If you've been living with keratoconus for a while, you probably know the standard progression. Glasses first, then soft contacts, then specialty lenses that get harder to fit and tolerate as the cornea continues to change. For many patients, cross-linking slows things down, and Intacs can help reshape the cornea enough to buy more time with contact lenses. But for patients with moderate to advanced disease, there's often a point where the options start to feel limited, and a corneal transplant gets mentioned as the next step.
That conversation is starting to change. A procedure called Corneal Tissue Addition Keratoplasty, or CTAK, has emerged as a promising alternative for patients who aren't ready for a transplant and haven't gotten enough from existing treatments. It won't be right for everyone, but for the right patients it's producing results that weren't possible a few years ago. At Clearview, we're following its development closely, and we want our patients to understand what it is and where it fits in the treatment landscape.
CTAK is a surgical procedure that rebuilds the cornea from within, without replacing it. The basic concept is straightforward: a thin piece of donor corneal tissue is cut to precise, custom dimensions using a femtosecond laser, then placed inside a channel created in the patient's own corneal stroma. The inlay sits behind the pupil area, filling out the thinned, irregular tissue that keratoconus has left behind.
The key word is custom. Every CTAK inlay is designed specifically for the patient's corneal topography and tomography. The thickness, arc length, and curvature of the tissue are all adjusted based on a detailed map of the individual's cornea, with the goal of restoring as normal a shape as possible. The tissue itself is preserved, gamma-irradiated, and sterilized donor corneal tissue, processed by a company called CorneaGen using the Ziemer Z8 femtosecond laser.
The procedure was developed by Dr. Peter Hersh and his colleagues at the Cornea and Laser Eye Institute in New Jersey, growing out of earlier work with intrastromal tissue inlays that began around 2015. It has since been refined into a pupil-sparing technique that avoids the visual quality issues that earlier versions of the concept ran into.
This is a fair question, because keratoconus patients often encounter a lot of terminology, Intacs, cross-linking, CAIRS, transplants, and it can be hard to keep straight.
Intacs are synthetic ring segments implanted in the corneal periphery to flatten and regularize the cone. They work well in certain cases but don't add tissue to the cornea and can't address severe irregularity or significant thinning.
CAIRS (Corneal Allogenic Intrastromal Ring Segments) are a newer version of that concept using donor corneal tissue instead of synthetic material, offering better biocompatibility. But CAIRS is still ring-based and is designed to mimic the effect of Intacs, not to reconstitute the corneal shape more broadly.
CTAK is different because it's a form of lamellar keratoplasty, meaning it's actually adding structured, shaped tissue to the cornea. It's not a ring; it's a custom-formed inlay that addresses the specific shape abnormality of that individual eye. Think of it as filling in what keratoconus has thinned out, using tissue that's been cut to match what that area should look like.
Full corneal transplants, whether DALK or penetrating keratoplasty, replace the cornea entirely. They can be effective but carry longer recovery times, higher risk profiles, and a lifelong dependence on a successful graft. CTAK leaves the patient's own cornea intact and in place.
The published data is early but encouraging. In the prospective clinical trial that supported CTAK's commercial launch, 21 eyes of 18 patients were treated and followed over time. The results showed:
These are meaningful numbers for a patient population that often has very limited improvement options. The corneal topography improvements are particularly significant because they suggest the procedure is changing the structural problem, not just masking it.
CTAK has been featured on the cover of the Journal of Cataract and Refractive Surgery, and it has received attention from the American Academy of Ophthalmology as a procedure with real promise for the keratoconus population.
CTAK is designed for patients with keratoconus or post-LASIK ectasia who have irregular corneal shape causing reduced vision and who haven't achieved satisfactory results through other means. It tends to be most relevant for patients who:
CTAK is often discussed alongside cross-linking rather than as a replacement for it. Cross-linking stops the progression of keratoconus by strengthening the cornea's collagen structure. CTAK addresses the shape that's already been lost. The two procedures can be complementary, with cross-linking used first to stabilize the eye before CTAK is considered.
We don't currently offer CTAK at Clearview. It's a newer procedure being performed at a limited number of specialized centers, and our team is watching its development carefully. What we do offer is a comprehensive keratoconus evaluation and a full range of the established treatments that have helped keratoconus patients for years, including corneal collagen cross-linking, Intacs, and scleral lens fitting guidance.
For patients who are in the earlier stages of keratoconus, early intervention with cross-linking remains the most important thing you can do to protect your vision long term. For patients further along who are exploring what comes next, we want to be a resource for that conversation, even when the answer involves understanding options beyond what we currently provide.
If you have keratoconus and haven't had a comprehensive evaluation recently, or if you've been told your options are running out, come in and talk to Dr. Feldman. The field is moving faster than it used to, and it's worth making sure you have a complete picture of what's available before making any major decisions.
