Optimizing Visualization of Descemet Membrane Endothelial Keratoplasty Tissue: Assessing the Impact of Trypan Blue Exposure on Stain Duration and Corneal Endothelial Cell Function.

PURPOSE: To assess how trypan blue staining affects Descemet membrane endothelial keratoplasty (DMEK) graft visibility and corneal endothelial cell (CEC) mitochondrial respiration. METHODS: DMEK grafts (n = 20) were stained with trypan blue 0.06% for 1, 3, 5, or 10 minutes. Each graft was injected into an artificial anterior chamber. Surgery was simulated with tapping and sweeping motions on the corneal surface and injections of balanced salt solution (BSS). Graft visibility was assessed at 5, 10, 20, and 30 minutes. Effects of trypan blue on mitochondrial respiration were assessed using primary CECs cultured from donor corneas (n = 43). Treatment wells exposed to trypan blue 0.06% (1, 5, or 30 minutes) and donor-matched control wells to methylene blue 1% (1 minute) or BSS (1, 5, or 30 minutes) were assayed for key respiration parameters. RESULTS: After 5 minutes of surgical manipulation, grafts stained for 5 minutes were significantly more visible than grafts stained for 1 or 3 minutes; there was no added benefit of staining for 10 minutes. After 10 minutes of surgical manipulation, grafts stained for 3 minutes were more visible than grafts stained for 1 minute, without additional benefits of staining ≥5 minutes. No visibility differences were observed after ≥20 minutes of surgical manipulation. CEC mitochondrial respiration did not change significantly following trypan blue exposure for all intervals tested compared to BSS. CONCLUSIONS: Staining DMEK grafts with trypan blue for 3 to 5 minutes optimizes visibility during surgical manipulation without mitochondrial impairment. Corneal surgeons learning DMEK will benefit from optimizing this critical step.

A Simple 60-Second Swelling Technique for More Consistent Ultrathin DSAEK Graft Preparation.

PURPOSE: The purpose of this study is to describe a simple but novel 60-second swelling technique for ultrathin Descemet stripping automated endothelial keratoplasty (DSAEK) graft preparation. In addition, we aim to demonstrate the effectiveness of this technique in obtaining thinner DSAEK grafts more consistently without compromising graft quality. METHODS: We performed a retrospective case-control study comparing standard DSAEK preparation using an ML7 Microkeratome Donor Cornea System (Med-Logics Inc, Athens, TX) with an additional 60 seconds of stromal swelling with a balanced salt solution after the removal of the epithelium but before the microkeratome pass. Thirty cases using this novel swelling technique were compared with controls matched by age, sex, and precut corneal thickness. Donor characteristics and both precut and postcut graft characteristics were analyzed. RESULTS: DSAEK grafts prepared with our simple swelling method were approximately 13 µm thinner on average than those prepared with our conventional ultrathin DSAEK preparation technique (P = 0.001). The frequency of grafts less than 100 µm was much greater with swelling (93.3% vs. 63.3% with conventional technique, P = 0.0052). There were no significant differences in postcut cell counts or decrease in cell counts between the groups. CONCLUSIONS: A simple 60-second swelling technique can yield significantly thinner DSAEK tissue in a more consistent range without a significant impact on the endothelial cell count.