Once donor tissue enters the transplantation pathway, preservation, allocation, logistics, surgical capacity, and recipient readiness all determine whether it ultimately reaches a patient in need. The scale of the unmet need is enormous. Globally, an estimated 12.7 million individuals are waiting for a corneal transplant, with only one donor cornea available for every 70 patients in need.

Yet the authors emphasize a crucial distinction that is often overlooked in discussions of the shortage: the number of corneas recovered should not be equated with the number actually available for transplantation. Recovered tissue may subsequently be excluded because it fails to meet clinical or safety criteria, including inadequate endothelial quality or findings identified during donor screening and microbiological or serological evaluation. Tissue may also be directed to research or training rather than clinical use.

Consequently, recovery-to-transplantation ratios alone cannot quantify avoidable tissue non-utilization, and a more informative assessment requires distinguishing appropriate exclusion from the failure to transplant tissue that had already been deemed suitable for clinical use. This distinction matters because some non-utilization is unavoidable and appropriate, reflecting donor eligibility, tissue quality, or microbiological and serological findings. In other circumstances, however, potentially transplantable tissue may never reach a recipient because of logistical constraints, limited preservation time, case cancellation, or difficulties in timely reallocation.

The challenge, as the authors frame it, is not only whether tissue exists, but whether it reaches the right patient, in the right form, at the right time. What ultimately matters is how effectively recovered tissue is preserved, allocated, repurposed when appropriate, and translated into clinical use. That perspective shifts the conversation from donor recruitment alone toward the resilience and efficiency of the entire eye-banking and surgical system.

Centers that depend heavily on imported tissue are especially exposed to these pressures, and the experience of the KKESH Eye Bank illustrates the point vividly. Historically, KKESH served a broader national distribution role, receiving predominantly imported corneal tissue and supplying tissue to other centers across Saudi Arabia. More recently, several centers have established their own eye bank services and obtain imported tissue directly according to their clinical needs.

The KKESH Eye Bank now primarily supports transplantation within the institution through tissue receipt, storage, allocation, and coordination with surgical services, while maintaining a smaller local procurement pathway. Its role is also evolving toward more systematic and advanced local tissue processing, a shift with significant implications for how donor corneas are used. That evolution is already visible in the operating theater.

Although Descemet stripping automated endothelial keratoplasty (DSAEK) tissue has been prepared at KKESH for more than two decades, preparation was historically performed largely in the operating room according to individual surgeon preference. In 2025, the institution initiated a transition toward systematic DSAEK tissue processing within the Eye Bank using multiple technologies. This expansion also includes the development of an accurate, cost-effective laser-based method for local preparation of corneal allogenic intrastromal ring segments (CAIRS), with potential application to patch graft preparation.

Femtosecond-laser technology is currently being implemented to further expand local processing capabilities, including CAIRS preparation, Bowman membrane transplantation, and DSAEK tissue preparation. The vulnerability of import-dependent systems was demonstrated starkly during periods of major disruption. During the COVID-19 pandemic, corneal procurement and transplantation rates dropped sharply worldwide.

More recently, the regional Middle East conflict beginning in mid-February 2026 disrupted supply chains at KKESH. Closure of major regional airport hubs required alternative shipping routes and adjustments to surgical scheduling. The surgical impact was measurable and severe: in the second and third weeks of March, 100 percent of available surgical sessions were cancelled.

Recovery was gradual, with only 25 percent of sessions proceeding in the first week of April and capacity fluctuating between 48 and 67 percent of normal levels in the following weeks. Pre-processed DSAEK and Descemet membrane endothelial keratoplasty (DMEK) grafts were particularly vulnerable because their procedure-specific preparation limited opportunities for reallocation. In response, the team reduced pre-cut tissue orders, adjusted processing and surgical timing to anticipated delivery, and gave priority to patients who could reach the hospital at short notice.

This experience shows how quickly disruption in international transport can translate into reduced access to transplantation, even when donor tissue remains available elsewhere. It also highlights a structural tension in modern corneal surgery: procedure-specific tissue preparation, while clinically valuable, reduces flexibility when the intended transplantation cannot proceed as scheduled because of patient-related, clinical, or logistical factors. In such circumstances, successful reallocation depends on identifying another suitable recipient within the remaining preservation window.

At KKESH, patient scheduling and confirmation are primarily managed by the clinical services, whereas the Eye Bank coordinates tissue availability, allocation, and preparation with the surgical schedule. When transplantation cannot proceed as planned, the Eye Bank works with the clinical team to identify and contact suitable alternative recipients who can attend within the remaining preservation period, and when feasible, surgery may be arranged outside the surgeon's originally allocated operating schedule, provided both patient and surgeon agree to proceed. Preservation strategy itself shapes this flexibility.

Hypothermic storage, commonly used in the United States and for imported tissue received at KKESH, provides a relatively simple preservation pathway but a limited storage window, generally approximately 7 to 14 days. This shorter interval requires close coordination among tissue delivery, recipient readiness, surgeon availability, and operating room access, and delays or cancellations occurring late in the preservation period leave less time for successful reallocation. Organ culture, widely used by European eye banks, permits storage for approximately four weeks or more and allows microbiological surveillance before tissue release.

This longer preservation window can facilitate tissue allocation, recipient selection, surgical scheduling, and reallocation when an intended procedure cannot proceed. Its principal advantage from a utilization perspective is therefore greater logistical flexibility rather than an increase in the underlying donor supply, though organ culture demands dedicated infrastructure, controlled incubation and monitoring, microbiological testing, and additional tissue-handling procedures before transplantation. Glycerol-preserved and similarly processed tissues further expand the potential use of tissue that might otherwise expire, particularly in emergency and tectonic settings where optical clarity is not the primary concern, providing additional flexibility during periods of system stress without fully replacing fresh tissue for optical keratoplasty.

Perhaps the most transformative idea in the article is the reconceptualization of the donor cornea itself. Historically, penetrating keratoplasty meant one donor for one recipient. Modern lamellar techniques have shattered that model: only the posterior layers are needed for endothelial keratoplasty, while anterior techniques leave posterior tissue untouched.

A donor cornea can therefore be viewed as a collection of functional components rather than as a single graft. Studies have shown that multiple stromal lenticules can be prepared from a single donor cornea, meaning one donation can help several patients. Lenticules obtained during small-incision lenticule extraction (SMILE) procedures, once routinely discarded, are being explored for therapeutic applications including inlay and overlay additive keratoplasty and other ocular surface applications.

The uses of corneal tissue extend well beyond optical keratoplasty: in glaucoma surgery, gamma-irradiated corneal tissue can be used for patch grafting over drainage devices, and in some cases a single donor cornea can serve two patients, with the endothelial component used for keratoplasty and the remaining tissue as a glaucoma patch graft. Even Descemet membrane harvested from corneas unsuitable for keratoplasty due to low endothelial cell counts or anterior stromal pathology has been used as an epiretinal graft in patients with refractory full-thickness macular holes, with encouraging rates of anatomical closure and visual recovery. The authors also point to tissue stewardship in a broader sense, including reducing the need for transplantation when effective alternatives exist.

In keratoconus, earlier diagnosis and interventions that preserve or rehabilitate the native cornea may delay or avoid keratoplasty in appropriately selected patients, reserving donor tissue for eyes in which transplantation remains necessary. Looking ahead, biosynthetic implants, xenograft platforms, and gene-edited bioengineered corneas have shown promise and may eventually reduce reliance on human donors for selected indications, though these technologies remain investigational. More efficient use of available tissue does not diminish the importance of expanding the donor pool; in import-dependent centers such as KKESH, strengthening local corneal procurement remains a strategic priority that would improve resilience during supply-chain disruptions.

If corneal shortage is partly a problem of access and utilization, the authors argue, the metrics used to evaluate eye-banking performance should evolve as well, incorporating transplantation rates, appropriate versus potentially avoidable non-utilization, successful tissue reallocation, and use of different donor cornea components. Practical measures such as coordinated patient readiness, backup-recipient pathways, flexible operating room access for time-sensitive grafts, and redistribution between eye banks could further improve utilization. The global corneal shortage, the article concludes, will not be solved by increasing donation alone; it will require eye-banking and transplantation systems that evolve alongside surgical innovation, preserving tissue longer, using each donor cornea more effectively, anticipating disruptions, and reducing potentially avoidable non-utilization to expand access without relying solely on donor recruitment.

Subject of Research: Tissue utilization, preservation, and system resilience in corneal transplantation

Article Title: Beyond donor shortage: tissue utilization and resilience in modern corneal transplantation

Article References: Algouf, I. A., Daghriri, H. A., Almutlak, M., Fairaq, R., & Bin Helayel, H. (2026). Beyond donor shortage: tissue utilization and resilience in modern corneal transplantation. Frontiers in Medicine, 13, Article 1971505. https://doi.org/10.3389/fmed.2026.1971505

Image Credits: AI Generated

DOI: 10.3389/fmed.2026.1971505

Keywords: corneal transplantation, eye banking, donor tissue utilization, lamellar keratoplasty, DSAEK, DMEK, organ culture, hypothermic storage, tissue reallocation, keratoconus, supply chain disruption, biosynthetic corneas