Repeatability of corneal parameters with Pentacam after laser in situ keratomileusis.
OBJECTIVE
To investigate the coefficient of repeatability (CR) for corneal parameters evaluated with Pentacam after laser in situ keratomileusis (LASIK) in myopic eyes.


METHODS
Prospective, non-interventional, non-comparative study in an institutional setup.


METHODS
Forty eyes of 40 consecutive subjects who had undergone LASIK for myopia were assessed with the Scheimpflug system (Pentacam 70700: Oculus, Wetzlar Germany). The mean of five consecutive measurements of all the corneal parameters was recorded and CR was calculated as standard deviation of the difference from the mean of these repeat measurements divided by the mean response. The statistical significance of the CR was calculated for these parameters at 5% significance level.


RESULTS
The best CR was observed for the periphery of the anterior corneal curvature (0.18%) and the least for the horizontal meridian of the posterior corneal curvature (1.29%). Despite being significantly different ( P < 0.001), both the measurements were highly repeatable in post-LASIK eyes. The central, apical and minimal corneal thickness had a CR of 1%, 0.78% and 0.77% respectively. These were equally repeatable ( P> 0.323). The CR of the mean radius of curvature of the anterior cornea (0.29%) was significantly better ( P < 0.001) than the posterior corneal curvature (0.57%).


CONCLUSIONS
The CR for the post-LASIK cornea with Pentacam was the best for the anterior corneal curvature. Significantly, Pentacam has a high degree of repeatability for the posterior corneal curvature, which has a potential for early detection of keratectasia in these eyes. Post-LASIK pachymetry with Pentacam also showed excellent repeatability.
Jain
Rajeev
R
Grewal Eye Institute, Sector 9-C, Madhya Marg, Chandigarh - 160 009, India.
Dilraj
Grewal
G
Grewal
Satinder Pal Singh
SP
D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation* / Q000706:statistics & numerical data; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008297:Male; D009216:Myopia / Q000473:pathology / Q000601:surgery*; D015588:Observer Variation; D011184:Postoperative Period; D011446:Prospective Studies
J Cataract Refract Surg. 2001 Nov;27(11):1796-802
11709254
J Cataract Refract Surg. 2001 May;27(5):681-5
11377895
J Cataract Refract Surg. 2002 Feb;28(2):253-8
11821206
Ophthalmic Physiol Opt. 2002 Nov;22(6):552-9
12477020
Ophthalmology. 2003 Mar;110(3):511-5
12623813
Zhonghua Yan Ke Za Zhi. 2003 Jan;39(1):36-40
12760812
Clin Exp Optom. 2004 Jan;87(1):15-8
14720115
Br J Ophthalmol. 2004 Apr;88(4):466-8
15031156
J Cataract Refract Surg. 2004 May;30(5):1067-72
15130645
Lancet. 1986 Feb 8;1(8476):307-10
2868172
Ophthalmology. 1999 Feb;106(2):406-9; discussion 409-10
9951499
J Cataract Refract Surg. 2004 Nov;30(11):2251; author reply 2251-2
15519055
J Cataract Refract Surg. 2005 Jan;31(1):61-71
15721697
Clin Experiment Ophthalmol. 2005 Apr;33(2):147-52
15807822
J Cataract Refract Surg. 2005 Mar;31(3):571-3
15811747
Optom Vis Sci. 2005 Sep;82(9):858-61
16189497
Cornea. 2005 Nov;24(8):920-4
16227833
J Cataract Refract Surg. 2005 Sep;31(9):1729-35
16246776
J Cataract Refract Surg. 2005 Oct;31(10):1854
16338536
Ophthalmology. 2006 Sep;113(9):1629-32
16949447
Ophthalmology. 2007 Jun;114(6):1104-10
17239440
Br J Ophthalmol. 1999 Jul;83(7):774-8
10381661
Curr Opin Ophthalmol. 2000 Aug;11(4):273-9
10977772
Ophthalmology. 2001 Feb;108(2):317-20
11158806
J Cataract Refract Surg. 2001 Nov;27(11):1823-8
11709257