Table 4.
Outcomes of the Q value-based nomogram in pediatric group with keratoconus
| Variable | Preoperative | Six month postoperative | Difference (post - pre) | P -value |
|---|---|---|---|---|
|
Mean ± SD
Median (Range) |
Mean ± SD
Median (Range) |
Mean (95 % CI) | ||
| UDVA | 1.09 ± 0.27 1.1 (0.8 to 1.7) |
0.47 ± 0.22 0.4 (0.2 to 0.9) |
-0.62 (-0.82 – -0.42) | 0.001 |
| CDVA | 0.53 ± 0.14 0.5 (0.4 to 0.8) |
0.19 ± 0.22 0.1 (0.0 to 0.8) |
-0.34 (-0.44 – -0.24) | 0.001 |
| Sphere | -4.48 ± 1.27 -4.37 (-6.5 to -2.5) |
-1.30 ± 0.88 -1.0 (-3.0 to -0.3) |
3.18 (2.44 – 3.92) | 0.001 |
| Cylinder | -3.14 ± -1.47 -3.3 (-6.5 to -1.0) |
-2.16 ± 0.87 -2.0 (-3.8 to -1.0) |
0.98 (0.001 – 1.96) | 0.051 |
| SE | -6.05 ± 1.26 -6.3 (-8.0 to -4.4) |
-2.38 ± 0.97 -2.3 (-4.3 to -1.0) |
3.67 (2.68 – 4.66) | 0.001 |
| K1 | 46.41 ± 1.51 46.3 (43.9 to 49.1) |
43.00 ± 2.06 43.5 (39.2 to 45.2) |
-3.41 (-4.70 – -2.12) | < 0.001 |
| K2 | 49.65 ± 1.83 49.7 (46.4 to 53.4) |
45.28 ± 1.46 45.8 (42.1 to 46.5) |
-4.37 (5.65 – -3.10) | < 0.001 |
| Kaverage | 48.03 ± 1.45 48.2 (45.4 to 50.1) |
44.14 ± 1.71 44.7 (40.7 to 45.8) |
-3.89 (-5.05 – -2.73) | < 0.001 |
| Kmax | 56.14 ± 4.08 56.2 (48.7 to 62.7) |
50.8 ± 3.5 50.8 (44.2 to 56.5) |
-5.37 (-6.37 – -4.36) | < 0.001 |
| TCT | 457.29 ± 30.31 458.0 (396.0 to 494.0) |
452.21 ± 33.93 449.0 (392.0 to 505.0) |
-5.07 (-11.12 – 0.98) | 0.09 |
| Q-anterior | -1.17 ± 0.40 -1.3 (-1.7 to -0.3) |
-0.53 ± 0.33 -0.5 (-1.2 to -0.02) |
0.62 (0.39 – 0.89) | 0.002 |
| Q-posterior | -1.26 ± 0.51 -1.3 (-2.0 to -0.1) |
-1.27 ± 0.47 -1.3 (-1.9 to -0.1) |
-0.01 (-0.14 – 0.12) | 0.89 |
Abbreviations: Post, postoperative values at 6 months; Pre, preoperative values; SD, standard deviation; CI, confidence interval; UDVA, uncorrected distance visual acuity; CDVA, corrected distance visual acuity; Sphere, spherical component of refractive error; Cylinder, cylindrical component of refractive error; SE, spherical equivalent of refractive error calculated as sphere + 1/2 cylinder; K1, front keratometry in flat meridian; K2, front keratometry in steep meridian; Kaverage, front mean keratometry; Kmax, front maximum keratometry; TCT, thinnest corneal thickness; Q-ant, asphericity of the anterior corneal surface; Q-post, asphericity of the posterior corneal surface. Note: P-values < 0.05 are shown in bold; Pediatric group included patients aged 14 – 17 years with intolerance to spectacles and gas permeable contact lenses, grade 1 and 2 Amsler – Krumeich classification (A-K; Kaverage ≤ 48 D with < - 5 D myopia and astigmatism, 48 – 53 D with 5 – 8 D myopia and astigmatism, respectively) [13], type 1 and 2 cone asymmetry, TCT > 380 μm, and SE worse than - 4 D.