Descemet Membrane Endothelial Keratoplasty With a Pull-Through Insertion Device: Surgical Technique, Endothelial Cell Loss, and Early Clinical Results.

PURPOSE: To describe a surgical technique for Descemet membrane endothelial keratoplasty (DMEK) using a pull-through, endothelium-in insertion device, the DMEK EndoGlide. We evaluated the endothelial cell loss (ECL) associated with the EndoGlide-DMEK (E-DMEK) technique in both ex vivo and prospective clinical studies. METHODS: The ex vivo study involved calcein acetoxymethyl staining and preparation of DMEK grafts, which were trifolded endothelium-in, loaded into the EndoGlide, pulled through, and unfolded in imaging dishes. Inverted fluorescent microscopy was performed, and ECL was quantified using trainable segmentation software. The prospective clinical series describes the outcomes of consecutive surgeries using the E-DMEK technique. Grafts were pulled through the EndoGlide with forceps and unfolded in the anterior chamber endothelium-down. Our main outcome measure was ECL in both studies. RESULTS: In the ex vivo study with 9 human donor corneas, mean ECL was 15.2% ± 5.4% (n = 9). In our clinical series of 69 eyes, leading indications for surgery were pseudophakic/aphakic bullous keratopathy (47.8%), previous failed grafts (23.2%), and Fuchs endothelial dystrophy (18.8%). Rebubbling and primary graft failure rates related to E-DMEK were 11.6% and 1.5%, respectively. Among eyes with at least 6 months of follow-up, mean preoperative endothelial cell density was 2772 (range 2457-3448) cells/mm, and postoperative endothelial cell density was 1830 (range 541-2545) cells/mm. Mean ECL was 33.6% (range 7.5-80.4; n = 32) at the 7.1 (range 6-11) months follow-up. CONCLUSIONS: The ex vivo and pilot clinical studies suggest that E-DMEK shows acceptable rates of ECL, with safe and promising early clinical outcomes.

Lamellar Dissection Technique for Descemet Membrane Endothelial Keratoplasty Graft Preparation.

PURPOSE: To describe a novel lamellar dissection technique for Descemet membrane endothelial keratoplasty (DMEK) graft preparation, and to evaluate the rate of endothelial cell loss (ECL) and graft preparation failure associated with this technique. METHODS: We conducted an ex vivo laboratory-based study comparing ECL between the lamellar dissection and peeling techniques. Eight pairs of human donor corneas underwent calcein acetoxymethyl staining-all right eyes underwent the peeling technique and all left eyes underwent the lamellar dissection technique. ECL was quantified by image analysis with trainable segmentation software and compared between groups. We also conducted a retrospective analysis of 161 consecutive DMEK graft preparations by a single surgeon using the lamellar dissection technique from 2010 to 2018. Data on donor characteristics and graft preparation failures were obtained. RESULTS: Baseline donor characteristics were comparable in both arms of the laboratory-based study. Mean (SD) ECL with the lamellar dissection and peeling techniques was 13.8% (4.2%) and 11.2% (6.1%), respectively. There was no significant difference between the two (P = 0.327). In the clinical series, there were 2 graft preparation failures in 161 cases (1.2%). Among cases performed on diabetic donor tissue, the rate of graft preparation failure was 4.7%. CONCLUSIONS: The lamellar dissection technique has a similar rate of ECL compared with the peeling technique for DMEK graft preparation. This technique also has a low rate of graft preparation failure and may be a useful technique for diabetic donor tissue.

Knowledge and attitudes toward corneal donation among Singaporean youth: a cross-sectional study.

BACKGROUND: To assess the knowledge of Singaporean youth regarding corneal donation and gauge their willingness to donate their corneas. METHODS: We conducted a cross-sectional study among 500 students from five tertiary institutions in Singapore. All students answered self-administered questionnaires which included seven questions that tested knowledge and three questions that determined willingness to donate corneas. RESULTS: Among 500 Singaporean youth aged 18 to 25, most students (73.2 %) answered 3 or fewer of the 7 questions about corneal donation correctly. With regards to the willingness to donate, 155 (31 %) were willing to donate their corneas, 111 (22.2 %) were not willing to donate their corneas, and 234 (46.8 %) were undecided. Willingness to donate corneas was associated with an older age group (21 to 25 years old), those who are non-Muslims, and have good basic knowledge. Particularly, students with good basic knowledge were 1.71 times more likely to willingly donate their corneas. CONCLUSION: The knowledge of the Singaporean youth regarding corneal donation and transplantation is poor. Since insufficient information was cited as the most common reason for being undecided in regards to corneal donation, specific and tailored programs to increase knowledge and awareness are needed to convince the youth to support corneal donation.

Risk factors for donor endothelial loss in eye bank-prepared posterior lamellar corneal tissue for descemet stripping automated endothelial keratoplasty.

PURPOSE: The aim of this study was to investigate donor, tissue, and precut procedure risk factors for endothelial cell density (ECD) loss in posterior lamellar corneal tissue preparation by an eye bank for Descemet stripping automated endothelial keratoplasty. METHODS: A total of 259 corneoscleral rims precut by the Singapore Eye Bank from October 2011 to August 2013 were evaluated. Donor characteristics, tissue characteristics, and precut procedure parameters were analyzed. RESULTS: The mean donor age was 57.18 ± 11.35 years, and the mean cutting transition time was 4.16 ± 0.75 seconds. The mean ECD was 2826 ± 225 and 2787 ± 224 cells per square millimeter before and after precutting, respectively, with an average ECD change of -1.38% ± 3.28%. The precutting procedure failure rate was 1.2%. Mutivariate regression analysis showed that an older donor age, a higher ECD before cutting, and a slower cutting transition speed were significant factors. Corneas with an ECD >2800 cells per square millimeter before precutting, cutting transition time >5.5 seconds, and corneas with donor age >65 years were significantly more likely to have greater than 5% ECD loss after precutting (odds ratio, 6.42, 1.66, and 1.62; 95% confidence interval, 1.44-29.43, 1.45-2.72, and 1.66-5.82, respectively). Donor source, death-to-preservation time (range, 0.67-10.88 hours), death-to-precutting time (range, 0-7 days), and graft thickness (range, 43-232 µm) were not statistically significant factors. CONCLUSIONS: The ECD loss in the precut tissue prepared by the eye bank was very low. The risk factors identified provide better understanding of how to improve the quality and safety profiles when preparing graft tissue for Descemet stripping automated endothelial keratoplasty.