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The characteristics of the most popular intracorneal ring segment implants.
| Characteristics | INTACS | Ferrara Ring | Keraring |
|---|---|---|---|
| Arc, length/degree | 150 | 160 | 90,120,160,210,240 |
| Cross section | Hexagonal | Triangular | Triangular |
| Thickness/mm | 0.25–0.45 (0.05 increments) | 0.20–0.35 (0.05 increments) | 0.15–0.30 (0.05 increments) |
| Internal diameter/mm | 6.77 | 4.40 | 5.0 |
| External diameter/mm | 8.10 | 5.60 | 6.0 |
