Corneal transplantation is one of the most important operations in ophthalmology. It uses normal and transparent corneal tissue instead of cloudy and diseased corneal tissue to restore or control corneal lesions. This operation has the highest success rate among similar organ transplants at present.
2. There are several types of corneal transplantation, and what are the indications?
Lamellar keratoplasty: It is a partial thickness keratoplasty. During the operation, the diseased tissue in front of the cornea is removed, leaving the underlying tissue as a transplant bed. Therefore, lamellar keratoplasty is feasible for those whose corneal lesions do not invade the deep layer of cornea and whose endothelial physiological function is healthy or recoverable. Clinically, it is often used for superficial corneal macula or corneal dystrophic opacity, progressive keratitis or ulcer, corneal fistula's disease, corneal tumor, and some eyeballs with poor conditions that cannot be transplanted with penetrating cornea. In order to improve the corneal condition, lamellar transplantation should be performed first. Dr. Tan Wei of our hospital also took the lead in carrying out optical lamellar keratoplasty assisted by microkeratome in China. Compared with traditional lamellar keratoplasty, it has the advantages of less complications, good optical enhancement effect and simple operation.
Penetrating keratoplasty: a method of replacing full-thickness turbid cornea with full-thickness transparent cornea. According to the surgical purpose, the indications can be divided into optics, therapy, plastic surgery and beauty. The common indications of optical corneal transplantation are keratoconus, corneal scar caused by various reasons, corneal malnutrition caused by various reasons and corneal endothelial cell failure. The main indications of therapeutic corneal transplantation are suppurative corneal ulcer, ocular chemical injury, silkworm corneal ulcer and corneal limbal degeneration.
Artificial corneal transplantation is a special optical device made of transparent medical polymer materials, which can replace part of corneal scar tissue and restore vision through surgery. Because the rejection of corneal tissue to synthetic materials has not been finally solved, the long-term effect is not good, which often leads to aqueous humor leakage and graft shedding, so it can not be widely used at present. At present, artificial cornea is only suitable for patients who are blind after suffering from various serious corneal diseases, especially those who suffer from total corneal leukoplakia caused by severe chemical burns, and have failed corneal transplantation many times and cannot do other operations.
3. Corneal ulcer drugs are not well controlled. Why do you want a corneal transplant? What are the complications after corneal transplantation in inflammatory stage?
With adequate medication, keratitis is still uncontrollable. Under the dual action of tissue internal pressure and bacterial toxin, corneal stroma is necrotic and exfoliated, forming corneal ulcer. If the ulcer continues to develop deeply, it will cause corneal necrosis and perforation. If corneal transplantation is not performed, inflammation will quickly spread to the eyes, eventually leading to panophthalmitis and loss of eyeballs. At this time, if corneal surgery is performed, drugs can easily enter corneal tissue and eyeball by removing diseased tissue, which is beneficial to control inflammation and save eyeball.
However, because the corneal transplantation at this time is carried out in the inflammatory state of eyeball hyperemia, and the inflammation has not been effectively controlled, the postoperative inflammation may recur; In addition, the rejection of corneal transplantation in inflammatory stage is also high. From the visual point of view, the main purpose of corneal transplantation at this time is to save the eyeball, which is a therapeutic purpose rather than an optical purpose.
4. Who are the most common fungal keratitis? How to treat it?
Fungi often grow on the surfaces of leaves and shells of plants. During the harvest season, farmers are often scratched by leaves or hit by grains, resulting in corneal epithelial abrasions and fungi being brought into corneal wounds. On the other hand, due to busy farm work and poor sanitary conditions, farmers are often not treated in time after being injured, and it is not until fungal keratitis occurs that their eyesight is seriously affected. The main characteristics of fungal keratitis are: slight local reaction, slight photophobia, tears in eyes, sometimes superficial lesions on corneal surface, but severe uveitis reaction, even thick pus behind cornea. Corneal ulcer is grayish white, hard and dry, and its surface is convex, like white toothpaste applied to the corneal surface. Small punctate or dendritic lesions are scattered near the ulcer, and there is an immune ring formed by the interaction between antibodies and fungi around the ulcer.
Fungal corneal ulcer is mainly treated with antifungal drugs, such as 0.25% amphotericin B, natamycin, 10% Dafukang, 1% miconazole, 1% clomiphene, etc. Antifungal drugs, such as propeller capsules, are commonly used all over the body. No matter systemic or local use of corticosteroids, it is forbidden.
Penetrating keratoplasty is a surgical treatment method established in recent years, and its indications are mainly ineffective drug treatment, or serious complications such as corneal ulcer perforation, intraocular content prolapse or secondary glaucoma. It's a rescue operation to save the eye. Because fungal hyphae grow vertically, combined with mycotoxins, proteolytic enzymes and soluble fungal antigens, fungal hyphae can grow very deep and even invade the eyes, and it is difficult to clean up the fungi in the eyes during surgery, so postoperative recurrence often occurs. Therefore, for patients without surgical indications, it is emphasized that antifungal drugs should be used first.
5. Why is there rejection after corneal transplantation?
Corneal transplantation is the first successful organ transplantation, because the normal cornea has no blood vessels and lymphatic vessels, and the graft is not easily recognized by the patient's immune system, so it generally does not cause rejection. Just as blood transfusion between different individuals may cause allergic reactions, allogeneic corneal transplantation may also cause immune rejection, especially when the graft is large, inflammation, corneal neovascularization and corneal tissue antigens are very different, allogeneic corneal antigens can be recognized by the patient's immune system, which further produces sensitized lymphocytes and anti-graft antibodies, which then attacks and rejects the graft, eventually leading to graft degeneration, turbidity and scar formation, leading to blindness.
6. Which eye diseases are prone to rejection in corneal transplantation?
The following factors will increase the possibility of rejection after corneal transplantation: ① There are new blood vessels in the corneal stroma of patients, because new blood vessels make it easier for immune cells to reach the graft and recognize and attack foreign antigens. ② Large grafts are prone to rejection because they carry strong effective antigens and are close to the corneal limbus of patients. ③ Patients are highly sensitive and prone to rejection. ④ Other factors, such as inflammation after transplantation and hyperemia of eyes, may also induce rejection. Specifically, patients with severe neovascularization (such as corneal leukoplakia, acid and alkali burns), uncontrolled corneal inflammation, herpes simplex keratitis, and the need for a second corneal transplant after the first corneal transplant are more prone to rejection after corneal transplantation.
7. How to prevent rejection after corneal transplantation?
The prevention and treatment of corneal transplant rejection should be based on prevention and treatment. Rejection after corneal transplantation is generally impossible to occur within 10 days, and rejection rarely occurs within 2-3 months after operation with sufficient corticosteroids. The peak time of rejection was 4- 18 months after operation, and then the incidence decreased gradually. Rejection reaction is often induced by suture removal, corticosteroid reduction, cold, etc. The main symptom is decreased vision. Eyeball congestion, fear of light and tears, corneal graft opacity. If the above symptoms appear, you need to come to our hospital for a follow-up visit immediately.
The clinical treatment measures of rejection after corneal transplantation mainly include: ① corticosteroids: this is the most important drug to treat rejection at present. In the application process, we should adhere to the principle of adequate, regular and slow withdrawal of drugs, increase the dose after rejection, and pay attention to complications that may cause intraocular pressure to rise. ② Application of cyclosporine A: This is an effective immunosuppressant, which is generally used after glucocorticoid therapy is ineffective. ③ Other drugs, such as prostaglandin inhibitors, indomethacin and aspirin, have certain therapeutic effects on immune rejection. Cytotoxic immunosuppressants such as azathioprine and cytarabine also have certain application value, but they should be used with caution under the guidance of doctors, because these drugs may cause serious bone marrow suppression and systemic infection. ④ If rejection has occurred and the treatment is ineffective, and the graft is turbid, a second corneal transplantation can be considered.
8. What are the precautions after corneal transplantation?
Corneal transplantation itself is only a part of corneal transplantation, and postoperative treatment and self-care are the important contents of corneal transplantation.
1. Regular examination: once a week after discharge, once a month after one month, and once every three months after corneal suture removal, without special circumstances, so as to reduce long-term postoperative complications. Medication guide: Dibishe eye drops, 4 times a day; 1% cyclosporine eye drops, 4 times a day; Point nose cream, once a day before going to bed. 1.5 months later, three times a day, three months later, twice a day, two weeks later, it was reduced to 1 time, and it was completely stopped after four months.
2. Corneal suture removal time: the suture of penetrating keratoplasty is generally six months to one year after operation; Lamellar keratoplasty usually takes 2~3 months after operation, and the specific time will be decided by the doctor.
3. Pay attention to the occurrence of rejection; Rejection often occurs 1~2 months after operation, but some patients also have rejection several years after operation; Therefore, if the patient feels jealous and painful, his vision suddenly drops, and the corneal graft is cloudy, he should go to the hospital immediately.
4. If you can't come to our hospital in time, you should go to the local hospital for treatment immediately, and it is best to go back to our hospital for a follow-up visit if possible. The general treatment is: Dianbishu eye drops once an hour; 1% cyclosporine eye drops, once every 2 hours; Canon eye ointment, once a day before going to bed; Methylprednisolone 20 mg was injected under the ball every 3 days 1 time, or dexamethasone injection 2.5 mg was injected under the conjunctiva (every other day 1 time); At the same time, hydrocortisone 100 ~ 200mg was dissolved in 500ml or 1000ml glucose solution for intravenous drip. About 7 days, according to the transparency of the graft, the hormone can be taken orally for a period of time, and eye drops will continue, but the frequency will gradually decrease.
5. When dropping eye drops, the dropper shall not contact the corneal graft, and two or more eye drops shall be used alternately, with a few minutes interval each time, so as to ensure the concentration of the drug in the eye. Eye drops should be kept in a cool and dark place.
6. Dietary guidance: properly supplement nutrition, enhance the body's resistance, eat more fruits and vegetables, and keep the stool unobstructed. Eat less spicy and greasy food.
7. Activities and rest:
Pay attention to eye hygiene, don't rub your eyes, and wear protective glasses when going out to avoid hurting your eyes.
Can't swim, prevent infection, avoid sun and hot compress, and protect corneal grafts.
Avoid heavy physical labor within one year after operation, and have a complete course of treatment for three months.
The graft is not sensitive within one year, and it is easy to get hurt. Care should be taken to avoid friction. If you are a patient with herpes simplex virus inflammation, you should pay attention to prevent colds, upper respiratory tract inflammation and overwork after surgery. Don't smoke to prevent keratitis from recurring.