Demographic characteristics of study subjects (mean±SD)
| Failed-PK-KCN | Primary KCN | Failed-PK-non-KCN | |
| n | 21 | 11 | 11 |
| Age (range) | 53.2±17.7 (18–72) | 45.8±16.3 (25–69) | 62.9±16.9 (35–95) |
| Laterality % Right Eyes | 57% | 64% | 64% |
| Penetrating keratoplasty | 19 | n/a | 11 |
| Deep anterior lamellar keratoplasty | 2 | n/a | 0 |
| Years between transplants (range) | 11.1±10.8 (0.25–36) | n/a | 4.9±6.8 (0.7–25) |
DALK, deep anterior lamellar keratoplasty; KCN, keratoconus; PK, penetrating keratoplasty.