Advancing Eye Banking: Lenticular Intrastomal Surgery And Post-Smile Stromal Corneal Lenticules As A New Resource

Lenticular Intrastromal Surgery (LIS) is an innovative approach in corneal transplantation and refractive correction, utilizing preserved stromal lenticules from ReLEx SMILE. This technique provides a minimally invasive solution for keratoconus, hyperopia, and corneal thinning disorders. Our study focuses on optimizing lenticule collection, preservation, and clinical application, ensuring structural and biological viability. By developing standardized protocols and long-term safety assessments, we aim to integrate LIS into routine ophthalmic practice, expanding the role of corneal lenticule banking.

This study was conducted at Fondazione Banca degli Occhi del Veneto (FBOV), a specialized eye bank and research center. Stromal lenticules from ReLEx SMILE were collected and preserved using cryopreservation (-80°C in DMSO) or controlled dehydration (2-8°C). Structural and optical properties were analyzed to optimize preservation techniques. The goal was to ensure lenticule viability for corneal surgery and regenerative applications, supporting future clinical use.

Stromal lenticules from ReLEx SMILE were preserved in Coldix or hyaluronic acid (HA) and transported to FBOV within 48 hours. Cryopreserved samples were stored at -80°C in DMSO and thawed at 37°C before analysis. Dehydrated samples were air-dried under sterile conditions for 1.5 hours, stored at 2-8°C, and rehydrated before evaluation.

Structural and optical assessments included:
- Histology (H&E, Masson, PAS) for stromal integrity
- OCT for thickness measurement
- Transparency and diameter assessment

Histological analysis confirmed that Coldix and HA-preserved lenticules maintained stromal integrity, with HA samples appearing more compact and Coldix showing intrastromal air bubbles. Thickness increased significantly in Coldix after 48 hours (p<0.0001), suggesting greater hydration. Transparency remained stable post-preservation and rehydration, with no significant differences between groups. Diameter was unchanged, confirming structural stability. Cryopreservation in DMSO preserved optical and stromal properties, making it a viable long-term storage option for keratoconus, hyperopia, and tectonic applications.

This study confirms that post-SMILE stromal lenticules can be effectively preserved for keratoconus, hyperopia, or tectonic applications. Coldix promotes greater tissue thickening, while HA ensures a more uniform collagen arrangement. Rehydration increases thickness, particularly in Coldix samples, but diameter and transparency remain stable, preserving tissue integrity. Cryopreservation in DMSO maintains stromal structure and optical properties, making it a viable long-term option for corneal surgery. Both Coldix and HA are suitable for short-term storage, supporting lenticule-based therapeutic solutions.