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Table 2 Visual, refractive, tomographic, aberrometric, and densitometric parameters 12 months and 24 months postoperatively in eyes treated with central corneal regularization combined with corneal cross-linking and in eyes treated with corneal cross-linking as a single procedure

From: Changes in higher order aberrations after central corneal regularization - a comparative two-year analysis of a semi-automated topography-guided photorefractive keratectomy combined with corneal cross-linking

 CXL-Plus group
(n = 28)
CXL group
(n = 28)
CXL-Plus group
(n = 16)
CXL group
(n = 10)
p1 (CXL-Plus group 12 vs. 24)*p2 (CXL 12 vs. 24)*p3 (CXL-Plus vs. CXL 24)
12 months follow-up24 months follow-up
Mean (SD)Mean (SD)Mean (SD)Mean (SD)   
UDVA(logMAR)0.36 (0.29)0.46 (0.37)0.53 (0.51)0.29 (0.28)0.5700.2010.187
BSCVA(logMAR)0.10 (0.15)0.06 (0.11)0.10 (0.14)0.01 (0.07)0.0720.8790.072
Refractive values
MRSE (D)−0.54 (1.63)− 0.05 (1.87)−1.30 (3.15)0.66 (2.23)0.4640.5860.100
Manifest Sphere (D)0.41 (1.53)1.65 (1.90)0.02 (2.58)2.03 (2.20)0.7330.5480.053
Manifest Cylinder (D)−1.91 (1.17)−3.40 (2.11)−2.63 (1.87)− 2.73 (1.60)0.0510.7580.890
Curvature Values
Cylinder (D)3.24 (1.98)4.03 (2.22)3.85 (2.49)4.56 (1.92)0.4510.9450.450
K1 (D)41.64 (2.67)43.20 (2.29)41.00 (3.09)42.77 (1.43)0.0610.1620.104
K2 (D)44.88 (3.63)47.23 (3.08)44.85 (4.81)47.33 (2.43)0.1550.0800.145
Kmax (D)48.57 (4.49)53.70 (4.52)49.69 (5.42)53.00 (4.94)0.7960.0230.131
Aberrometric Values
Cornea Total
RMS total (μm)1.62 (0.82)2.72 (1.35)2.22 (1.15)2.81 (1.52)0.1240.8600.272
RMS LOA (μm)1.57 (0.80)2.61 (1.31)2.15 (1.12)2.72 (1.46)0.1230.9110.272
RMS HOA (μm)0.40 (0.19)0.73 (0.36)0.53 (0.29)0.70 (0.43)0.1910.2280.239
RMS Coma-like (μm)0.31 (0.21)0.65 (0.36)0.46 (0.32)0.57 (0.47)0.1470.0870.508
Anterior corneal surface
RMS total (μm)1.70 (0.93)2.98 (1.34)2.23 (1.15)2.96 (1.51)0.1810.3030.175
RMS LOA (μm)1.65 (0.92)2.88 (1.29)2.17 (1.12)2.86 (1.45)0.1770.3110.185
RMS HOA (μm)0.40 (0.21)0.79 (0.36)0.51 (0.27)0.74 (0.43)0.3380.2890.105
RMS Coma-like (μm)0.32 (0.22)0.72 (0.36)0.47 (0.29)0.66 (0.44)0.2030.1850.171
Posterior corneal surface
RMS total (μm)0.83 (0.25)0.81 (0.29)0.91 (0.26)0.82 (0.29)0.6080.8710.419
RMS LOA (μm)0.79 (0.24)0.77 (0.28)0.87 (0.25)0.78 (0.28)0.5230.9180.403
RMS HOA (μm)0.24 (0.08)0.23 (0.09)0.26 (0.08)0.23 (0.090.3430.8940.384
RMS Coma-like (μm)0.23 (0.14)0.20 (0.08)0.22 (0.14)0.19 (0.10)0.4530.8850.579
Densitometric Values
0.0–2.0 mm24.49 (5.43)25.70 (6.89)26.04 (8.89)26.88 (8.52)0.7000.8260.814
2.0–6.0 mm18.53 (2.40)18.69 (2.65)19.03 (4.08)18.71 (3.54)0.8070.4320.840
  1. * based on patients providing data to both time points
  2. BSCVA= best spectacle-corrected visual acuity; Coma-like= primary and secondary coma aberration; CXL= corneal cross-linking; CXL-Plus= central corneal regularization combined with CXL; HOA= higher order aberrations; K1 flattest meridian, K2= steepest meridian, Kmax= steepest radius of anterior curvature; LOA= lower order aberrations; MRSE= mean refractive spherical equivalent; RMS= root mean square; UDVA= uncorrected distance visual acuity. The results are expressed as means (standard deviation). The level of statistical significance was set at p = ≤; 0.05. p1 = the difference within the CXL-Plus group between postoperative values at 12 and 24 months postoperatively, p2 = the difference within the CXL-Plus group between postoperative values at 12 and 24 months postoperatively, p3 = the difference between CXL-Plus values and CXL alone values 24 months postoperatively