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