Abstract
Purpose :
To determine if Patent blue (PB), used as a food coloring and in lymph node mapping, can be used as an alternative dye during DMEK surgery for applications in regions where Trypan blue (TB) is not approved for use.
Methods :
For stain retention, DMEK grafts were stained with 2.5% PB for 4 min and 10 min (n=4) and compared to 0.06% TB for 4 min. Stained grafts were washed with 5 mL of BSS in a 6-well dish with continuous agitation. Stain retention was tracked using video and still images over a 15 min period and grading according to a serial dilution series of PB. Three additional grafts stained with 2.5% PB for 10 minutes prior to use in mock surgeries to assess stain retention for 25 minutes after injection and manipulation in a donor eye. To assess the safety of PB, DMEK grafts were prepared from pairs of corneas with one stained in 0.06% TB for 4 min while its mate was stained with 2.5% PB for 10 min (n=10 pairs). Grafts were then loaded into a Straiko modified Jones tube and stored in a viewing chamber filled with Optisol-GS at 4°C for 5 days. Endothelial cell loss (ECL) was quantified using Calcein-AM staining and FIJI segmentation by two masked readers.
Results :
PB Stain intensities were 2 grades lighter than TB after both were subjected to 15 min of BSS washing. Grafts stained with 2.5 % PB for 10 minutes retained sufficient color for the duration of mock surgery for 25 minutes. The average ECL for grafts stained with PB was 21.6% ± 5.3% in reader #1 [95% confidence interval (CI), 18.3%-24.9%] and 23.6% ± 4.8% in reader #2 (95% CI, 20.7%-26.6%). Likewise, the average ECL for grafts stained with TB was 20.2% ± 5.4% in reader #1 (95% CI, 16.8%-23.6%) and 21.2% ± 5.8% in reader #2 (95% CI, 17.7%-24.8%). No difference of ECL was found between two dyes in reader #1 (p=0.202) and reader #2 (p=0.092). In addition, the results of two readers had acceptable agreement (p=0.169).
Conclusions :
Patent blue is a viable alternative dye for DMEK surgery for applications where Trypan blue may not be available.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.