CAIRS Surgery for Keratoconus Treatment

CAIRS (Corneal Allogenic Intrastromal Ring Segments) is a modern surgical technique used in the treatment of keratoconus. Although it is classified as a surgical procedure in the medical literature, it is commonly referred to as CAIRS surgery in patient communications and everyday usage due to the nature of its application.

Keratoconus is a progressive corneal disease characterized by thinning and forward protrusion of the cornea. The resulting irregularity of the corneal surface prevents light from focusing properly on the retina, which can lead to significant visual quality problems — including blurred vision, light scattering, double vision, and difficulties with night vision.

Today, the goal of keratoconus treatment is not merely to improve vision, but also to control disease progression, strengthen the corneal structure, and delay or prevent the need for corneal transplantation wherever possible. CAIRS surgery is one of the modern surgical approaches developed to achieve these goals.

CAIRS (Corneal Allogenic Intrastromal Ring Segments) is an advanced surgical technique based on the principle of preparing the segments placed within the cornea from natural corneal tissue rather than synthetic materials. This approach aims to support the cornea's biomechanical structure in a more physiological manner and is recognized as a significant advancement in modern keratoconus surgery.

In CAIRS surgery, femtosecond laser technology is used to create micron-level precision channels within the cornea. Specially prepared natural corneal segments are then placed into these channels. Once in position, the segments help the corneal surface assume a more regular shape and may contribute to improved visual quality by allowing light to focus more accurately on the retina.

One of the most important advantages of this technique is the high biocompatibility of the material used. By utilizing natural corneal tissue, the risk of foreign body reaction is reduced, tissue tolerance is improved, and corneal mechanics can be preserved in a more natural way. These characteristics make CAIRS surgery a reliable and effective treatment option, particularly in appropriately selected patients.

CAIRS surgery may not be suitable for every patient with keratoconus. The treatment plan is determined on an individualized basis, taking into account multiple parameters including corneal thickness, disease stage, topography findings, and the patient's level of vision. For this reason, a thorough eye examination and advanced corneal analysis are critical in selecting the right treatment approach.

When applied with modern technology, careful patient selection, and experienced surgical technique, CAIRS surgery represents a robust surgical option in keratoconus treatment — one that aims to support corneal structure and improve visual quality.

What Is CAIRS Surgery?

CAIRS surgery (Corneal Allogenic Intrastromal Ring Segments) is a modern surgical procedure used in the treatment of keratoconus, designed to reinforce the corneal structure. In this technique, the segments placed within the cornea are prepared from natural human corneal tissue rather than synthetic materials. This approach aims to improve biological compatibility with the cornea and provide a more natural, physiological form of support.

In keratoconus, the cornea thins and bulges forward. This causes irregularity of the corneal surface and prevents light from focusing correctly on the retina. The primary goal of CAIRS surgery is to use the implanted segments to reshape the cornea into a more regular form and thereby improve visual quality.

Advantages of CAIRS Surgery and Why It Is Chosen

CAIRS surgery is a modern approach that supports corneal structure in a more natural way during keratoconus treatment. The use of segments derived from natural corneal tissue enhances biological compatibility and improves tissue tolerance.

Key advantages include:

• High biocompatibility through the use of natural tissue

• Helps regularize the shape of the cornea

• Can improve visual quality

• May delay progression toward corneal transplantation

• Precise and safe application using femtosecond laser

In suitable patients, CAIRS surgery is regarded as an effective treatment option that supports corneal structure and aims to enhance visual quality.

The Fundamental Principle of the CAIRS Technique

The working principle of CAIRS relies on segments placed within the corneal stroma that mechanically support corneal curvature. What distinguishes this technique from conventional ring treatments, however, is that the material used is of biological origin.

Segments derived from natural corneal tissue:

• Achieve greater compatibility with the cornea

• Offer improved tissue tolerance

• Reduce the risk of foreign body reaction

• Support corneal biomechanics in a more physiological manner

These properties have established CAIRS surgery as an important advancement in modern keratoconus surgery.

How Did CAIRS Come About?

Intrastromal ring segments have been used in keratoconus treatment for many years. In traditional approaches, these segments were manufactured from synthetic materials, and successful outcomes were achieved in a large number of patients. However, research into the use of natural tissue — with a view to improving biological compatibility and long-term tolerance — continued in parallel.

The CAIRS technique emerged from this body of research. It is based on the principle of converting natural corneal tissue into segments and implanting them within the cornea — an approach that has made it possible to provide support that is more consistent with the cornea's natural architecture.

The Goals of CAIRS Surgery

CAIRS surgery is not a procedure aimed at eliminating keratoconus entirely. Its primary objectives are:

• To regularize the shape of the cornea

• To reduce irregular astigmatism

• To improve visual quality

• To improve contact lens tolerance

• To delay or prevent the need for corneal transplantation

CAIRS surgery is therefore considered a procedure that strengthens the corneal structure in keratoconus treatment and aims to reduce the impact of the disease on vision.

What Technology Is Used in CAIRS Surgery?

One of the most critical steps in CAIRS surgery is creating the channels within the cornea where the segments will be placed. This is performed using femtosecond laser technology.

The femtosecond laser:

• Provides micron-level precision

• Causes minimal trauma to the tissue

• Enhances surgical safety

• Supports the healing process

This advanced technology allows the segments to be placed within the cornea with exceptional precision.

The Significance of CAIRS Surgery

CAIRS surgery is one of the notable examples of biological tissue use in keratoconus surgery. The use of natural corneal tissue may contribute to more stable and physiological outcomes by improving compatibility between the cornea and the implanted segments.

In appropriately selected patients, CAIRS surgery is now recognized among the reliable surgical options that support corneal structure and aim to improve visual quality.

How Is CAIRS Surgery Performed?

CAIRS surgery is a procedure that requires advanced technology and meticulous surgical planning. The most important factors determining its success are proper patient selection, detailed corneal analysis, and experienced surgical execution.

The surgical process generally consists of several stages, each planned with care.

Pre-Operative Assessment

Before CAIRS surgery, the structure of the eye is examined in detail. This evaluation process is critical in determining whether the treatment is appropriate.

The pre-operative workup typically includes:

• Corneal topography and tomography

• Corneal thickness measurement (pachymetry)

• Visual acuity assessment

• Ocular surface and retinal examination

These analyses allow the stage of keratoconus, the weakest area of the cornea, and the intended locations for segment placement to be identified.

The treatment plan is prepared on an individualized basis for each patient.

The Femtosecond Laser Stage

One of the most important steps in CAIRS surgery is the creation of the channels within the cornea where the segments will be placed.

This is performed using femtosecond laser technology — an advanced laser system capable of creating highly controlled incisions within the corneal tissue with micron-level precision.

At this stage:

• Tunnels for the segments are created within the cornea

• The procedure is guided by computer-assisted planning

• Minimal trauma is applied to the corneal tissue

The use of femtosecond laser significantly enhances the safety and precision of the procedure.

Placement of the Natural Corneal Segments

Once the channels have been prepared, segments derived from natural corneal tissue are placed into them.

These segments: