantation needs to be completed in a relatively short period of time. In addition to accurate preoperative measurement and diopter matching, the doctor also needs to have sufficient experience in laser polishing and accurate lens alignment.
There are few reports on lens implantation at home and abroad, but they are all in the initial stage of exploration. This operation is a milestone in the reutilization of corneal stroma lens in the West China Eye Refractive Surgery Center. It is believed that it is expected to be further promoted on the basis of more attempts and accumulation of more experience.
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