Staying up to date on the latest developments in eye banking is crucial to surgeons providing patients with the best care. One of the many things I have learned over the years from eye banking peers is that they are always working on something new and exciting.
This article highlights some up-and-coming innovations stateside, based on conversations with friends at the Eye Banking Association of America (EBAA).
Donor-Derived Lab-Grown Cells
Many potential issues, such as donor tissue preparation complications, intraoperative tissue complications, or corneal graft rejections, can arise from the time an eye bank receives a call regarding a potential donor, until the patient gets that last postop visit and “graduates.” As a result, there has been much conversation about both the potential and the possibilities with donor-derived lab-grown cells.
• OcuCell (ocucell.bio ). These endothelial cells are procured from a single donor. They are then grown in great numbers, such that a single donor can generate anywhere from 60 corneal grafts or more, according to the OcuCell website. These cells are seeded onto a biocompatible hydrogel material, which may offer distinct advantages: The tissue is easier to handle for surgeons (there is no graft scrolling), it has expanded quality controls, it has consistently higher cell counts than that of deceased single donors, and there is the potential to improve long-term outcomes.
Trials have yet to be performed in the United States with this company. That said, patients with pseudophakic corneal edema and Fuchs’ endothelial dystrophy would benefit from this technology.
• Aurion Biotech (aurionbiotech.com ). This cell therapy is comprised of fully differentiated human corneal endothelial cells with a rho kinase inhibitor in a proprietary solution. Specifically, endothelial cells are acquired from a human donor and then can be expanded in a proprietary process. In fact, cells from a single donor can replicate to produce more than 100 treatments. For treating patients who have corneal edema secondary to corneal endothelial dysfunction (of which Fuchs’ endothelial dystrophy is one of the most common diseases), the ophthalmologist polishes off the diseased endothelium, then implants healthy cells in solution with a rho kinase inhibitor into the anterior chamber of the patient’s eye. The cells quickly migrate and adhere to the stroma of the cornea.
Then, the patient lies face down for several hours; afterward, the patient can resume normal activities of daily living. In comparison to standard of care (endothelial keratoplasty, which requires surgical transplant of all or portions of a donor cornea), Aurion Biotech cell therapy is a minimally invasive procedure that enables a less onerous postoperative recovery for patients. The company says it intends to open a U.S. clinical trial soon. The cell therapy has already received regulatory approval in Japan.
Shaped Corneal Tissue
The latest iterations of shaped corneal tissue not used for endothelial cell replacement are primarily used to treat ectasia but are not exactly your father’s epikeratophakia (look it up!)…
• KeraNatural (www.visiongift.org/transplant/keranatural/ ). This is irradiated corneal tissue that is shaped into grafts that are analogous to intrastromal corneal ring segments. These precut segments are surgically implanted in a preformed channel also made by laser. Those who work with this type of tissue say that the purpose of this tissue is ultimately to improve the vision of keratoconus patients.1 KeraNatural is available now.
• Allotex (allotex.com ). This is an electron beam-sterilized tissue that has been fashioned to treat hyperopia or presbyopia. Specifically, the surgeon makes a thin flap in the recipient’s cornea using a femtosecond laser. The customized Allotex TransForm lenticule is then placed in the stromal bed, and the flap is re-placed and smoothed into place.
The company says that this improves near and intermediate vision, while maintaining distance vision as well, according to the company website. European clinical trials are complete, and U.S. trials may begin as early as the end of this year.
Antifungal Storage Media
• Kerasave (www.alchimiasrl.com/en/kerasave/ ). This is an FDA-approved storage media that can hold corneal graft tissue for up to 14 days. This media contains 2 antibiotics and a separate amphotericin B tablet that is to be added at the time of tissue recovery from the media. Some eye banks add the tablet after processing instead.
Lab data demonstrates the safety of amphoteriacin B (2.5 μg/mL) up to the 14-day mark. Evidence is not available that shows this affects the long-term viability of the tissue or overall graft failure rates. Debate continues amongst surgeons and eye banks as to how and when to add antifungals, and their usage remains sparse, according to the eye bank experts I spoke with for this article. Regardless of whether surgeons request antifungal supplementation, EBAA medical standards changed to require a double soak of 5% povidone-iodine prior to tissue recovery. (See “Research Article Spotlight,” p.32) This additive technology can be used in storage media for all corneal transplants.
Graft Diabetes Study
• Diabetes Endothelial Keratoplasty Study (DEKS). Eye banks estimate that approximately a third of corneal transplant grafts in the United States come from a person who had diabetes. Smaller studies have presented conflicting data as to the long-term and short-term viability of tissue from patients who had diabetes, so the DEKS Study was formed.
This is a National Institutes of Health–funded study that aims to shed enough light on this subject, so that surgeons use all the viable donor tissue possible, knowing that tissue truly gives the highest chance of success.
Specifically, the study will enroll 1,420 eyes and look at endothelial cell density and graft success rate at both the 1-month and 1-year marks, comparing normal tissue to diabetic tissue.
Additionally, the study will attempt to stratify the severity of diabetes in the patients who had diabetes and note any impact that this makes. Large and small centers in the private and academic world are participating in this study.2
Opportunities for New Surgeons
An increasing number of eye banks are providing more wet labs and opportunities to use gratis tissue for new surgeons. These surgeons, who are in their corneal fellowships, or have just completed them, benefit greatly from the ability to learn the newest techniques alongside experienced surgeons and eye bankers.
The eye banks provide surgery sessions at their facilities, and these are proctored by a local corneal surgeon or the medical director. They provide the tissue, teaching, and instrumentation needed for the surgery to increase cornea fellow surgical experience.
Market Changes
- Eye bank consolidation. This is a trend on the surgery side with the growing presence of private equity. A similar trend exists on the eye banking side, leading to larger eye bank conglomerates.
- “For profit” spinoffs. These allow for the diversification of offerings from eye banks. Many examples exist, including the ability to send a patient’s autologous serum tears, amniotic membrane tissue to surgeons, and various compounded medications needed for corneal surgeons to treat patients. These spinoffs can set up local labs to draw blood from the patient, and the blood is centrifuged to isolate the serum. It can be packed on ice and sent to the company. The company modifies the tears and delivers them to the patient to start therapy.
- Reimbursement. Cuts in and denials of reimbursements have led to eye banks getting involved in negotiations over contracts and claims on the ambulatory surgery center’s behalf.
- Steady shift to DMEK. While the desire for preloaded Descemet’s stripping automated endothelial keratoplasty graft tissue is up, an overall steady shift to DMEK is occurring, as delivering on the precision that is required to meet the demands of thinner corneal tissue continues to be difficult for eye banks.
Get and Stay Involved
Corneal surgeons can learn a lot from our eye banking colleagues, and we should push ourselves to do so. I have always admired the dedication and expertise that is displayed when I talk to eye bank folks or watch them work. This is a highly skilled and dedicated group that we must continue to work alongside toward our common goal of better serving our patients.
I would urge all corneal surgeons to contact their local eye bank and set up a visit to meet the entire team, learn how they process the tissue for transplants, and discuss tissue preferences for surgeries. CP
* Thanks to Chris Stoeger, CEO of Lions Vision Gift in Portland, Oregon; Tony Bavuso, CEO of Saving Sight in Kansas City, Missouri; and Eric Meinecke, president and CEO of Georgia Eye Bank in Georgia for their insights for this article.
EDITOR’S NOTE: All companies were contacted for fact-checking purposes. At press time, Allotex and Alchimia could not be reached for comment.
References:
- Haciagaoglu S, Tanriverdi C, Keskin FFN, Tran KD, Kilic A. Allograft corneal ring segment for keratoconus management: Istanbul nomogram clinical results. Eur J Ophthalmol. 2022 Dec 4:11206721221142995.
- Impact of Donor Diabetes on DMEK Success and Endothelial Cell Loss (DEKS). ClinicalTrials.gov . April 3, 2023. Accessed May 4, 2023. https://clinicaltrials.gov/ct2/show/NCT05134480 .
