Evaluation of interface quality in organ-cultured lamellar corneal transplants

Background: With increasing numbers of lamellar keratoplasties, eye banks are challenged to deliver precut lamellar donor tissue. In Europe, the most common technique of corneal storage is organ culture which requires a deswelling process before surgical processing. The aim of this study was to investigate the influence of different deswelling times on the cutting plane quality after microkeratome-assisted lamellar dissection. Methods: Eight paired donor corneas (16 specimens) not suitable for transplantation were organ cultured under standard conditions at the Eye Bank of the Ludwig-Maximilians Universität, Munich, Germany. Pairs of corneal buttons were analyzed during the deswelling process in dextrane-containing medium. While one cornea was cut at an early time point during the deswelling process and put back into deswelling medium thereafter, the partner cornea was completely deswollen and dissected after 72 hours. Specimens were then further processed for scanning electron microscopy. Surface quality was assessed both digitally using Scanning Probe Imaging Processing software, and manually by three blinded graders. Results: The corneal buttons processed at the beginning of the deswelling process had a smoother surface when compared to the partner cornea that was cut at the end of the deswelling process. In our setting, no relevant difference was detectable between manual and automated microkeratome dissection. Conclusion: For lamellar keratoplasty, organ-cultured corneas should be processed at an early stage during the deswelling process. We interpret the smoother dissection plane during early deswelling as a result of mechanical properties in a highly hydrated cornea

An in vivo evaluation of Brilliant Blue G in animals and humans

Background/Aims: To evaluate the retinal toxicity of Brilliant Blue G (BBG) following intravitreal injection in rat eyes and examine the biocompatibility and the staining properties in humans.Methods: BBG was injected into the 11 rat eyes to evaluate toxic effects with balanced salt solution (BSS) serving as control. Retinal toxicity was assessed by retinal ganglion cell (RGC) counts and by light microscopy 7 days later. In addition, BBG was applied during vitrectomy for macular hole (MH) (n = 15) or epiretinal membranes (ERM) (n = 3) in a prospective, non-comparative consecutive series of patients. Before and after surgery, all patients underwent a complete clinical examination including measurement of best corrected visual acuity (VA) and intraocular pressure, perimetry, fundus photography and optical coherence tomography. Patients were seen 1 day before surgery and then in approximately four weeks intervals.Results: No significant reduction in RGC numbers and no morphological alterations were noted. A sufficient staining of the internal limiting membrane (ILM) was seen in patients with MH, while the staining pattern in ERM cases was patchy, indicating that parts of the ILM were peeled off along with the ERM in a variable extent. All MHs could be closed successfully. VA improved in 10 eyes (56%; 8/15 MH patients, 2/3 ERM patients), was unchanged in four eyes (22%; all MH patients) and was reduced in four eyes (22%; 3/15 MH, 1/3 ERM). No toxic effects attributable to the dye were noted during patient follow-up. The ultrastructure of tissue harvested during surgery was unremarkable.Conclusion: Brilliant Blue provides a sufficient and selective staining of the ILM. No retinal toxicity or adverse effects related to the dye were observed in animal and human studies. The long-term safety of this novel dye will have to be evaluated in larger patient series and a longer follow-up