Gelfoam 12 7 mm

At 72 h prior to LGE or sham surgery tracers were applied to the cornea, including FluoroGold (FG, 3% in Na⁺Cl⁻; Fluorochrome, Denver, CO, USA), Fast Blue (FB, 5% in Na⁺Cl⁻; PolySciences, Warrington, PA), FM-143x (FM, 5% in NaCl, ThermoFisher Scientific, Waltham, MA, USA) and 1,1′-dioctadecyl-3,3,3′3,3′ -tetramethyl-indocarbocyanine perchlorate (DiI, 5% in 20% DMSO in H₂O, ThermoFisher Scientific, Waltham, MA, USA). Under isoflurane anesthesia, a DC current (7 μA for 10 min) (Kumar et al., 2017 ) was passed between a copper wire in a capillary tube filled with either a single tracer or a combination of two (FG/FM143x, FB/FM143x, FG/DiI) and a copper cathode placed in the tail (Fig. 1A). An absorbent gelatin sponge (Gelfoam 12–7 mm; Pfizer Pharmaceuticals, New York, NY) was cut, inserted into the capillary tube, and placed in contact with both the cornea and the tracer solution within the capillary tube, thus allowing the current to pass through to the cornea (Cassagne et al., 2016 (link)). In preliminary studies, iontophoresis did not produce signs of epithelial damage as evidenced by an absence of corneal fluorescein staining.