Improving Global Access To Sight-Saving Corneal Surgery

Corneal transplantation is among the greatest achievements in ophthalmology, one that restores vision to thousands of patients each year. Every successful transplant, however, depends on a remarkably fragile chain of events: a suitable donor must be identified, the tissue must be recovered and screened, the cornea must be preserved and transported, and a skilled surgeon and postoperative infrastructure must be available. Failure anywhere in that chain prevents sight restoration, and across much of the world, one or more of the links are absent.

A global survey of 2012 data estimated that approximately 12.7 million people were awaiting corneal transplantation and only one donor cornea was available for every 70 patients in need.¹ In the United States, high-quality donor tissue is generally available for elective surgery. In many low- and middle-income countries, however, where corneal blindness is most prevalent, shortages of donor tissue are compounded by limited eye bank infrastructure, insufficient surgical capacity, and inadequate patient access to long-term postoperative care. The donor shortage is not simply a problem of donation; it is also an engineering, economic, manufacturing, and health systems challenge. Donor corneas are perishable, biologically variable, and tightly regulated. Every graft must be recovered, screened, preserved, graded, transported, and transplanted within a narrow therapeutic window. Established eye banks accomplish this through specialized recovery teams, accredited laboratories, preservation technologies, transportation networks, quality assurance systems, and close partnerships with surgeons. In 2024, US eye banks distributed 85,926 corneal grafts, thereby supporting 51,559 domestic keratoplasty procedures and exporting 26,732 tissues internationally.² These accomplishments reflect decades of investment in infrastructure that many countries cannot readily replicate.

Although corneas are donated through extraordinary generosity, the tissue is far from cost-free by the time it reaches the OR. Donor identification, tissue recovery, infectious disease testing, endothelial assessment, preservation, storage, transportation, and regulatory oversight all require highly specialized personnel and facilities. A cornea that cannot be safely recovered, appropriately preserved, delivered on time, and implanted by a trained surgeon cannot restore sight.

Implementing a framework of five complementary principles could shift the objective from simply performing more corneal transplants to reducing reliance on donor tissue altogether and thereby improve patient access to corneal surgery.

Principle No. 1: Preserve the Native Cornea

The first goal should always be to preserve the patient's own cornea before transplantation becomes necessary. In carefully selected patients with central Fuchs endothelial corneal dystrophy and adequate peripheral endothelial reserve, Descemet stripping only can restore corneal clarity by allowing peripheral endothelial cells to migrate centrally, particularly when surgery is combined with topical Rho kinase inhibition.³ Although Descemet stripping only is not appropriate for advanced disease, the procedure illustrates that functional recovery may be achieved without donor tissue.

Emerging topical biologics, regenerative therapies, and gene-based treatments may further delay or avoid the need for corneal transplantation by preserving endothelial function, stimulating cellular regeneration, or correcting molecular abnormalities.⁴ Although still largely investigational, these therapies represent an important conceptual shift from replacing damaged tissue to preventing tissue loss.

Principle No. 2: Replace Only What Is Diseased

When transplantation becomes necessary, surgery should replace only the affected corneal layer. Deep anterior lamellar keratoplasty (DALK) can preserve healthy endothelium in eyes with stromal disease, whereas Descemet membrane endothelial keratoplasty selectively replaces diseased endothelium while retaining the anterior cornea.^5,6 Compared with penetrating keratoplasty, DALK and Descemet membrane endothelial keratoplasty can preserve healthy tissue, reduce immunologic rejection, accelerate visual rehabilitation, and improve structural integrity.

Layer-specific surgery also creates an opportunity to maximize tissue utilization. In certain cases, a single donor cornea can provide anterior stromal tissue for DALK in one recipient and posterior tissue for endothelial keratoplasty in another, thus allowing one donor graft to restore vision to two patients.⁷ The donor scleral rim may also provide limbal tissue for limbal stem cell transplantation, further extending the value of each donated eye.

Despite the advantages, the widespread implementation of layer-specific corneal surgery has been limited by logistic complexities in tissue allocation and the challenges of coordinating multiple recipients and surgical teams.

Principle No. 3: Maximize the Value of Every Donor

A logical extension of tissue sharing is cellular therapy. Expanded endothelial cells from a single donor may ultimately generate treatment for numerous patients. An intracameral injection of cultured human corneal endothelial cells combined with Rho kinase inhibition has already demonstrated encouraging results in eyes with bullous keratopathy.⁸ According to more recent company-reported phase 1/2 data, 65% of patients receiving the highest dose had gained at least 15 Early Treatment Diabetic Retinopathy Study (ETDRS) letters at 12 months.⁹ Peer-reviewed research and longer-term follow-up are needed.

Whether endothelial cell therapy expands global access ultimately depends less on biology than on manufacturing. Cell expansion, potency testing, cryopreservation, quality assurance, regulatory approval, distribution, and reimbursement must all become scalable and affordable before this technology has the potential to substantially reduce disparities in access.

Principle No. 4: Regenerate Rather Than Replace

Bioengineered tissues offer an opportunity to restore corneal structure without relying on human donor tissue. In eyes with advanced keratoconus, the implantation of an acellular bioengineered porcine collagen lenticule resulted in sustained corneal thickening, corneal flattening, and improved visual acuity through 24 months.¹⁰ Such biomaterials may reduce dependence on donor tissue for select stromal diseases, particularly in regions lacking mature eye-banking systems.

Principle No. 5: Eliminate Donor Dependence

The ultimate objective is to develop a fully synthetic corneal replacement that does not require human donor tissue. Current keratoprostheses have demonstrated that artificial devices can restore vision to otherwise untreatable eyes. The Boston Type I keratoprosthesis (Massachusetts Eye & Ear Infirmary) remains the benchmark, achieving a visual acuity of 20/200 or better in approximately 70% of eyes.¹¹ However, the device still requires a donor corneal carrier and necessitates lifelong surveillance for glaucoma, infection, sterile keratolysis, retroprosthetic membrane formation, and other complications.¹²

Future keratoprostheses must accomplish far more than just providing optical clarity. They must also establish a durable watertight seal with surrounding tissue, possess biomechanical properties closely approximating those of the native cornea, resist microbial colonization, and minimize inflammation and tissue wear. Ideally, future devices will feature antimicrobial surfaces, offer sustained drug delivery, incorporate biosensors capable of monitoring IOP or tissue integrity, and use manufacturing processes that enable inexpensive worldwide distribution.

Even the most sophisticated device, however, will have a limited global impact if successful implantation requires highly specialized surgeons or surgical equipment or intensive lifelong tertiary care. Accessibility depends as much on simplicity, reproducibility, and affordability as it does on technological innovation.

Looking Ahead

The future of corneal surgery is unlikely to be defined by a single breakthrough but by different technologies that serve different patients. A child with infectious corneal scarring in a rural setting, an older adult with Fuchs endothelial dystrophy in a tertiary referral center, and a patient with autoimmune ocular surface disease after multiple failed grafts require fundamentally different solutions.

The ultimate measure of progress is the number of patients who regain vision regardless of where they reside, not the number of corneal transplants performed. Moving the field forward requires coordinated advances in regenerative medicine, tissue engineering, biomaterials, cell manufacturing, eye banking, surgical training, and health care delivery. The future of keratoplasty lies in making the restoration of sight progressively less reliant on donor tissue and costly infrastructure that depend heavily on geography.