Osmic acid solution

The eye samples were prefixed in 2.7% glutaraldehyde solution (Sigma-Aldrich, St Louis, Missouri) in 0.1 M phosphate buffer, then washed in 0.15 M phosphate buffer (pH 7.2), and postfixed in 2% osmic acid solution (Sigma-Aldrich, St Louis, Missouri) in 0.15 M phosphate buffer. Dehydration was performed in acetone, followed by embedding in the epoxy resin (Epon 812). Thin sections of 70 nm thickness were cut on a Leica EM UC7 ultramicrotome (Leica Microsystems GmbH, Wetzlar, Germany). The double staining of thin sections on grids was performed with solutions of uranyl acetate and lead citrate. The sections were imaged under a TEM (Morgagni268, FEI, Eindhoven, Netherlands) at 80 kV. Data acquisition was performed with a MegaView III CCD using iTEM SIS software (Olympus Soft Imaging Software, Munster, Germany).

The eye samples were prefixed in 2.7% glutaraldehyde solution (Sigma-Aldrich, St Louis, MO, USA) in 0.1 M phosphate buffer; then, washed in 0.15 M phosphate buffer (pH 7.2) and post-fixed in 2% osmic acid solution (Sigma-Aldrich, St Louis, MO, USA) in 0.15 M phosphate buffer. Acetone was used for dehydration, followed by inclusion in the epoxy embedding resin Epon 812. Ultrathin sections of 70 nm sections were cut on Leica EM UC7 ultramicrotome (Leica Microsystems GmbH, Wetzlar, Germany) and doubly contrasted with solutions of uranyl acetate and lead citrate and analyzed with TEM (Morgagni 268, FEI, Eindhoven, Netherlands) at 80 kV. Data acquisition was performed with a MegaView III CCD using iTEM SIS software (Olympus Soft Imaging Software, Munster, Germany).