Table 2 Refractive outcomes, epithelial healing and haze grading of the two transepithelial PRK techniques.

From: Transepithelial photorefractive keratectomy: a prospective randomized comparative study between the two-step and the single-step techniques

Parameters

Two-step PTK-PRK (n = 50)

Single step TE-PRK (n = 50)

P valuea

UDVA logMARb

  Pre-operative

1.04 ± 0.19

1.03 ± 0.23

0.948

  Postop. 1 week

0.30 ± 0.01

0.10 ± 0.01

<0.001c

  Postop. 1 month

0.14 ± 0.01

0.04 ± 0.01

<0.001c

  Postop. 3 months

0.10 ± 0.01

0.03 ± 0.009

<0.001c

  Postop. 6 months

0.08 ± 0.01

0.03 ± 0.008

<0.001c

   P valued

<0.001c

<0.001c

 

   P valuee

<0.001c

0.25

 

CDVA logMARb

  Pre-operative

0.02 ± 0.006

0.02 ± 0.006

0.697

  Postop. 1 week

0.06 ± 0.009

0.03 ± 0.008

0.036c

  Postop. 1 month

0.03 ± 0.006

0.02 ± 0.007

0.459

  Postop. 3 months

0.02 ± 0.006

0.02 ± 0.006

0.771

  Postop. 6 months

0.03 ± 0.006

0.02 ± 0.006

0.645

   P valued

<0.001c

0.01c

 

   P valuee

0.3

0.3

 

Manifest sphere (D)b

  Pre-operative

−2.42 ± 0.18

−2.37 ± 0.25

0.548

  Postop. 1 week

−0.63 ± 0.05

0.08 ± 0.06

<0.001c

  Postop. 1 month

−0.39 ± 0.04

0.10 ± 0.04

<0.001c

  Postop. 3 months

−0.25 ± 0.04

0.10 ± 0.03

<0.001c

  Postop. 6 months

−0.23 ± 0.03

0.04 ± 0.02

<0.001c

   P valued

<0.001c

<0.001c

 

   P valuee

<0.001c

0.1

 

Manifest cylinder (D)b

  Pre-Operative

−1.50 ± 0.16

−1.26 ± 0.14

0.337

  Postop. 1 week

−0.82 ± 0.04

−0.28 ± 0.05

<0.001c

  Postop. 1 month

−0.64 ± 0.04

−0.21 ± 0.05

<0.001c

  Postop. 3 months

−0.59 ± 0.04

−0.17 ± 0.03

<0.001c

  Postop. 6 months

−0.43 ± 0.02

−0.17 ± 0.03

<0.001c

   P valued

<0.001c

<0.001c

 

   P valuee

<0.001c

0.337

 

MRSE (D)b

  Pre-operative

−3.17 ± 1.14

−2.99 ± 1.61

0.269

  Postop. 1 week

−1.03 ± 0.06

−0.05 ± 0.07

<0.001c

  Postop. 1 month

−0.71 ± 0.05

−0.003 ± 0.05

<0.001c

  Postop. 3 months

−0.53 ± 0.04

0.01 ± 0.04

<0.001c

  Postop. 6 months

−0.44 ± 0.03

−0.04 ± 0.03

<0.001c

   P valued

<0.001c

<0.001c

 

   P valuee

<0.001c

0.218

 

Epithelial healing daysb

P valuef

  Mean ± SD

5.48 ± 0.76

3.24 ± 0.43

<0.001c

  Range

(4.00–7.00)

(3.00–4.00)

 

  Median

5

3

 

Haze grade (3 mo)

Eyes n (%)

Eyes n (%)

P valueg

  0

30 (60%)

31 (62%)

0.89

  0.5

17 (34%)

17 (34%)

 

  1

3 (6%)

2 (4%)

 
  1. CDVA Corrected distance visual acuity, D Dioptres, MRSE Manifest refractive spherical equivalent, PTK-PRK Phototherapeutic keratectomy-photorefractive keratectomy, TE-PRK Transepithelial photorefractive keratectomy, UDVA Uncorrected distance visual acuity 1
  2. aIndependent Sample T-test to compare means between the two groups.
  3. bData expressed as Mean ± SD/SE.
  4. cStatistical significance.
  5. dOne-way repeated measure ANOVA test within each group effect: preop., 1 week, 1- month, 3 and 6 months postop.
  6. ePaired T-test to compare mean results between 1 month and 6 months follow up visits in each group.
  7. fMann–Whitney U test.
  8. gChi-Square test.
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