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Table 3 Comparison of posterior corneal elevation values by fitting the corneal shape to a best-fit sphere or best-fit toric ellipsoid reference surface between eyes that underwent combined transepithelial photorefractive keratectomy and accelerated corneal collagen cross-linking and transepithelial photorefractive keratectomy alone

From: Changes in posterior corneal elevations after combined transepithelial photorefractive keratectomy and accelerated corneal collagen cross-linking: retrospective, comparative observational case series

 

PRK-CXL group (n = 40)

PRK group (n = 42)

P b

Pre

6 mon

Δ

P a

Pre

6 mon

Δ

P a

Peripheral zone

 Post. elevation (μm, BFS)

–4.46 ± 4.37

–3.72 ± 4.58

0.75±1.58

.005

–3.79±4.46

–1.16±4.99

2.63±3.24

<.001

.001

 Post. elevation (μm, BFTE)

–0.38 ± 4.45

0.12±4.40

0.50±1.35

.024

0.59±4.44

2.61±5.22

2.02±3.43

<.001

.010

Central zone

 Post. elevation (μm, BFS)

4.11±5.80

0.23±5.46

–3.88 ± 4.84

<.001

3.30±7.28

–2.52 ± 7.01

–5.82 ± 8.81

<.001

.220

 Post. elevation (μm, BFTE)

1.31 ± 6.67

–2.16 ± 5.32

–3.47 ± 4.86

<.001

–1.26±7.33

–8.17 ± 7.59

–6.90 ± 9.90

<.001

.049

Max. elevation

 Post. elevation (μm, BFS)

20.28 ± 7.18

20.95 ± 7.80

0.68±5.34

.429

19.5±7.19

22.26 ± 9.64

2.69±6.35

.009

.124

 Post. elevation (μm, BFTE)

9.10±3.36

7.78±4.00

–1.33±4.08

.047

9.29±3.93

10.88±3.51

1.60±5.31

.059

.007

  1. PRK-CXL = Combined transepithelial photorefractive keratectomy and accelerated corneal collagen cross-linking; PRK = transepithelial photorefractive keratectomy; Δ = change; Peripheral zone = measurements of 6-mm and 4-mm zone; BFS = best-fit sphere; BFTE = best-fit toric ellipsoid; Central zone = measurements of 2-mm zone and center; Max. elevation = measurements of maximal elevation zone
  2. aP value between preoperative and 6-month postoperative corneal elevation values in each group
  3. bP value between changes in preoperative and postoperative corneal elevation values of PRK-CXL and PRK group