The Challenge: Progressive corneal thickening during storage complicates tissue assessment, affects graft preparation, and introduces variability into surgical planning. Traditional media typically show 10% thickness increase by day 14.

The XTRA4 Advantage: Corneas preserved in XTRA4 maintain near-baseline thickness throughout the storage period, with an average increase of just 2.4% over 14 days.

Clinical Impact:

• More accurate preoperative measurements
• Predictable graft dimensions for surgical planning
• Reduced variability in endothelial keratoplasty procedures
• Better correlation between day-1 assessment and surgical-day characteristics

Expert Perspective: “Whatever you see in the cornea stored in XTRA4 on day one is what you get when you go back to prepare it for surgery.” — Dr. Khoa Tran, PhD, VisionGift

The Challenge: Epithelial defects—common in eye banking—typically lead to rapid stromal swelling and edema in traditional storage media, compromising tissue assessment and potentially rendering tissue unsuitable for transplantation. The XTRA4 Advantage: Even with complete epithelial removal, corneas stored in XTRA4 maintain stromal clarity and thickness, showing no defect-related swelling or fold formation.

Clinical Impact:

• Greater flexibility in tissue selection
• More corneas remain suitable for transplantation
• Improved accuracy of specular microscopy assessment
• Enhanced confidence in tissue quality throughout storage

Practical Benefits:

• Reduced tissue waste due to epithelial compromise
• Better inventory management options
• Simplified quality control processes

The Challenge: DSAEK and DMEK procedures require precise graft thickness control. Even modest swelling can complicate tissue preparation, exceed injector lumen capacities, and contribute to endothelial cell loss.

The XTRA4 Advantage for DSAEK: Pre-cut DSAEK grafts stored in XTRA4 show only 7% thickness increase after 72-96 hours, maintaining predictable dimensions throughout storage and preparation.

The XTRA4 Advantage for DMEK: Minimal stromal swelling means fewer stress lines during preparation, leading to more consistent Descemet membrane peeling and reduced risk of tissue tears.

Clinical Impact:

• Smoother graft insertion with preloaded systems
• Reduced endothelial cell loss during preparation and delivery
• More predictable surgical outcomes
• Lower risk of graft detachment post-operatively

Expert Perspective:
“It provides confidence to eye bankers to tell their surgeons that the thickness of the tissue we cut is likely to remain very close to that during surgery.” — Dr. Onkar Sawant, PhD, Eversight

“If donors have compact stroma with fewer stress lines, we expect our outcomes will be better.” — Dr. Matthew Feng, MD

The Challenge: Endothelial cell viability determines graft success. Progressive cell loss during storage, accelerated by mechanical stress from stromal swelling, limits tissue quality and storage duration.

The XTRA4 Advantage: By maintaining physiological thickness, XTRA4 minimizes mechanical stress on endothelial cells.

Independent studies demonstrate:

• ≥ 98% endothelial cell viability through 14 days
• Average central cornea thickness increased by 2.4% in XTRA4 and 10% in Optisol-GS® between Day 1 and Day 14
• Preservation of normal cell morphology
• Minimal changes in endothelial cell density
• Preliminary data suggesting viability beyond 14 days, with potential for extended storage

Clinical Impact:

• Healthier grafts across all keratoplasty types (PK, DALK, DSAEK, DMEK)
• Reduced risk of postoperative complications
• Better long-term graft survival
• Potential for extended storage windows

Expert Perspective: “Every possible advantage to maintain endothelial function, at every step along the donor cornea’s journey, is going to benefit the patient.” — Dr. Matthew Feng, MD

The Challenge: Adopting new storage media often requires protocol changes, staff retraining, and validation studies—creating barriers to implementation.

The XTRA4 Advantage: XTRA4 is designed for drop-in compatibility with existing eye bank workflows:

• Works with standard corneal storage chambers
• Compatible with current tissue evaluation equipment
• No changes to established protocols required
• Suitable for both domestic and international distribution

Expert Perspective:
“It is compatible with what eye banks are already doing, which makes it very practical, not just for domestic use, but also for international tissue distribution.” — Dr. Khoa Tran, PhD, VisionGift