What Is Intracorneal ring segment (ICRS) Eye Surgery?

Intracorneal ring segment (ICRS) implantation, when performed using the latest Ziemer FEMTO LDV Z8 femtosecond laser, represents one of the most precise and patient‑friendly options for managing irregular corneas such as keratoconus and post‑refractive ectasia. Below is a detailed, clinic‑ready blog you can adapt for your ophthalmology practice website.

What are intracorneal ring segments (ICRS)?

Intracorneal ring segments (ICRS), also known as corneal ring segments or “INTACS‑style” implants, are thin, arc‑shaped medical devices made of biocompatible plastic (typically PMMA or similar polymers) that are inserted into the mid‑peripheral corneal stroma.

Their purpose is to reshape the cornea by flattening its central curvature, thereby reducing irregular astigmatism and improving the patient’s functional vision without removing any corneal tissue.

ICRS are most commonly used in:

• Mild to moderate keratoconus

• Pellucid marginal degeneration

• Post‑refractive ectasia (e.g., after LASIK or PRK)

• Selected cases of high astigmatism where contact lenses or glasses are poorly tolerated

  
  

They are often combined with corneal collagen cross‑linking (CXL) to both stabilize the cornea and improve visual outcomes.

The Ziemer FEMTO LDV Z8: A next‑generation platform

The Ziemer FEMTO LDV Z8 is a compact, all‑in‑one femtosecond laser platform designed for refractive, therapeutic, and cataract surgery, including intracorneal ring segment channel creation. It uses low‑energy femtosecond pulses in the nanojoule range, enabling highly precise, minimally disruptive tissue dissection with reduced collateral damage.

Key technological features of the Z8 include:

• High repetition rate (MHz range): Allows fast, efficient channel or pocket creation, shortening procedure time and improving patient comfort.

  
  

• Spectral‑domain OCT integration: Provides real‑time, high‑resolution cross‑sectional imaging of the cornea and anterior segment, enabling depth‑controlled, anatomy‑guided cuts and live visualization of the surgical plane.

  
  

• Tissue‑adapted pulse management: Automatically adjusts laser power depending on the tissue (e.g., lower energy for the cornea, higher for lens fragmentation), improving safety and predictability.

  
  

• Large‑tunnel and ICRS‑specific modules: The Z8’s Large Tunnel Module allows surgeons to create wider, customized tunnels that match the patient’s corneal anatomy, facilitating smoother ICRS implantation and easier removal or exchange if needed.
  

For ICRS, the Z8 is approved for “Intracorneal Rings (ICR)” procedures, meaning it is specifically cleared to create the stromal channels into which the ring segments are placed.

How ICRS with the Z8 Ziemer laser works

The procedure using the Ziemer FEMTO LDV Z8 typically follows these steps:

1. Preoperative assessment:

   
   

   • Comprehensive topography and tomography (e.g., Scheimpflug, Placido‑based systems) to map corneal shape, thickness, and irregularity.

   • Pachymetry to select the safest depth and arc length for the segments.

   • Evaluation of corneal stability, visual acuity, and suitability for combined CXL.

     
     

2. Laser channel creation:

   
   

   • The patient is positioned under the FEMTO LDV Z8, stabilized with a small applanation interface.

   • Integrated OCT guides the surgeon in setting the exact depth, arc length, and tunnel position around the cornea, avoiding the central optical zone.

   • The femtosecond laser creates a precise, smooth stromal tunnel at the planned depth, typically 60–80% of central corneal thickness, with minimal disruption to the surface epithelium.

     
     

3. Segment implantation:

   
   

   • After the laser‑created channel is completed, the surgeon gently inserts the ICRS segments into the tunnel using specialized instruments.

   • Segments can be inserted symmetrically or asymmetrically depending on the corneal irregularity, allowing customized reshaping.

     
     

4. Postoperative care:

   
   

   • Patients are usually prescribed topical steroids and antibiotics for a short period.

   • Follow‑up visits are scheduled over weeks to months to monitor corneal stability, topography, and visual function.

     
     

The Z8’s speed and image guidance typically result in a very short laser‑on time and a streamlined workflow, which many practices highlight as a benefit for both surgeon and patient.

When should ICRS be considered?

ICRS are not for every patient, but they are particularly valuable in the following clinical scenarios:

• Progressive or non‑progressive keratoconus:

  
  

  • Especially when rigid contact lenses are uncomfortable or poorly tolerated, or when there is contact lens intolerance.

  • Often combined with CXL to stabilize the cornea and improve visual and topographic outcomes.

    
    

• Post‑refractive ectasia:

  • After LASIK, PRK, or other surface procedures where the cornea has become irregular or unstable.

    
    

• High irregular astigmatism limiting functional vision:

  • When glasses or soft contact lenses no longer provide adequate quality of vision.

    
    

• Bridge to other procedures:

  • In some cases, ICRS can make the cornea more regular and suitable for later contact lens fitting, phakic IOL implantation, or even corneal transplantation if disease progresses.

    
    

Contraindications include advanced corneal thinning, severe central scarring, corneal hydrops, and very advanced disease where a corneal transplant may be the preferred option.

Benefits of ICRS with the Z8 platform

Clinical and patient‑experience benefits:

• Customized, anatomy‑guided treatment : The Z8’s OCT‑guided planning allows channels to be tailored to the patient’s corneal thickness and shape, improving safety and accuracy.

  
  

• Minimally invasive and reversible : ICRS reshape the cornea without removing tissue, and the segments can be removed or exchanged if needed, making it a relatively conservative option.

  
  

• Improved visual quality : Studies and case series show improvements in uncorrected and corrected distance visual acuity (UDVA/CDVA), reduction in maximum keratometry values, and better regularity of astigmatism after ICRS implantation.

  
  

• Faster procedures and enhanced comfort : The Z8’s high‑speed laser and low‑energy pulses reduce procedure time and intraoperative discomfort, while the “Whisper Mode”‑type airflow systems further soften the sound and environment in the operating room.

  
  

• Integration with other procedures : The Z8 can also perform Z‑LASIK, intrastromal pockets, keratoplasty cuts, and cataract‑related steps, allowing clinics to standardize workflows across multiple indications. How the Z8 laser improves ICRS compared with older techniques
  

  For many years, intracorneal ring segments (ICRS) were placed using manually created tunnels in the cornea, which relied heavily on the surgeon’s skill and experience. While effective, this mechanical technique can sometimes lead to uneven tunnel depth, irregularity, or small corneal defects, which may affect healing and comfort.
  

  At our practice, we use the Ziemer FEMTO LDV Z8 femtosecond laser to create the channels for ICRS. This laser uses high‑resolution imaging and computer‑guided planning to place the tunnel at a precise depth and arc length, tailored to your corneal shape. The result is:
  

  • Smoother, more predictable channels

  • Fewer intraoperative complications

  • Faster visual recovery and less postoperative discomfort
    

  Studies show that final vision after one year is similar between mechanical and laser‑created tunnels, but the laser approach offers better consistency and safety. By using the Z8 platform, we combine the proven benefits of ICRS with modern precision and a more comfortable experience for our patients.

  
  
  
  

Risks and potential complications

As with any surgical procedure, ICRS carries some risks, even when performed with advanced femtosecond platforms such as the Z8.

Common or less serious issues may include:

• Temporary visual disturbances (halos, glare, or night‑vision changes).

• Mild corneal haze or dry‑eye symptoms that usually resolve over weeks to months.

• Minor segment displacement or decentration that can often be managed with observation or repositioning.

  
  

More significant, though less frequent, complications include:

• Segment extrusion or migration : The ring may partially come out or move, requiring repositioning or removal.

  
  

• Corneal infection or inflammation : Rare but serious; minimized by strict aseptic technique and postoperative drops.

  
  

• Induced or worsening astigmatism or irregularity : If the segments are not optimally placed or if the cornea is unstable.

  
  

• Over‑ or under‑correction : Occasional need for enhancement, segment exchange, or additional procedures (e.g., contact lenses, CXL, or transplantation).

  
  

The Z8’s precise channel architecture and real‑time imaging help reduce some of these risks by improving depth control and minimizing unintended tissue disruption.

Why use the Z8 Ziemer for ICRS at our practice?

Highlighting your specific technology investment can reassure and educate patients:

• Swiss‑engineered precision: The Z8 platform is engineered for high‑speed, low‑energy cutting with excellent corneal smoothness and reproducible results.

  
  

• Image‑guided and customizable: OCT‑based planning allows us to design ICRS channels that match the unique anatomy of your cornea, enhancing both safety and visual outcomes.

  
  

• Part of a comprehensive corneal‑rehabilitation strategy: We often combine ICRS with corneal cross‑linking and careful contact‑lens fitting to stabilize keratoconus and improve long‑term visual rehabilitation.

For suitable patients, ICRS with the Ziemer FEMTO LDV Z8 offers a modern, minimally invasive way to reshape the cornea, improve vision, and potentially delay or avoid a corneal transplant—while preserving reversibility and flexibility in future treatment options.