Innovative solutions are paving the way for more accessible and effective corneal treatments
Imagine a world where the waiting list for donor corneal tissue isn’t a looming number that haunts millions. Thanks to recent innovations, that reality might not be as far off as it once seemed. Here’s a glimpse into the exciting future that could reshape cornea transplantation forever.
As Dr. Marjan Farid, director of Cornea, Cataract and Refractive Surgery at the University of California-Irvine (USA) Gavin Herbert Eye Institute, explained, “Corneal transplantation has come a long way over the past couple of decades.” The field has made great strides from penetrating keratoplasty—the full-thickness replacement of the cornea—toward more refined approaches. “Now, with the evolution of lamellar keratoplasty, we can transplant only the diseased part,” she added, referring to modern techniques like Descemet stripping endothelial keratoplasty (DSEK), Descemet membrane endothelial keratoplasty (DMEK), and deep anterior lamellar keratoplasty (DALK).
Yet even with these advancements, a critical challenge remains: A global shortage of donor tissue. With an estimated 12.7 million people waiting for a transplant, the demand far outweighs the supply. This reality has driven the exploration of novel transplantation methods— approaches that could alleviate the shortage and provide sustainable, scalable alternatives.1
Artificial corneas and bioengineered grafts
Artificial corneal transplantation is not a new feat. Dr. Claes Dohlman (Sweden) first introduced Boston keratoprosthesis (KPro) back in 1965. “It underwent multiple iterations and evolution to the current version we have today,” explained Dr. Farid. “But it carries with it a lot of risk including progression of glaucoma, infections, and corneal melts.”
One promising development in artificial corneas is EndoArt® (EyeYon Medical; Ness Ziona, Israel), a 50-micron thick artificial endothelial prosthesis designed to block the influx of aqueous fluid from the anterior chamber. This flexible, easyto-store implant offers an alternative to traditional donor corneas. “This is working in higher-risk transplants,” reported Dr. Farid. “It has received approval in certain countries for highrisk eyes, and we’re looking forward to seeing it go into trials here in the US as well.”2
Another breakthrough is the CorNeat KPro (CorNeat Vision; Ra’anana, Israel), a synthetic cornea that bonds directly to the conjunctiva, eliminating the need for vascularized corneal tissue. It combines a polymethyl methacrylate (PMMA) optical core with an external biointegrating skirt, designed to support long-term stability and integration. While clinical trials are still ongoing, Dr. Farid pointed out that, “They’ve had some human surgeries, and while some have failed, others have succeeded. We’re watching closely to see how it evolves.”3
On the horizon, there’s also work being done on bioengineered tissues. One particularly exciting development comes from Rafat et al., who conducted a clinical trial using double-crosslinked bioengineered porcine constructs (BPCDX) in patients with keratoconus. Implanted during a femtosecond laser-enabled intrastromal keratoplasty procedure, the BPCDX grafts led to significant improvements in visual acuity and a reduction in keratometry readings for the majority of the patients, with no cases of inflammation or rejection at 24 months.4
Natural corneal rings
Traditionally, intrastromal corneal ring segments (ICRSs), made of PMMA, have long been used to treat keratoconus, but complications like extrusion pose ongoing challenges. Building on ICRSs, corneal allogenic intrastromal ring segments (CAIRS), and corneal tissue addition keratoplasty (CTAK) reduced the risk of extrusion, but both require transplant-grade donor corneal tissue.
That’s where KeraNatural® (VisionGift; Boston, USA) steps in. These rings are derived from donor corneas deemed unsuitable for full transplants and boast a shelf life of two years, making them a practical option for surgeons and patients alike.5
Regenerative medicine and cell therapy
A new frontier in corneal decompensation is Descemet stripping only (DSO), where surgeons peel off the damaged Descemet membrane and rely on the patient’s own cells to regenerate.
“This works in eyes where the peripheral endothelial corneal cells are healthy,” explained Dr. Farid. “The thought is that those will migrate to the center, where we remove the diseased cells and repopulate in the central cornea.”
To enhance this process, rho-kinase inhibitors are utilized to promote faster corneal clearing. With clinical trial success rates reaching 90%, DSO offers significant promise for patients suffering from Fuchs endothelial corneal dystrophy (FECD).6
In addition to DSO, the development of cultured corneal endothelial cells (CECs) marks another groundbreaking advancement in corneal therapy. In a landmark study, researchers injected CECs derived from donor corneas into the eyes of patients with corneal decompensation. “I think cultured cells are the future for endothelial disease,” Dr. Farid predicted.7
These cells are cultured in the lab and injected into the anterior chamber, where they adhere to the back of the cornea and help to restore transparency. The results from trials were impressive, with significant improvements in vision and corneal thickness, and long-term follow-up studies have continued to show positive outcomes. “It amazingly clears the cornea, and it heals the endothelial disease,” remarked Dr. Farid. “These patients have almost very little to no risk of rejection.”7
A key advantage of CECs is their scalability; a single donor cornea can produce enough cultured cells to treat multiple patients. Japan has already embraced this innovation by approving a corneal cell therapy called Vyznova® (Aurion Biotech; Seattle, USA), with additional therapies currently undergoing trials worldwide.8
The challenges ahead
The novel approaches to corneal transplantation represent a seismic shift in how we treat corneal diseases. Yet, with innovation comes challenges.
“Expense is currently the top concern for both surgeons and patients,” Dr. Farid noted. The high costs and technical complexity associated with these cutting-edge procedures may be prohibitive, especially in low-resource settings. And, while early data is promising, long-term outcomes for many of these techniques are still under investigation, leaving open questions about their sustainability and effectiveness over time.
Despite these hurdles, the future is undeniably bright. As techniques become more refined, costs could decrease and training could become more widespread, ensuring that more patients around the world can benefit from these life-changing procedures. At the end of the day, the potential for more effective, accessible, and widely available corneal transplant options is not just a hope—it’s an expectation.
References
- Gain P, Jullienne R, He Z, et al. Global survey of corneal transplantation and eye banking. JAMA Ophthalmol. 2016;134(2):167-73.
- Auffarth GU, Son HS, Koch M, et al. Implantation of an artificial endothelial layer for treatment of chronic corneal edema. Cornea. 2021;40(12):1633-1638.
- Litvin G, Klein I, Litvin Y, et al. CorNeat Kpro: Ocular implantation study in rabbits. Cornea. 2021;40(9):1165-1174.
- Rafat M, Jabbarvand M, Sharma N, Xeroudaki M, et al. Bioengineered corneal tissue for minimally invasive vision restoration in advanced keratoconus in two clinical cohorts. Nat Biotechnol. 2023;41(1):70-81.
- Kramer EG, Boshnick EL. Scleral lenses in the treatment of post-LASIK ectasia and superficial neovascularization of intrastromal corneal ring segments. Cont Lens Anterior Eye. 2015;38(4):298303.
- Colby K. Descemet stripping only for Fuchs endothelial corneal dystrophy: Will it become the gold standard? Cornea. 2022;41(3):269-271.
- Kinoshita S, Koizumi N, Ueno M, et al. Injection of cultured cells with a ROCK inhibitor for bullous keratopathy. N Engl J Med. 2018;378:995-1003.
- Ong HS, Ang M, Mehta JS. Evolution of therapies for the corneal endothelium: Past, present and future approaches. Br J Ophthalmol. 2021;105(4):454-467.
Editor’s Note: A version of this article was first published in CAKE Magazine Issue 24.
