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Table 1 Main results studies

From: Post-keratoplasty astigmatism management by relaxing incisions: a systematic review

Authors N Study type Treatment Location Refractive (R) or keratometric (K) cylinder Complications
Pre-op (D) Post-op (D) Reduction (%)
Krachmer & Fenzl, 1980 [52] 16 Retrospective, comparative case series Manual paired relaxing incision
Depth = 50% to 66% CCT
Length = 60°
Graft-host interface
Graft-host interface 10.11 (K) 5.79 (K) 43 (K) 2 perforations
Price & Whitson, 1991 [55] 111 Retrospective case series Manual paired relaxing incision
Depth and length variable
Graft or graft-host interface 6.18 ± 1.56 (R) 3.34 ± 1.96 (R) 46 (R) 12 wound dehiscences
Hjortdal & Ehlers, 1998 [56] 21 Nonrandomized retrospective study Manual relaxing incision
Depth = central corneal thickness
Length = 45°; 5 or 6 mm from optical zone
Graft 7 (R) 3.25 (R) 54 (R) None
Hannush et al., 1998 [57] 29 Retrospective case series Manual paired relaxing incision
Depth = 75% CCT
Length = not available
0.5 mm inside the graft-host interface
Graft 8.8 ± 3.1 (K) 3.2 ± 3.0 (K) 64 (K) None
Borderie et al., 1999 [58] 22 Retrospective case series Manual paired relaxing incision with Hanna arcitome
Depth = 75% thinnest pachymetry
Length = 60° to 80°
6 to 6.75 mm zone diameter (Hanna nomogram [38])
Graft 6.94 ± 2.11 (R) 3.85 ± 1.95 (R) 44 (R) 1 perforation, 1 overcorrection (same patient)
9.02 ± 2.67 (K) 3.94 ± 2.19 (K) 56 (K)
Koay et al., 2000 [59] 34 Nonrandomized retrospective study Manual relaxing incision and compression sutures
Depth = 480 μm
Length = 45°
Graft-host interface 9.69 ± 3.51 (R) 3.92 ± 2.16 (R) 59.5 (R) 1 graft rejection
9.14 ± 4.38 (K) 3.59 ± 1.92 (K) 60.7 (K)
Wilkins et al., 2005 [35] 20 Nonrandomized retrospective study Manual relaxing incision
Depth = 600 μm
Length = 60°; 6 mm from optical zone
Host 10.99 ± 4.26 (R) 3.33 ± 2.18 (R) 72 (R) None
Bochmann & Schipper, 2006 [12] 11 Nonrandomized retrospective study Manual relaxing incision
Depth = 80% of peripheral corneal thickness
Length = 30° to 90°
9 to 10 mm zone diameter
Host 6.1 ± 2.5 (R) 3.3 ± 0.7 (R) 45.9 (R) None
9.02 ± 3.54 (K) 3.41 ± 1.21 (K) 62.2 (K)
Geggel 2006, [50] 26 Nonrandomized retrospective observational case series Manual relaxing incision
Depth = 80% of the thinnest pachymetry on the meridian
Length = 35° to 90°
0.5 mm or 1 mm inside the graft-host junction if >10 D
Graft 8.7 ± 2.4 (K) 3.25 ± 1.74 (K) 63 (K) None
Poole & Ficker, 2006 [60] 39 Nonrandomized retrospective study Manual relaxing incision
Depth = 90% CCT
Length = 45° to 90°, 0.5 mm inside the graft-host interface
Graft 9.13 (R) 4.85 (R) 47 (R) 1 perforation
Hoffart et al., 2007 [61] 40 Nonrandomized retrospective study Manual relaxing incision
Depth = 75% CCT, length = 60° to 80°
6 to 6.75 mm zone diameter (Hanna nomogram [38])
Graft 8.84 ± 3 (R) 4.88 ± 2.5 (R) 45 (R) 1 perforation, 2 rejections
Bahar et al., 2008 [62] 40 Retrospective, comparative case series FS: Depth = 90% CCT
Length = 60° to 90°
0.5 mm inside the graft-host junction
Manual: Depth = 500 μm
Length = 45° to 90°
0.5 mm inside the graft-host junction
Graft FS: 7.84 ± 2.35 (K) FS: 3.58 ± 2.21 (K) FS: 54 (K) FS: 5 overcorrections, 1 rejection
Manual: 7.80 ± 3.14 (K) Manual: 4.58 ± 2.95 (K) Manual: 41 (K) 3 perforations,6 overcorrections, 1 infection
Buzzonetti et al., 2009 [63] 9 Prospective non- comparative study FS, paired symmetric incisions 90° angled
Depth = 80% thinnest pachymetry
Length = 70°
Optical zone = 4.8 to 6.8 mm
Graft 9.10 ± 3.90 (R) 3.10 ± 1.50 (R) 66 (R) None
9.80 ± 1.90 (K) 5.20 ± 1.50 (K) 47 (K)
Nubile et al., 2009 [64] 12 Prospective noncomparative interventional case series. FS, paired symmetric incisions 90° angled
Depth = 90% pachymetry on incision location
Length = 40° to 80 °
1 mm inside the graft-host junction
Graft 7.16 ± 3.07 (R) 2.39 ± 1.62 (R) 66 (R) 2 perforations
Hoffart et al., 2009 [39] 20 Prospective comparative randomized study FS or Hanna arcitome
Depth = 75% thinnest pachymetry
Length = 60° to 80°
6 to 6.75 mm zone diameter (Hanna nomogram [38])
Graft FS: 8.6 ± 3 (R) FS: 3.9 ± 2.4 (R) FS: 55 (R) 1 perforation
Hanna: 6.7 ± 2.1 (R) Hanna: 4.7 ± 2.4 (R) Hanna: 30 (R)
Kumar et al. 2010 [65] 34 Retrospective case series FS, paired symmetric incisions
Depth = 90% pachymetry on incision location
Length = 40° to 60 ° (<6 D), 65° to 75° (6 to 10 D), 90° (> 10 D)
0.5 mm inside the graft-host junction
Graft 7.46 ± 2.7 (K) 4.77 ± 3.29 (K) 36 (K) 3 rejections, 9 overcorrections (24%)
Fares et al., 2013 [66] 26 Nonrandomized prospective study Manual relaxing incision with compression suture
Depth = 80% CCT
Length = 45° (6 D to 9 D) to 60° (>9 D)
7 mm zone diameter
Interface 9.66 ± 2.9 (R) 4.37 ± 2.53 (R) 58.4 (R) 1 perforation
Cleary et al., 2013 [42] 6 Prospective noncomparative interventional case series FS beveled
Bevel angle of 135°
Depth = 65% to 75% CCT
Length = 60° to 90°
0.4 mm inside the graft margin
Graft 9.8 ± 2.9 (K) 4.5 ± 3.2 (K) 57 (K) None
Loriaut et al., 2015 [67] 20 Retrospective case series FS
Depth = 75% thinnest pachymetry
Length = 60° to 80°
6 to 6.8 mm zone diameter (Hanna nomogram [38])
Graft 9.45 ± 2.97 (K) 4.64 ± 2.79 (K) 50.9 (K) 10 overcorrections
Al Sabaani et al., 2016 [41] 52 Retrospective non-comparative interventional study FS
Depth = 75% - 85% thinnest pachymetry
Length = 50° to 70° (Nordan nomogram [41])
0.5-0.7 mm within the graft-host junction
Graft 7.15 ± 1.32 (R) 5.19 ± 2.25 (R) 27.4 (R) 3 perforations, 12 overcorrections
Hashemian et al., 2017 [68] 23 Prospective interventional case series FS
Depth = 85% thinnest pachymetry
Length = 40° to 90° (Wu [69] and Kumar [65] nomogram)
1 mm within the graft-host junction
Graft 7.79 ± 2.64 (R) 3.69 ± 2.25 (R) 52.6 (R) 2 perforations
  1. CCT = central corneal thickness; FS = femtosecond laser assisted