Corneal Transplantation (Keratoplasty)

What Is the Cornea and What Role Does It Play in Vision?

The cornea is a transparent, dome-shaped tissue located at the very front of the eye. As the first point of contact between the external environment and the eye, the cornea both serves as a protective barrier for the eye and ensures that light is refracted correctly for clear vision. A healthy cornea is fully transparent, has a smooth surface, and a regular curvature. These properties are of great importance for the image to be properly focused on the retina.

During the vision process, light first passes through the cornea. The cornea provides a significant portion of the eye’s total refractive power, helping the image become clear. If the structure of the cornea becomes damaged, thins, or loses its transparency, light is not refracted properly, and this can lead to complaints such as blurred vision, shadowing, glare, or double vision.

The cornea is also a layer that protects the eye against external factors. It forms a physical barrier against harmful factors such as dust, microorganisms, and foreign objects. Working together with the tear film, it helps keep the ocular surface moist and reduces the risk of infection.

Keratoconus, corneal infections, trauma, genetic disorders, or certain previous eye surgeries can cause permanent damage to the cornea. In such cases, the cornea may lose its transparency or its shape may become distorted. In advanced-stage patients, corneal transplantation (keratoplasty) treatment may be required to restore vision.

Corneal health is one of the fundamental elements of quality, clear vision. Therefore, when complaints such as blurred vision, glare, or deterioration in night vision arise, a detailed eye examination is important for the early detection of potential corneal diseases.

What Is Corneal Transplantation (Keratoplasty) Treatment?

Corneal transplantation (keratoplasty) is the procedure of replacing corneal tissue that has lost its transparency or become structurally damaged due to various diseases or trauma with healthy corneal tissue obtained from a donor. The main goal of this treatment is to improve visual quality, restore the cornea’s transparency, and make the patient’s daily life more comfortable.

The cornea is one of the most important building blocks of vision. A healthy cornea allows light to enter the eye properly and form a clear image on the retina. However, in some diseases, the cornea thins, its shape becomes distorted, or it loses its transparency. In this case, glasses, lenses, or laser treatments are not sufficient, and corneal transplantation becomes one of the most effective treatment options.

Corneal transplantation is not a surgery in which the entire eye is replaced. Only the damaged corneal tissue is removed and replaced with healthy corneal tissue. Today, thanks to advanced surgical techniques, in most patients only the diseased layer is replaced, achieving faster healing and more favorable outcomes.

This treatment can be applied particularly in the following situations:

• Advanced-stage keratoconus
• Corneal scars and opacities
• Corneal edema
• Trauma-related corneal damage
• Corneal disorders resulting from previous surgeries
• Permanent corneal damage caused by certain infections Corneal transplantation surgery is generally performed under local anesthesia, and most patients can be discharged the same day. Eye drops and regular check-ups after the surgery are of great importance for the healthy progress of healing.

With advances in technology, corneal transplantation surgeries can now be performed with much more precise techniques. Thanks in particular to layered corneal transplantation methods, it has become possible to replace only the problematic section while preserving healthy tissue. This both shortens the healing time and reduces the risk of complications.

Corneal transplantation, when applied with proper patient selection and correct surgical techniques, is an effective treatment method that can provide a marked increase in visual quality. Therefore, in cases where corneal disease has progressed and other treatment options are insufficient, corneal transplantation offers patients an important solution.

In Which Cases Is Corneal Transplantation Performed?

Corneal transplantation (keratoplasty) is a treatment method applied in cases where the cornea has lost its transparency, its structure has become distorted, or permanent damage that seriously affects vision has occurred. While glasses, contact lenses, or other surgical methods are sufficient for some conditions, in cases where corneal tissue has been damaged irreversibly, corneal transplantation becomes the most effective solution.

The main conditions that may require corneal transplantation are as follows:

Keratoconus

Keratoconus is a progressive disease in which the cornea thins and bulges forward into a cone shape. In the early stages of the disease, methods such as glasses, lenses, or corneal cross-linking may be sufficient. However, in advanced stages, when the cornea becomes too thin or adequate vision cannot be achieved even with rigid lenses, corneal transplantation may be required.

Corneal Scars and Loss of Transparency

Permanent scars may form on the cornea following corneal infections, trauma, or certain eye diseases. These scars can seriously reduce vision by preventing light from entering the eye properly. In such cases, replacing the damaged corneal tissue can improve visual quality.

Corneal Edema

Corneal edema occurs when the cells in the inner layer of the cornea fail to perform their function. In this case, the cornea swells and loses its transparency. Corneal edema can develop especially after certain cataract surgeries or in diseases such as Fuchs’ endothelial dystrophy. In advanced cases, corneal transplantation may be the most effective treatment.

Trauma-Related Corneal Damage

Impacts to the eye or cutting or penetrating injuries can cause permanent damage to corneal tissue. If the damage has distorted the cornea’s transparency or shape, corneal transplantation can help restore vision.

Problems Related to Previous Eye Surgeries

In rare cases, the corneal structure may become distorted or transparency may be lost following certain eye surgeries. In such cases, corneal transplantation may be required.

Genetic or Structural Corneal Diseases

Some corneal diseases may be congenital or genetic in origin. Over time, these diseases can distort the cornea’s structure, causing vision loss, and corneal transplantation may be required in advanced stages.

The decision for corneal transplantation is made after a detailed eye examination and advanced tests. Transplantation is not necessary for every corneal patient. Thanks to today’s advanced treatment methods, many patients can be treated before reaching the transplantation stage. However, in cases where the cornea can no longer perform its function and vision is seriously affected, corneal transplantation offers an effective option for improving visual quality.

Who Is Eligible for Corneal Transplantation?

Corneal transplantation (keratoplasty) is a treatment method applied to patients with permanent corneal tissue damage that has seriously affected their visual quality. However, transplantation is not necessary for every corneal patient. The decision for corneal transplantation is made following a detailed eye examination, corneal mapping, and evaluation of other tests.

Corneal transplantation can generally be applied to patients with the following conditions:

Patients with Severely Reduced Vision

In patients whose cornea has lost its transparency or whose shape has become markedly distorted, light cannot reach the eye properly, and visual quality decreases significantly. If adequate vision cannot be achieved with glasses or contact lenses, corneal transplantation may be considered.

Patients with Advanced-Stage Keratoconus

In advanced stages of keratoconus, the cornea may become excessively thin or irregular. In patients who cannot achieve adequate vision even with rigid lenses, or who cannot tolerate lens use, corneal transplantation may be a suitable treatment option.

Patients with Corneal Edema or Endothelial Failure

When the cells in the inner layer of the cornea fail to perform their function, the cornea swells and becomes cloudy. These patients may experience more pronounced blurred vision, particularly in the morning hours. In advanced cases, corneal transplantation may be necessary.

Patients with Corneal Scars or Marks

Permanent scars may form on the cornea following previous infections, trauma, or certain eye diseases. If these scars affect vision, corneal transplantation can be performed.

Patients Who Have Experienced Corneal Trauma

If the corneal structure has been distorted and vision affected as a result of impacts or injuries to the eye, corneal transplantation can help restore vision.

Who May Not Be Suitable for Corneal Transplantation?

In some cases, corneal transplantation may not be suitable, or different treatments may need to be planned first. For example:

• In advanced glaucoma patients whose intraocular pressure cannot be controlled
• If there are diseases causing serious vision loss in the back layer of the eye
• In patients with an active eye infection
• In certain special situations where treatment compliance is not possible In such cases, the underlying problems must first be treated.

The most accurate decision for corneal transplantation is made through a detailed examination and personalized evaluation. Since each patient’s corneal structure, disease stage, and visual expectations differ, the treatment plan is also determined on an individual basis.

What Are the Types of Corneal Transplantation?

Corneal transplantation (keratoplasty) is not a surgery performed with a single method. Thanks to today’s advanced surgical techniques, different transplantation methods are available that allow only the damaged portion of the cornea to be replaced. The choice of these methods is determined by the type of disease, which corneal layer is affected, and the patient’s overall eye health.

Corneal transplantation is essentially divided into two main groups: full-thickness corneal transplantation and layered (lamellar) corneal transplantation.

Full-Thickness Corneal Transplantation (Penetrating Keratoplasty)

Full-thickness corneal transplantation is the procedure of replacing all layers of the cornea. In this method, the damaged corneal tissue is completely removed and replaced with healthy cornea obtained from a donor.

This method is generally preferred in:

• Cases where the entire corneal tissue has been damaged
• Deep corneal scars
• Advanced trauma
• Certain previously unsuccessful corneal surgeries Full-thickness transplantation is a reliable method that has been used for many years. However, since the entire cornea is replaced, the healing process may be somewhat longer compared to layered transplants.

Layered Corneal Transplantation (Lamellar Keratoplasty)

In layered corneal transplantation, only the diseased layer is replaced, and healthy tissue is preserved. This method is more advantageous for many patients today because:

• Healing time may be faster
• The risk of tissue rejection may be lower
• The eye’s natural structure is better preserved Layered transplants are further divided into different techniques.

DALK (Deep Anterior Lamellar Keratoplasty)

In the DALK method, the front layers of the cornea are replaced, while the innermost layer is preserved.

This method is particularly preferred in conditions such as:

• Keratoconus
• Corneal diseases affecting the front layer Since the patient’s own inner corneal layer is preserved in DALK surgery, the risk of tissue rejection is quite low.

DMEK (Descemet Membrane Endothelial Keratoplasty)

In the DMEK method, only the innermost layer of the cornea is replaced. This technique is an advanced surgical method performed with a very thin tissue.

It is generally applied in diseases such as:

• Corneal edema
• Endothelial failure
• Fuchs’ dystrophy After DMEK surgery, vision generally recovers faster, and the cornea’s natural structure is largely preserved.

DSAEK (Descemet Stripping Automated Endothelial Keratoplasty)

DSAEK is also a technique in which the inner layer of the cornea is replaced. A slightly thicker tissue is used compared to DMEK, and it may be surgically more suitable for some patients.

This method is one of the frequently preferred techniques in:

• Endothelial diseases
• Corneal edema

How Is the Appropriate Method Determined?

The most important issue in corneal transplantation is accurately determining which layer of the cornea is affected by the disease. For this, a detailed eye examination, corneal mapping, and advanced tests are performed.

Today, whenever possible, layered transplants in which only the damaged layer is replaced are preferred. However, in some patients, the most suitable method may be full-thickness corneal transplantation. Therefore, the treatment plan is determined individually for each patient.

How Is Corneal Transplantation Surgery Performed?

Corneal transplantation surgery (keratoplasty) is the procedure of removing damaged corneal tissue and replacing it with healthy donor corneal tissue. The surgery is an eye procedure requiring care and experience, performed using advanced microscopes and precise surgical techniques.

The surgical process generally consists of several stages.

Preoperative Preparation

Patients scheduled for corneal transplantation first undergo a detailed eye examination. At this stage:

• Corneal thickness is measured
• Corneal mapping is performed
• Intraocular pressure is evaluated
• The back layers of the eye are examined These tests help determine which layer of the cornea is affected by the disease and allow the transplantation method to be planned.

Surgical Process

Corneal transplantation surgery is generally performed under local anesthesia. This ensures the patient feels no pain and remains comfortable during the surgery. In certain special cases, general anesthesia may also be preferred.

During the surgery:

• The damaged corneal tissue is carefully removed.
• Healthy corneal tissue obtained from a donor is placed in the position of the patient’s cornea.
• The new cornea is secured with very fine, specialized stitches. In layered transplants, only the diseased layer is replaced, and healthy tissue is preserved. In these methods, the surgery is performed on more delicate layers.

The duration of the surgery varies depending on the method applied, but it is generally completed in 30 to 90 minutes.

The First Hours After Surgery

After the surgery, the eye is covered with a protective dressing, and the patient can generally be discharged the same day. In the first days:

• Mild stinging may occur
• Light sensitivity may be observed
• The drops prescribed by the doctor should be used regularly This process is quite important for the healthy progress of healing.

Postoperative Healing Process

The healing period after corneal transplantation may vary depending on the type of surgery performed. Healing is generally faster with layered transplants, while vision may take longer to clear with full-thickness transplants.

During the healing process:

• Regular doctor check-ups are performed
• Eye drops are used
• Protecting the eye from impact is important Stitches can generally remain in place for a long time and are removed when the doctor deems it necessary.

Corneal transplantation surgery, when performed with proper patient selection and appropriate surgical techniques, is an effective treatment method that can provide a marked increase in visual quality. The success of the surgery depends both on the surgical technique and on regular postoperative care.

Preparation Process Before Corneal Transplantation

The preoperative preparation process is of great importance for the success of corneal transplantation surgery. During this process, the patient’s eye structure is evaluated in detail, the stage of the disease is determined, and the surgical technique to be applied is planned. The goal is to ensure that the surgery is performed as safely and accurately as possible.

Detailed Eye Examination

Patients scheduled for corneal transplantation first undergo a comprehensive eye examination. In this examination:

• Vision level is measured
• Corneal structure and transparency are evaluated
• Intraocular pressure is measured
• The back layer of the eye (retina and nerve layer) is examined This evaluation is important for understanding whether vision loss originates solely from the cornea.

Corneal Tests and Measurements

Certain special tests are performed before corneal transplantation. These include:

• Corneal topography (corneal mapping)
• Corneal thickness measurement
• Endothelial cell count (when necessary) These measurements help determine which layer of the cornea is affected and allow the most suitable transplantation method to be selected.

General Health Assessment

As with any surgical procedure, the patient’s general health status is reviewed before corneal transplantation. Medications used, chronic diseases, and previous surgeries are evaluated. Additional tests may be requested when necessary.

What Patients Should Pay Attention to Before Surgery

Patients are given certain recommendations before surgery:

• The drops recommended by the doctor should be used regularly
• Makeup should not be worn on the day of surgery
• The area around the eye should be kept clean
• The fasting period recommended by the doctor should be followed (when necessary) Following these rules helps ensure the surgery proceeds safely and without complications.

Surgical Planning

Once all examinations and tests are completed, the day of surgery is planned. The technique to be used is determined based on the type of disease and the condition of the cornea. Today, thanks to advanced surgical methods, a personalized treatment plan can be created for many patients.

The preoperative preparation process for corneal transplantation is an important stage that directly affects the success of the surgery. Therefore, it is of great importance for patients not to neglect the examination and check-up process and to follow the doctor’s recommendations.