Table 2.
Preoperative and postoperative corneal astigmatism
| variance | Mean ± SD | 95%CI | minimum | maximum | |
|---|---|---|---|---|---|
| Anterior corneal | Astigmatism (D) | 1.58 ± 0.61 | 1.42,1.73 | 0.70 | 3.70 |
| K1 (D) | 43.36 ± 1.67 | 42.92,43.79 | 39.20 | 46.60 | |
| K2, (D) | 44.96 ± 1.64 | 44.54,45.38 | 41.40 | 48.60 | |
| Astigmatism (D) | 1.26 ± 0.68* | 1.08,1.44 | 0.30 | 3.30 | |
| K1, (D) | 43.32 ± 1.74 | 42.87,43.77 | 39.20 | 46.90 | |
| K2, (D) | 44.61 ± 1.68 | 44.18,45.05 | 40.50 | 48.00 | |
| Posterior corneal | Astigmatism (D) | 0.28 ± 0.22 | 0.22,0.33 | 0.00 | 0.80 |
| K1 (D) | −6.28 ± 0.25 | −6.35, −6.22 | −6.80 | −5.80 | |
| K2, (D) | −6.55 ± 0.27 | −6.62, − 6.48 | −7.20 | −6.00 | |
| Astigmatism (D) | 0.41 ± 0.26* | 0.35,0.48 | 0.00 | 1.10 | |
| K1, (D) | −6.33 ± 0.28* | −6.41, − 6.26 | −5.80 | −6.90 | |
| K2, (D) | −6.75 ± 0.37* | −6.85, − 6.66 | −6.10 | −7.70 | |
The shaded part represents preoperative corneal astigmatism; and the non-shaded parts represent postoperative corneal astigmatism. Asterisk* represents a significant difference (P < 0 .05) compared with the preoperative astigmatism. SD standard deviation, CI confidence interval, D diopters, K1 keratometric value at the flattest corneal meridian, K2 keratometric value at the steepest corneal meridian