Transcript Reproducibility and Repeatability of Corneal Flap Thickness

Reproducibility and repeatability of corneal flap thickness
measured by anterior segment optical coherence
tomography
The authors have no financial interest in the subject matter
of this e-poster
Maria A Henriquez MD
Luis Izquierdo MD
Jackeline Parraga MD
PURPOSE
 To evaluate the interexaminer reproducibility and
intraexaminer repeatability in the measured of the flap
thickness obtained by anterior segment optical coherence
tomography (AS-OCT).
METHODS
• This prospective, randomized study included 128 eyes that
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underwent LASIK procedure.
3 months after an anterior segment OCT was performed.
2 different examiner performed the measurement at 0 mm, 3 mm
nasal and 3 mm temporal in a high resolution corneal at the axis
of 0° to 180°.
3 times for each examiner the measurement was done.
The repeatability and reproducibility of the measurements were
evaluated using intraclass correlation coefficients (ICCs) and the
Bland-Altman method.
AS-OCT scan with measurement of the flap thickness at 3 points.
3 mm nasal
Center
3 mm temporal
RESULTS
Examiner #1
Examiner #2
LOCALIZATION
Mean
SD*
Mean
SD *
0 mm
131.73 µm
38.78
145.93 µm
39.05
3 mm Nasal
142.41 µm
37.01
139.98 µm
47.8
3 mm Temporal
144.57 µm
40.55
141.92 µm
39.83
Table 1. Mean flap thickness at 0 mm, 3 mm nasal y 3 mm temporal points
(* standard deviation).
 The ICC was 0.75 having GOOD concordance
between the measurements.
Concordance according the intraclass
correlation coefficients (ICCs)
ICC: 0.75
ICC Value
Concordance
> 0.90
Very goog
0.71 - 0.90
Good
0.51 - 0.70
Moderate
0.31 - 0.50
Medium
< o.30
Bad
CONCLUSIONS
 Measurement of the flap thickness performed with the AS-OCT showed
good repeatability and reproducibility, showing that this device it is
accuracy in the preoperative evaluation of the patients before LASIK
enhancement.
REFERENCES
1.
Xu Y, Zhou X, Wang L, Xu H. A morphological study of corneal flap after thinflap laser-assisted in situ keratomileusis by anterior segment optical coherence
tomography. J Int Med Res. 2010;38(6):1952-60
2.
Zhang QW, et al. Analysis of flap thickness created with mechanical
microkeratome in LASIK by using anterior segment optical coherence
tomography. Zhonghua Yan Ke Za Zhi. 2010 Dec;46(12):1104-1109.
3.
Kucumen RB et al. AS-OCT as a tool for flap thickness measurement after
femtosecond-assisted LASIK. Ophthalmic Surg Lasers Imaging. 2011 Jan
1;42(1):31-6.
4.
Yu ZQ, et al. Analysis of flap thickness by anterior segment optical coherence
tomography in different flap preparation styles of excimer laser surgery.
Zhonghua Yan Ke Za Zhi. 2010 Mar;46(3):203-8. Chinese
5.
Bansal AS, Doherty T, Randleman JB, Stulting RD. Influence of flap thickness on
visual and refractive outcomes after laser in situ keratomileusis performed
with a mechanical keratome. J Cataract Refract Surg. 2010 May;36(5):810-3.
MARIA ALEJANDRA
HENRIQUEZ BERTAGGIA
• Medical School. ULA Merida. Venezuela. Magnacumlaude.
• Opthalmology Residency, Universidad Nacional Federico
Villarreal.Peru.
• Master in Ophthalmology. Universidad de Salta. Argentina.
• PhD in Medicine. USMP Lima Peru. .
• Medical Director of OFTALMOSALUD Institute of eyes. Lima- Pe
• Chief of Research Department at Oftalmosalud Insitute of Eyes.