Table 2.
Mean change in visual, refractive and tomographic parameters over 24 months
| Preoperative | 12 months | 24 months | P1a | P2b | |
|---|---|---|---|---|---|
| UDVA (logMAR) | 0.81 ± 0.40 (0.12–1.58) | 0.81 ± 0.40 (0.18–1.60) | 0.88 ± 0.41 (0.06–2.08) | 0.97 | 0.08 |
| CDVA (logMAR) | 0.38 ± 0.32 (0.12–1.58) | 0.32 ± 0.20 (0.18–1.60) | 0.30 ± 0.21 (0.06–2.00) | 0.12 | <0.01 |
| MRSE (D) | −5.32 ± 5.00 (−19.25–1.00) | −5.01 ± 5.47 (−16.25–1.87) | −4.67 ± 5.40 (−16.37–1.25) | 0.54 | 0.19 |
| KMean (D) | 50.45 ± 3.99 (44.3–61.5) | 50.82 ± 4.05 (44.3–61.3) | 50.36 ± 3.87 (44.2–61.6) | 0.87 | 0.93 |
| KMax (D) | 59.13 ± 7.40 (46.6–80.7) | 60.08 ± 7.24 (48.1–78.6) | 58.73 ± 7.13 (47.1–80.6) | 0.96 | 0.78 |
| Anterior astigmatism (D) | 4.27 ± 2.44 (0.4–9.0) | 4.48 ± 2.24 (0.7–7.9) | 4.31 ± 2.19 (1.7–9.8) | 0.74 | 0.98 |
| CTP (um) | 419 ± 42 (335–529) | 421 ± 48 (305–530) | 434 ± 47 (293–538) | 0.93 | 0.21 |
| Asphericity (Q) | −1.02 ± 0.51 (−1.89 to −0.22) | −1.03 ± 0.53 (−1.83 to −0.14) | −1.00 ± 0.52 (−1.95 to −0.26) | 0.82 | 0.96 |
| ISV | 97.12 ± 42.58 (25–192) | 99.08 ± 39.49 (44–194) | 93.68 ± 40.9 (27–175) | 0.82 | 0.70 |
| IVA | 0.93 ± 0.50 (0.11–1.77) | 0.94 ± 0.49 (0.13–1.72) | 0.89 ± 0.46 (0.06–1.70) | 0.71 | 0.68 |
| KI | 1.27 ± 0.16 (0.99–1.71) | 1.28 ± 0.17 (0.87–1.75) | 1.25 ± 0.15 (0.92–1.58) | 0.89 | 0.61 |
| CKI | 1.08 ± 0.06 (0.98–1.22) | 1.08 ± 0.07 (0.94–1.23) | 1.07 ± 0.06 (0.94–1.23) | 0.38 | 0.68 |
| IHA | 31.9 ± 25.24 (1.0–101.3) | 39.38 ± 25.86 (0.1–93.3) | 42.33 ± 36.1 (0–164.2) | 0.12 | 0.20 |
| IHD | 0.14 ± 0.08 (0.00–0.34) | 0.15 ± 0.08 (0.04–0.33) | 0.13 ± 0.08 (0.00–0.33) | 0.79 | 0.82 |
Significant p-values are given in bold
CTP Cornea thinnest point, ISV index of surface variance, IVA index of vertical asymmetry, KI keratoconus index, CKI center keratoconus index, IHA index of height asymmetry, IHD index of height decentration
aPaired t-test, comparison of preoperative and year 1 values
bPaired t-test, comparison of preoperative and year 2 values