Cornea transplant

Corneal transplantation is a Surgical intervention aimed at replacing a cloudy or diseased cornea with another in good condition, to regain vision or prevent the possible inflammation or infection of the cornea from passing into the eye.

To carry out the corneal transplant, we have different techniques, depending on the origin of the problem with the cornea or its anatomical state. When the cornea has all its layers altered or before a perforation, it is necessary to transplant all the layers, it is what we know as Transplant or Penetrating Keratoplasty. When the damage affects only part of the layers of the cornea, a Transplant or Selective Keratoplasty, only from damaged layers.

Currently, in most cases, we perform selective transplantation since it is less traumaticHas less complications graft viability is longer and visual recovery is faster.

Cornea transplant

Corneal transplantation is a Surgical intervention aimed at replacing a cloudy or diseased cornea with another in good condition, to regain vision or prevent the possible inflammation or infection of the cornea from passing into the eye.

To carry out the corneal transplant, we have different techniques, depending on the origin of the problem with the cornea or its anatomical state. When the cornea has all its layers altered or before a perforation, it is necessary to transplant all the layers, it is what we know as Transplant or Penetrating Keratoplasty. When the damage affects only part of the layers of the cornea, a Transplant or Selective Keratoplasty, only from damaged layers.

Currently, in most cases, we perform selective transplantation since it is less traumaticHas less complications graft viability is longer and the visual recovery is faster.

What is a cornea transplant?

Corneal transplant it is a surgery that is performed when the cornea loses its transparency and does not let light pass into the retina. The consequence is loss of vision

The most frequent causes of loss of transparency of the cornea are: 

  • Corneal infections (Herpetic keratitis, ulcers bacterial or fungal).
  • Corneal degenerationsLike Keratoconus or endothelial degenerations after cataract surgery.
  • Corneal dystrophies, most of hereditary transmission, such as Fuchs' endothelial or lattice or granular dystrophies.
  • Trauma facials with involvement of the cornea or chemical caustications by acids or legia. 

In these cases we know that the corneal tissues lose its lamellar structure and with it, the transparency irreversibly. The The only possible treatment will be to replace that diseased cornea with a corneal transplant, also called keratoplasty.

El cornea transplant (keratoplasty), is the most successful of tissue transplants. The average success rate depends on the cause that caused the loss of transparency of the cornea. For example, corneal transplants by degeneration secondary to cataract interventiony those due to keratoconus, are the ones that have higher rate of good results. However, transplants secondary to chemical causticizations or immunological processes, have worse results.

When should a corneal transplant be done?

The indication to perform a cornea transplant is due to 2 main reasons

  • La irreversible loss of vision by corneal diseases that cause its opacification.
  • El risk of not preserving the anatomical structure of the eyeThat is, situations of corneal perforation or infections of the cornea that can spread into the eye.

Among the main causes of corneal transplantation we find the bacterial infections, fungal o viral are frequent causes of ulcerations y severe corneal disturbances. Alterations of corneal curvature (keratoconus), degenerations that may appear after cataract surgery (corneal edema or swelling), and some degenerative processes, can affect corneal transparency.

cornea transplant

Some corneal diseases They are hereditary, and can cause blurred vision and loss of vision and with it, cause the need for a cornea transplant.

Types of transplant of conrea

Among the various types of corneal transplant we find two:

Penetrating cornea transplant

The cornea It is in the most anterior area of ​​the eye and is characterized by being transparent, to let light pass into the retina, where the visual process will start.

When a lesion on the cornea that breaks down all the layers that make it up, transparency will be irreversibly lost. It is in these cases when it is necessary to indicate a transplant of the entire thickness of the cornea, "penetrating transplant", generally with a diameter between 8 and 8.5 mm. Less than the diameter of the receiving cornea (that of the patient), around 12 mm in diameter. In fact, the donor cornea is spliced ​​with the patient's cornea ring that we leave behind to be able to suture it.

La advantage of this surgery is that it is usually the only option in severe cases of corneal pathology. The main disadvantage is that the recovery is slower and more complex and there is more risk of rejection immunological

Lamellar cornea transplant

It consists of a selective corneal transplant where we transplant only the corneal layer that is damaged. There are 2 types of lamellar transplantation: the anterior and the posterior.

Lamellar anterior

The anterior lamellar corneal transplant is the surgical technique that we use to transplant the previous layers of the cornea and according to the depth to which the corneal lesions are, we divide it into 2 basic techniques:

  • Superficial anterior lemelar (SALK)
  • Deep anterior lamellar (DALK)

Posterior or endothelial lamellar

In the posterior Lamellar transplant or endothelial transplant, we substitute the deeper or posterior layers of the cornea, the endothelium and / or the Descemet

The surgical techniques for posterior lamellar or endothelial corneal transplantation they are:

  • DMEK: When you selectively transplant the corneal endothelium.
  • DSAEK: When the endothelium and the Descemet.

How is the corneal transplant operation?

The corneal transplant tissue comes from an eye bank. The process begins with requesting a cornea to be transplanted. The eye bank is notified and if there is a donation due to the death of a donor, the surgical intervention can be arranged. The operation consists of implanting the central and transparent part of the cornea donor, usually 8 to 8.5 mm in diameter, in the patient's eye.

Currently, you can select part of cornea donor that we want to transplant, Is not always all cornea (penetrating transplant), sometimes only such a part is necessary, if we have a patient who has suffered a viral corneal affectation that left a scar in the most anterior layers of the cornea, it will suffice to replace, with transplant, Those damaged layers, respecting the rest of the cornea, is what we call lamellar transplant. In the same way, corneal diseases that only affect the corneal endothelium, the innermost layer of the cornea, can be cured by selective transplantation of this layer, it is the endothelial transplant.

In all the types of transplantation that we have described above, the corneal tissue to be transplanted must be prepared, as well as the recipient cornea, that of the patient. In a penetrant transplant, you have to carve the graft diameter (8 / 8.5 mm), with a trepan that cuts it precisely. In the same way, we must carve the "window" of the patient's cornea, with a trepan and retaining a corneal ring in which the graft is sutured. The carving is a diameter similar to that of the graft or somewhat larger, 0.5 mm. The donor cornea is sutured with the patient's cornea ring, with a very fine nylon thread, using loose stitches, continuous suture or combining both.

When it comes to a selective transplant, the donor cornea layers must be dissected to replace the damaged cornea of ​​the patient. They are very delicate maneuvers that are performed with microkeratomes. This dissection is complex and requires very expert surgeons since the tissue to be transplanted can be easily damaged, making the surgery fail.

In rural areas of India, families in charge of a blind minor frequently isolate and deprive him/her of the care and attention they provide to their other children; such situation becomes even more severe among lower-caste families, orphans and if the blind child is a girl. previous keratoplasties, it is necessary to suture the graft over the recipient cornea, while in the posterior lamellae, we insert the graft into the eye and it is fixed in the correct position without the need for suturing. It is a very delicate process and requires the skill of the surgeon. The great advantage is that the recovery is much faster than penetrating keratoplasties.

El selective transplant presents many and advantages as retains part of the patient's cornea, which allows improve results and a faster recovery. The only problem is that requires a very skilled surgeon and more sophisticated technology and that makes the process more expensive and not all ophthalmologists have it.

This  surgery It is usually done in a way ambulatory, with Anesthesia local y sedation, so that the patient can return home the same day of the intervention.

Corneal transplant postoperative

Vision recovery after corneal transplant can take time. Usually recovers from a 20% to 30%, in the first days and the rest depends a lot on the disease causing corneal opacification or the technique performed, and may need up to one year after surgery. In general, you have to have careful with physical exercise and activities that require visual effort. Usually we don't cover our eyes and although the recovery is progressive, after the first week already you can do activities that allow the patient to be self-sufficient.

As in the rest of the transplants, the donor tissue can be rejected, especially when the endothelium is transplanted, both in penetrating keratoplasties and in posterior lamellar ones (DMEK and DASEK). The major signs of rejection They are a eye redness, pain worsening vision. If this occurs, it must be go quickly to the ophthalmologist, even though several years have passed after the surgery. 

postoperative cornea transplant

Cornea transplant in Área Oftalmológica Avanzada

Until recently, in most cases the penetrating cornea transplant, of all its layers, very aggressive, with a higher risk of failure and a long recovery time. For this reason, the lamellar transplant techniques, only of the altered layers, which reduces risk and recovery time

En Our center has been pioneers in modern lamellar techniques, participating in the design of the sophisticated instruments for its realization, such as Moria ™ Microkeratome for Anterior Lamellar Transplantation and Endothelial Transplantation or DSAEK-DMEK

On many occasions we find the condition of the cornea and the ocular surface, very deteriorated and it is necessary to perform a previous reconstruction surgery. Treatments must be carried out to regenerate the ocular surface and prepare the ground for guarantee that the cornea transplant is effective and safe. These regeneration maneuvers consist of the amniotic membrane implant, limbo transplant o cell culture and stem cell implants. They are very sophisticated techniques that require de highly experienced surgeons, such as Dr. Vergés, one of the first ophthalmologists in Europe to perform this type of treatment and means that are only available in large hospitals or highly specialized centers, like in our case that in the Dexeus University Hospital, we have all this technology and specialized personnel to carry out these techniques. There are many patients, national and international, who come to our center and who have benefited from these advances that have been able to recover their vision.

FAQ

What is the cornea?

The cornea is a tissue that is found in the most anterior area of ​​the eye and is characterized by being transparent, to let light pass into the retina, where the visual process will start.

The corneal diseases that, directly or indirectly affect their transparency, will cause a interference with the passage of light into the eye, the result end one loss of vision.

What can damage the cornea?

Knivespencils and other sharp objects can cause serious corneal injuriesFireworksbattery explosions y Chemicals toxic, especially alkaline and legia, can also cause severe corneal scars.

In fact, corneal involvement is the first cause of ophthalmologic urgency. When the injury is due to a chemical product, necessary wash the eye with water or saline abundantly. Many corneal injuries can be prevented with the use of protective goggles and taking precautions when handling dangerous substances.

Diseases that damage and cloud the cornea

Various diseases can cause damage that causes loss of transparency of the cornea, irreversibly and which makes it necessary to perform a cornea transplant to regain vision.

The most frequent diseases are corneal herpes virus infectionsulcers bacterial or fungal, immune diseases of the skin such as Pemphigoid, or in cases of rheumatic ulcers or other collagen diseases, like Lupus or dry eye by Sjögren.

Why is the cornea rejected?

The rejection is because the immune recognition mechanisms detect that the transplanted corneal graft does not belong to the host tissues, of the person to whom the transplant has been performed. They do not recognize it as their own and initiate a defense reaction aimed at eliminating that tissue, as if it were an invasive microorganism.

We know that on the cornea, the layer with the highest immune load is the endothelium. For this reason we try to preserve the patient's endothelium for avoid rejection. In previous lamellar keratoplasties, we always try to maintain the patient's endothelium and current techniques allow all layers to be dissected, down to the endothelium, barely 20 microns, and to replace everything else. With this surgery, we managed to reduce transplant rejection and that grafts exceed 10-15 years of survival, compared to 5-10 before.

Your Order
Corneal diseases and transplants
Article name
Corneal diseases and transplants
Description
Discover here everything you need to know about corneal transplantation. If you have to submit to this surgery we inform you.
Composer
Name of the editor
Área Oftalmológica Avanzada
Editor's logo