Manual or femtosecond laser channel dissection: Which is better for CAIRS implantation?

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May 19, 2025

4 min read

Click here to read the Cover Story, “Experts explore CAIRS through landmarks that shaped its evolution.”

Manual dissection is inexpensive, fast and easy

We did not have a femtosecond laser in our practice, so we started implanting CAIRS manually, and it has been so successful that we have not been motivated to switch.

Manual corneal allogenic intrastromal ring segment (CAIRS) implantation is inexpensive and easy to get started with. The equipment you need is simple, and you can buy it all for a couple of thousand dollars at the most. It is nothing like the huge investment in a laser, which costs hundreds of thousands of dollars. If you are not already a high-volume laser refractive surgeon, the barrier to entry is low.

An advantage of manual implantation is that the process of creating the channels is super quick. There is a little bit of a technique required, but it is not a demanding process, and the learning curve is relatively short. Once you have gained some experience, the entire procedure becomes easy, fast and efficient.

The femtosecond laser involves moving the patient from one room to another, programming the software, and setting up and docking the laser, and all this is time-consuming. In terms of just pure speed, the manual method is much faster. The whole surgery is 3.5 minutes and takes place in one location, whereas using the femtosecond laser means shuffling back and forth from room to room and device to device. Manual implantation is a lot more efficient. Another advantage of manual vs. laser implantation is that there is a click fee with the laser. For most laser platforms, it is about $1,000 per application, and somebody has to pay for that; either patients have to pay more, or surgeons have to be reimbursed less for the procedure because they are paying to run the laser. So, using a manual technique is faster and more profitable overall.

Jack S. Parker

However, if you already have a femtosecond laser in your facility and you are familiar with it, it makes sense to start with the femtosecond laser because there is no skill required. The laser does everything in terms of making the channels, and you just take the segments and put them in. So, I am not arguing that nobody should ever use the femtosecond laser for CAIRS, but I certainly think you do not need one to get started. If you do not have one, you should not necessarily invest in one. If you do have one and you want to use it, that is also great.

The segments we use are also cut manually using the Jacob CAIRS trephine. They are shipped to us by Lions World Vision Institute and stored in albumin, which makes them shelf stable for 2 years. Albumin also imparts a pale-yellow tinge to the tissue, which allows it to be differentiated from the surrounding recipient stroma during implantation. We remove the segments from this liquid storage solution and allow them to dry on a flat surface for about 10 to 15 minutes before implantation, which stiffens and thins them, rendering them easier to implant. Soon, we should be able to receive already dried segments from our eye bank, allowing us to save time and skip the drying step.

For more information:

Jack S. Parker, MD, PhD, of Parker Cornea, Vestavia Hills, Alabama, can be reached at jack.parker@gmail.com.

Femtosecond provides comfortable, LASIK-like experience

I have been performing CAIRS surgery for the last 2 years using the Alcon WaveLight FS200 femtosecond laser, but there are several other platforms that have the same capability.

I like the femtosecond laser because it provides an easy LASIK-like experience for the patient. It is the same docking and lasering process as what we have done for many years in refractive surgery, and we know that patients have an easy, comfortable experience with just 5 mg of diazepam and a few drops of proparacaine to numb the eye. The femtosecond laser provides precision with assurance that we perform the channel at the desired depth every time and allows access to that channel through a perfectly sized self-sealing incision. Dissecting the channel is as easy and straightforward as lifting a LASIK flap, so it is familiar territory for experienced femtosecond LASIK surgeons. It is also easier to achieve the desired centering of the channel because we can visualize it directly on the screen before activating the laser. I place a centering mark on the cornea at the slit lamp before the patient lies below the laser.

Evan D. Schoenberg

I use pre-cut tissue, either VisionGift KeraNatural or CorneaGen corneal tissue addition keratoplasty (CTAK), depending upon the patient’s insurance and timing. The CorneaGen custom-cut tissue is a little more logistically challenging because it requires about 5 weeks of lead time, and the CAIRS are custom-made and not returnable or usable for other patients. If I am dealing with a case in which there is plenty of lead time, and the patient is reliable and has a proper insurance plan, I use the CTAK segments. If I have a patient whose insurance is a bit more of an unknown, and we have less experience with that payer or we may not be as confident that the patient is going to show up to surgery, then I use the precut KeraNatural tissue. If that patient is a no-show or we have other issues, we can easily use that tissue segment, which has not been opened yet, for a different patient down the line. The femtosecond technique works great with both KeraNatural and CTAK tissues. The channel parameters can be varied across a wide degree: The inner channel diameters can be anywhere from 4.5 mm to 7 mm and the outer diameter anywhere from 7.7 mm to 10.5 mm. The result is that we have more fine-tuned control over tissue placement and the optical zone of that tissue than if we had a manual blade or set of blades.

I perform surgery entirely within my LASIK suite, using the microscope of my WaveLight EX500 laser for tissue insertion. The patient experience is seamless as the bed moves from one to the other, just like with LASIK.

I agree with Dr. Parker: Both manual and femtosecond channel creation for CAIRS can provide fantastic results for our patients. For a surgeon with access to a femtosecond laser with channel creation capabilities, I think this is a natural procedure to add to their laser surgery day’s schedule.