Corneal disease is a common disease in ophthalmology, and its blindness rate ranks second in the epidemiological survey, of which 80% can be eliminated through corneal transplantation. However, the traditional corneal transplantation has the disadvantages of difficult corneal donor source and rejection. As a new complementary treatment, artificial cornea has become the last hope for these patients to regain their eyesight.
Looking at the global artificial cornea market, Boston artificial cornea has been widely used in the world because of its early start. In 1974, Dohlman et al. first reported the application of the "collar button" artificial cornea made of PMMA in 36 patients. In 1992, the US Food and Drug Administration (FDA) approved the production and sale of Boston keratoprosthesis in the United States. Since 1992, more than 9000 products have been implanted into human eyes.
Boston keratoprosthesis consists of three parts: optical lens column (also known as front plate), back plate and C-shaped titanium ring. The whole artificial cornea needs to be installed on a fresh donor cornea. Once the donor cornea is seriously dissolved, the entire artificial cornea must be replaced.
Reviewing the epidemiology and pathophysiology of corneal dissolution after artificial cornea surgery in Boston, as well as its design and postoperative nursing progress, we can find that the constantly updated design and nursing methods effectively prevent the occurrence of corneal dissolution.
However, "Lucky God" does not care for patients with autoimmune diseases (such as Stevens Johnson syndrome, toxic epidermal necrolysis syndrome and mucosal pemphigoid). Their eyes are very vulnerable to the impact of corneal dissolution, leakage and extrusion, which will lead to decreased intraocular pressure, endophthalmitis, choroidal and retinal detachment, Eye damage caused by these complications may lead to permanent vision loss or loss of eye structural integrity.
So, in recent years, how many patients with Boston keratoprosthesis have experienced corneal lysis? (The following are incomplete data)
○ A Review of Core Melting after Boston Keratoprosthesis (2014) wrote that 20 or more eyes published in British literature in the past decade were classified according to the average follow-up time. The average follow-up time was less than one year, and the cumulative incidence of keratolysis was 1.7%; The cumulative incidence of keratolysis was 7% when the follow-up time was 1-2 years, and the cumulative incidence of keratolysis was 11% when the follow-up time was more than two years. That is, the longer the follow-up, the higher the risk of dissolution.
○ According to the Analysis of Clinical Effects and Postoperative Complications of Boston I Artificial Cornea Implantation, scholars collected 57 patients (61 eyes) who received Boston I Artificial Cornea Implantation in the ophthalmology department of the PLA General Hospital from May 2009 to October 2013. The incidence of carrier corneal dissolution was 16.39%.
It can be said that Boston I keratoprosthesis requires corneal grafts as carriers. It is likely that corneal dissolution will lead to corneal prolapse, infection and even loss of vision. Especially in patients with autoimmune diseases, the rate of anatomical failure is higher. Although the improved design, wearing soft contact lenses and oral collagenase inhibitors are used to prevent corneal dissolution, it is still difficult to avoid for patients with poor ocular surface conditions.
However, this problem will not occur when using Mih artificial cornea. First, Mih artificial cornea is made of artificial materials without donor cornea; Secondly, during the operation, through improved surgical methods (ear cartilage reinforcement, conjunctiva or lip mucosa covering, eye muscle braking, etc.), promote the ocular surface vascularization as soon as possible to maintain the nutrition supply of the anterior lamellar tissue, will also reduce the incidence rate of surrounding tissue dissolution, and greatly improve the anatomical presence rate of the artificial cornea. In the Animal Experiment and Clinical Study of Mihm Domestic Cornea Prosthesis, 23 patients included in the study were followed up for 12 months, and none of them had corneal dissolution, with an anatomical presence rate of 100%.
There are two solutions according to the severity of keratolysis. For mild keratolysis cases without aqueous humor leakage, conservative treatment can be used. Use a corneal bandage lens to prevent evaporation damage and promote epithelial healing, and use drugs according to the doctor's instructions; For severe keratolysis, only fresh corneal carrier transplantation can be used to completely replace Boston keratoprosthesis, which is the only option.
Well, the topic about what needs to be changed when the artificial cornea occurs is shared here today. If you have any questions, you can send a private message in the background or call our official customer service hotline: 400-111-8801 for consultation!