Figure 2

Electron micrograph of the posterior peripheral cornea. (A) Part of the posterior peripheral cornea, showing the endothelium (EN), pre-endothelial layer (PENL), Descemet’s membrane (DM), and pre-Descemet’s membrane layer (PDL). The PENL and PDL contained wide-spacing collagen, aggregates of microfibrils, and sheath material, consisting of electron-dense transverse bands (narrow-spacing fibers). DM had aggregates of the wide-spacing fibers located at its posterior surface. The major part of DM had a banding pattern. (B) Part of the PENL showing wide-spacing fibers containing dark bands (37.52 ± 4.99 nm) with a periodicity of 67.89 ± 5.91 nm, and the bands were connected by thin microfibrils (15.19 ± 3.00 nm). (C) Part of the PENL showing a sheath material consisting of electron-dense transverse bands forming a lattice. The sheath might be the outer part of the “elastic-like fibers” described by Lutjen-Drecoll et al.¹⁸ (D) Part of the PENL showing a cross-section of microfibrils (F1) with a diameter of 16.13 ± 4.24 nm. (E) Part of the PENL showing longitudinally running thin fibrils (F2) with a thickness of 10.14 ± 2.70 nm, just above the EN. These fibrils were described as fibrils of oxytalan fibers by Carrington et al.¹⁹. B electron-dense bands; CF collagen fibril, DM Descemet’s membrane, EN endothelium, F1 fibrils with a thickness of 16.13 ± 4.24 nm, F2 fibrils with a thickness of 10.14 ± 2.70 nm, MF microfibrils, NB narrow bands, PDL pre-Descemet’s membrane layer, PENL pre-endothelial layer, SH sheath material consisting of electron-dense bands (narrow banded fiber), WF wide-spacing fibers.