Femtosecond and excimer laser-assisted endothelial keratoplasty (FELEK): a new technique of endothelial transplantation.

PURPOSE: To describe a new technique of endothelial keratoplasty (EK) that improves the quality of lamellar dissection of donor cornea. METHODS: We compared four techniques of donor cornea preparation for lamellar dissection on 8 donor corneas: mechanical dissection with a microkeratome, a single femtosecond laser lamellar cut, a double femtosecond laser lamellar cut and combined femtosecond laser lamellar dissection with excimer laser surface photoablation. The quality of the donor cornea interface was assessed and compared using scanning electron microscopy (SEM), and the most satisfactory technique was employed for EK on three patients. The postoperative anatomic results were analyzed with anterior segment spectral-domain optical coherence tomography (SD-OCT) and in vivo confocal microscopy (IVCM). RESULTS: The smoothest stromal interface was observed on SEM with the combined use of femtosecond laser dissection and excimer photoablation. The surgical procedures performed with donor cornea prepared by a combination of femtosecond and excimer lasers resulted in clear corneas after 1 month. SD-OCT showed good attachment of the endothelial graft and a hyperreflective interface. On IVCM, subepithelial haze, honeycomb-like activated keratocytes and needle-shaped particles were visible in the recipient corneal stroma as well as numerous hyperreflective particles on the donor-recipient interface. CONCLUSION: A new technique, femtosecond and excimer laser-assisted endothelial keratoplasty (FELEK), which refines the current limitations observed in Descemet-stripping automated endothelial keratoplasty (DSAEK), is described. Femtosecond laser dissection provides a thin and reproducible endothelial graft cut with a high level of safety and accuracy, while excimer photoablation yields a smooth, high-quality interface.

Long-term stability of bevacizumab repackaged in 1mL polypropylene syringes for intravitreal administration.

INTRODUCTION: The anti-angiogenic monoclonal antibody, bevacizumab, is currently used by intravitreal administration as off-label drug to treat age-related macular degeneration or other ophthalmologic diseases. For this purpose, commercial bevacizumab is repackaged in 1mL polypropylene syringes under sterile conditions. However, no complete study on the stability of this hospital-based preparation is available. METHODS: Commercial bevacizumab (25mg/mL; Avastin(®)) was aseptically repackaged in 1mL polypropylene syringes, stored at 4°C, and analyzed within the preparation day (D0), after 30 days (D30) and 90 days (D90). Some syringes were kept for up to 8 months to observe possible instability. Several complementary and stability-indicating analytical methods were used to assess in details the primary, secondary and tertiary structure of the antibody during its conservation: ionic chromatography, size-exclusion chromatography, peptide mapping, 2nd derivative UV and IR spectroscopy, turbidimetry, diffraction laser spectroscopy, thermal denaturation curves, microscopic examination and image analysis. RESULTS: We clearly demonstrate that the commercial solution of bevacizumab can be safely repackaged in polypropylene syringes and stored up to 3 months at 4°C without alteration of its primary, secondary and tertiary structure. The only difference observed is the contamination of the syringe content by silicone oil microdroplets, which is quite immediate and does not change significantly during the storage in terms of number and size. CONCLUSION: Our results support the off-label use of repackaged bevacizumab by intravitreal administration, at least from a pharmaceutical point of view, with a validated stability of 3 months. This stability period is largely enough to practical situations and support current practices, such as in advance or batch preparations, which present major advantages in terms of GMP respect, workload optimization and financial savings.