Table 2. Tissue hydration and collagen parameters measured before (CXL-) and after (CXL+) riboflavin/UVA collagen cross-linking.
| Sample | Hydration | Fibril Diameter (nm) | Interfibrillar Spacing (nm) | D-period (nm) | ||||
| CXL− | CXL+ | CXL− | CXL+ | CXL− | CXL+ | CXL− | CXL+ | |
| Hypo-osmolar riboflavin/UVA cross-linking: Keratoconus | ||||||||
| K1 | 2.2 | 4.0 | 31.1 (0.1) | 32.8 (0.1) | 38.3 (0.3) | 47.3 (0.2) | 65.4 (0.1) | 65.5 (0.1) |
| K2 | 3.8 | 6.0 | 31.6 (0.1) | 32.0 (0.2) | 49.7 (0.3) | 61.2 (0.4) | 65.5 (0.1) | 65.4 (0.1) |
| Hypo-osmolar riboflavin/UVA cross-linking: Normal | ||||||||
| N1 | 2.3 | 3.5 | 34.5 (0.1) | 34.8 (0.1) | 48.1 (0.1) | 51.1 (0.2) | 65.2 (0.1) | 65.2 (0.1) |
| N2 | 2.4 | 4.1 | 32.9 (0.3) | 32.7 (0.2) | 48.2 (0.2) | 52.6 (0.2) | 66.1 (0.1) | 66.1 (0.1) |
| N3 | 2.1 | 2.9 | 34.3 (0.1) | 34.6 (0.1) | 50.5 (0.1) | 52.6 (0.2) | 65.2 (0.1) | 65.2 (0.1) |
| N4 | 2.5 | 3.4 | 33.4 (0.1) | 33.8 (0.1) | 50.7 (0.3) | 54.2 (0.3) | 66.1 (0.1) | 66.1 (0.1) |
| N5 | 6.6 | 6.9 | 33.8 (0.2) | 33.5 (0.1) | 58.6 (0.4) | 60.2 (0.3) | 64.7 (0.1) | 64.5 (0.1) |
| N6 | 6.6 | 6.8 | 33.2 (0.2) | 33.8 (0.4) | 57.9 (0.3) | 57.2 (0.3) | 63.7 (0.1) | 63.5 (0.1) |
| Iso-osmolar riboflavin/UVA cross-linking: Normal | ||||||||
| N7 | 2.0 | 2.2 | 33.6 (0.1) | 31.0 (0.1) | 50.0 (0.1) | 39.2 (0.1) | 66.1 (0.1) | 66.1 (0.1) |
| N8 | 1.9 | 1.8 | 33.5 (0.1) | 32.4 (0.1) | 49.2 (0.3) | 44.9 (0.3) | 65.2 (0.1) | 65.2 (0.1) |
| N9 | 2.5 | 2.7 | 34.0 (0.1) | 31.9 (0.1) | 49.1 (0.2) | 41.6 (0.3) | 65.2 (0.1) | 65.2 (0.1) |
| N10 | - | 5.4 | - | 33.1 | - | 46.5 | - | 66.0 |
| N11 | 5.7 | - | 33.7 | - | 49.1 | - | 66.0 | - |
| N12 | - | 5.1 | - | 33.3 | - | 48.5 | - | 66.0 |
| N13 | 5.3 | - | 32.1 | - | 49.1 | - | 66.0 | - |
| N14 | - | 4.7 | - | 33.3 | - | 50.4 | - | 66.0 |
| N15 | 5.2 | - | 33.7 | - | 51.0 | - | 66.0 | - |
Average values (+/− SEM) of collagen parameters for all samples (excluding N10–N15) were calculated using >50 measurements recorded from the central 8 mm region of the same corneas before (CXL−) and after cross-linking (CXL+). Averaged data shown for samples N10–N15 (3 pairs of corneas in which the left of each pair (N10, N12 and N14) was cross-linked (CXL+) and the right (N11, N13 and N15) remained untreated (CXL−)) is based on a single measurements obtained from the centre of each cornea. Bold type is used to indicate pre and post treatment differences in collagen parameters at p<0.001.