Effects of error in radius of curvature on the corneal power measurement before and after laser refractive surgery for myopia

2012 ◽  
Vol 32 (4) ◽  
pp. 355-361 ◽  
Author(s):  
Yongji Liu ◽  
Yan Wang ◽  
Zhaoqi Wang ◽  
Tong Zuo
Keyword(s):  
Refractive Surgery ◽  
Power Measurement ◽  
Radius Of Curvature ◽  
Corneal Power ◽  
Before And After ◽  
Laser Refractive Surgery

New Scheimpflug camera device in measuring corneal power changes after myopic laser refractive surgery

2015 ◽  
Vol 38 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Michele Lanza ◽  
Stefania Iaccarino ◽  
Michela Cennamo ◽  
Alessandro Lanza ◽  
Giovanni Coen
Keyword(s):  
Refractive Surgery ◽  
Corneal Power ◽  
Scheimpflug Camera ◽  
Laser Refractive Surgery

scholarly journals Comparison between Point-Based and Ring-Based Technologies in Keratometric Measurement among Post Myopic Laser Refractive Surgery Patients

2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Md Muziman Syah ◽  
Aminul Hakim Sofian Sauri ◽  
Khairidzan Mohd Kamal ◽  
Mahfuzah Mokhtar
Keyword(s):  
Repeated Measures ◽  
Refractive Surgery ◽  
Intraclass Correlation ◽  
Corneal Power ◽  
Repeated Measures Analysis ◽  
Intraclass Correlations ◽  
Laser Refractive Surgery ◽  
Deviation Coefficient ◽  
Power Measurements ◽  
Intraocular Lens Calculation

Introduction: Corneal power or keratometric value represents two-third of total refractive power of the eye. It is an important parameter in intraocular lens calculation. Purpose of the study was to evaluate repeatability and agreement of keratometric measurements obtained from a six points-based keratometry device; IOLMaster 500 (Carl Zeiss Meditec AG, Jena, Germany) and two Placido disc-based keratometry devices; Atlas Topographer 995 and 9000 models (Carl Zeiss Meditec AG, Jena, Germany). Materials and method: A total of 97 post myopic laser refractive surgery subjects were recruited. Three set of mean corneal power measurements from each device were performed by an examiner in a single visit. The repeatability was evaluated by withinsubject standard deviation, coefficient of variation and intraclass correlation coefficient. A one-way repeated measures analysis of variance was conducted to evaluate keratometric measurement differences between the devices. The BlandAltman analysis was employed to assess inter-device agreement. Results: There were no significant differences of three repeated keratometric measurements in each device (p > 0.05). IOLMaster showed the lowest coefficient of variations in all meridians (< 0.30%).The intraclass correlations were higher than 0.90 in all devices. For inter-device agreement, there were statistically significant differences between Atlas 9000-IOLMaster and Atlas 995-IOLMaster (p < 0.05). The 95% limit of agreement ranged from 0.94 to 1.68. Conclusion: The six points-based technology has a higher repeatability compared to ring based technology in measuring postoperative keratometric measurements. Different keratometry technologies cannot be used interchangeably in clinical setting.

Algorithm for Correcting the Keratometric Error in the Estimation of the Corneal Power in Eyes With Previous Myopic Laser Refractive Surgery

Cornea ◽  
2013 ◽  
Vol 32 (11) ◽  
pp. 1454-1459 ◽  
Author(s):  
Vicente J. Camps ◽  
David P. Piñero ◽  
Veronica Mateo ◽  
David Ribera ◽  
Dolores de Fez ◽  
...  
Keyword(s):  
Refractive Surgery ◽  
Corneal Power ◽  
Laser Refractive Surgery

scholarly journals Clinical Validation of Adjusted Corneal Power in Patients with Previous Myopic Lasik Surgery

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Vicente J. Camps ◽  
David P. Piñero ◽  
Veronica Mateo ◽  
Celia García ◽  
Alberto Artola ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Clinical Significance ◽  
Refractive Surgery ◽  
Case Series ◽  
New Method ◽  
Clinical Validation ◽  
Retrospective Case ◽  
Corneal Power ◽  
Laser Refractive Surgery ◽  
Clinically Significant

Purpose. To validate clinically a new method for estimating the corneal power (Pc) using a variable keratometric index (nkadj) in eyes with previous laser refractive surgery.Setting. University of Alicante and Medimar International Hospital (Oftalmar), Alicante, (Spain).Design. Retrospective case series.Methods. This retrospective study comprised 62 eyes of 62 patients that had undergone myopic LASIK surgery. An algorithm for the calculation ofnkadjwas used for the estimation of the adjusted keratometric corneal power (Pkadj). This value was compared with the classical keratometric corneal power (Pk), the True Net Power (TNP), and the Gaussian corneal power (PcGauss). Likewise,Pkadjwas compared with other previously described methods.Results. Differences betweenPcGaussandPcvalues obtained with all methods evaluated were statistically significant (p<0.01). Differences betweenPkadjandPcGausswere in the limit of clinical significance (p<0.01, loA [−0.33,0.60] D). Differences betweenPkadjand TNP were not statistically and clinically significant (p=0.319, loA [−0.50,0.44] D). Differences betweenPkadjand previously described methods were statistically significant (p<0.01), except withPcHaigisL(p=0.09, loA [−0.37,0.29] D).Conclusion. The use of the adjusted keratometric index (nkadj) is a valid method to estimate the central corneal power in corneas with previous myopic laser refractive surgery, providing results comparable toPcHaigisL.

scholarly journals Optical Coherence Tomography Accurately Measures Corneal Power Change from Laser Refractive Surgery

Ophthalmology ◽  
2015 ◽  
Vol 122 (4) ◽  
pp. 677-686 ◽  
Author(s):  
Ryan P. McNabb ◽  
Sina Farsiu ◽  
Sandra S. Stinnett ◽  
Joseph A. Izatt ◽  
Anthony N. Kuo
Keyword(s):  
Optical Coherence Tomography ◽  
Refractive Surgery ◽  
Optical Coherence ◽  
Corneal Power ◽  
Power Change ◽  
Laser Refractive Surgery
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