Table 3.
Outcomes of the Q value-based nomogram in adult 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 | 1.11 ± 0.31 1.1 (0.6 to 1.7) |
0.55 ± 0.21 0.5 (0.2 to 1.1) |
-0.56 (-0.66 – -0.46) | < 0.001 |
| CDVA | 0.57 ± 0.17 0.5 (0.3 to 0.9) |
0.17 ± 0.14 0.1 (0.0 to 0.7) |
-0.40 (-0.46 – -0.34) | < 0.001 |
| Sphere | -4.12 ± 1.33 -3.5 (-6.8 to -2.0) |
-1.05 ± 0.75 -1 (-3.3 to -0.3) |
3.07 (2.69 – 3.45) | < 0.001 |
| Cylinder | -3.15 ± 1.78 -3.0 (-7.8 to -0.50) |
-2.45 ± 1.34 -2 (-6.5 to -0.5) |
0.70 (0.23 – 1.18) | 0.004 |
| SE | -5.69 ± 1.57 -4.9 (-8.0 to -2.5) |
-2.28 ± 1.03 -2.3 (-4.9 to -0.9) |
3.42 (2.96 – 3.88) | < 0.001 |
| K1 | 46.20 ± 2.26 45.6 (43.2 to 52.4) |
43.06 ± 2.43 42.9 (36.5 to 50.2) |
-3.14 (-3.60 – -2.67) | < 0.001 |
| K2 | 49.49 ± 2.84 44.9 (40.4 to 51.2) |
45.49 ± 2.84 44.9 (40.4 to 51.2) |
-4.05 (-4.67 – -3.43) | < 0.001 |
| Kaverage | 47.87 ± 2.36 47.1 (44.5 to 53.4) |
44.27 ± 2.52 44.2 (38.6 to 50.7) |
-3.60 (-4.06 – -3.13) | < 0.001 |
| Kmax | 55.07 ± 4.38 54.4 (46.7 to 65.6) |
49.82 ± 4.36 49.6 (42.8 to 61.5) |
-5.26 (-6.57 – -3.95) | < 0.001 |
| TCT | 439.30 ± 34.48 439.0 (384.0 to 516.0) |
443.06 ± 33.12 439.0 (386.0 to 509.0) |
3.75 (-0.18 – 7.69) | 0.06 |
| Q-ant | -0.96 ± 0.31 -0.9 (-1.5 to -0.6) |
-0.41 ± 0.33 0.4 (-1.3 to -0.0) |
0.55 (-0.42 – 0.67) | < 0.001 |
| Q-post | -1.16 ± 0.31 -1.2 (-1.8 to -0.5) |
-1.13 ± 0.37 -1.2 (-1.8 to -0.2) |
0.03 (-0.05 – 0.11) | 0.44 |
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; Adult group included patients aged ≥ 18 years with intolerance to spectacles and gas permeable contact lenses, stable keratoconus for at least one year (Kmax remained < 1 diopter [D]), 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]. The cone asymmetry was type 1 and type 2 (100% and 80% of the cones were on one side of the steepest meridian, respectively), and the TCT should be > 380 μm.