6.0D

Changes of Axial Length
After LASIK Surgery:
A 3-Year Follow-Up Study
Yoshinori Nakai, Osamu Hieda, and Shigeru Kinoshita
Department of Ophthalmology
Kyoto Prefectural University of Medicine
Kyoto, Japan
Background
Regression can occur after LASIK surgery even
without obvious complications during or after
the procedure.
Corneal epithelium over-formation (change of thickness)
Forward displacement of the posterior cornea
Lens stiffening
Axial length elongation?
•
•
•
•
•
Lohmann CP. Regression after LASIK for the treatment of myopia: the role of the
corneal epithelium. Semin Ophthalmol. 1998;13:79-82.
Spadea L. Role of the corneal epithelium in refractive changes following laser in situ
keratomileusis for high myopia. J Refract Surg. 2000;16:133-9.
Kozak I. Changes in central corneal thickness after laser in situ keratomileusis and
photorefractive keratectomy. J Refract Surg. 2003;19:149-53.
Ciolino JB. Changes in the posterior cornea after laser in situ keratomileusis and
photorefractive keratectomy. J Cataract Refract Surg. 2006;32:1426-31.
Seitz B. Posterior corneal curvature changes after myopic laser in situ keratomileusis.
Ophthalmology. 2001;108:666-72; discussion 673.
Purpose
To investigate the changes of axial length and
corneal curvature after LASIK surgery.
Subjects
• 544 eyes（286 cases: 147 males, 139 females）of
Japanese patients who were followed up for 3
years postoperatively.
• Mean patient age: 37.4 years（range: 20-72 years）
Methods
• Axial length was determined by ultrasound Amode (TOMEY) and IOL-Master® (Zeiss).
• Corneal curvature was determined by ARK700A® (NIDEK).
• A comparative study was then made between
higher myopia（≤-6.0D）and low-moderate
myopia（-6.0D<）.
Mean of Preoperative DATA
•
•
•
•
UCDVA: 0.05; CDVA: 1.3
Spherical Equivalent (S.E.): -6.0(±2.8)D
Axial Length: 26.09(±1.3)mm
Corneal Curvature: Kw42.8(±2.4)D;
Ks44.1(±2.5)D; Kave.43.4(±2.4)D
≤-6.0D: 146 cases, 276 eyes
A-mode: 133 cases, 254 eyes
IOL-Master ®: 13 cases, 22 eyes
-6.0D<: 140 cases, 268 eyes
A-mode: 131 cases, 248 eyes
IOL-Master ®: 9 cases, 20 eyes
Examinations
•
Postoperative to 3-Years Postoperative
 UCDVA and CDVA
 Spherical Equivalent (S.E.)
 Axial Length
 Corneal Curvature (Kw, Ks, Kave.)
•
Correlation between Regression (Changes of 1-Year to 3Years Postoperative) and…
Axial length elongation
Changes of corneal curvature
Patient age at the time of surgery
Visual Acuity
10
1
1.35
1.28
1.44
1.30 1.35
1.05
1.46
1.26 1.36
1.01
1.45
1.26 1.35
0.94
≤-6.0D
>-6.0D
0.1
0.08
0.03
0.01
Spherical Equivalent (S.E.)
（D）
*
*
2
*
**
**
0
PRE
1Y
2Y
3Y
-2
-4
≤-6.0D
>-6.0D
-6
-8
-10
* p<0.001
** p<0.01
Axial Length (A-mode)
（mm）
*
**
29
28
27
26
<-6.0D
25
>-6.0D
24
23
22
PRE
1Y
2Y
3Y
* p<0.01
** p<0.05
Axial Length (IOL-Master®)
**
**
29
**
28
27
26
≤-6D
25
>-6D
24
23
22
PRE
1Y
2Y
3Y
* p<0.01
** p<0.05
Corneal Curvature
≤-6.0D
（D）
46
**
*
44
44
42
42
*
*
*
40
**
*
Kw
Ks
Ka
38
34
34
2Y
3Y
*
*
Kw
Ks
Ka
38
36
1Y
**
*
40
36
PRE
>-6.0D
（D）
46
PRE
1Y
2Y
3Y
* p<0.01
** p<0.05
1- and 3-Year Postoperative Changes
≤-6.0D
Post 1Y
Post 3Y
-6.0D<
Post 1Y
Post 3Y
S.E.
-0.44(±0.76)
-0.60(±0.90)
S.E.
-0.13(±0.36)
-0.19(±0.42)
AL
26.84(±1.22)
26.84(±1.16)
AL
25.44(±0.96) 25.48(±1.02)
Kave.
38.55(±1.56)
38.67(±1.58)
Kave
40.40(±1.57) 40.44(±1.61)
P<0.01
P<0.05
Correlation with Regression (P value)
≤-6.0D
P value
-6.0D<
P value
AL
0.516
AL
0.078
Kave.
<0.001
Kave
0.793
Y.O.
0.456
Y.O.
0.690
Summary
• Regression had occurred by the end of the 3rd
postoperative year.
• Axial length had elongated approximately 0.1mm
by the end of the 1st postoperative year.
• A significant correlation was found between
regression and changes of corneal curvature in
cases of higher myopia (≤-6.0D).
Conclusion
• Not only changes of corneal curvature but also
the elongation of Axial Length might have to
be considered as the reason for regression
after LASIK surgery.
• The findings of this study might need to be
compared to further investigations involving
the measurement of more cases by IOLMaster®.

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