Jae Lim Chung MD, MBAJae Lim Chung MD, MBA1,31,3; Jin Pyo Hong MD; Jin Pyo Hong MD2,32,3; Kyoung Yul Seo MD, ; Kyoung Yul Seo MD, PhDPhD33; Eung Kweon Kim MD, PhD; Eung Kweon Kim MD, PhD33; Tae-im Kim MD, PhD; Tae-im Kim MD, PhD33

11Noo Ne Eye Hospital, Seoul, Korea22Sae Yan Eye Clinic, Seoul, Korea

33Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.

None of the authors have any commercial or financial interests

For Successful Outcome Of Toric IOL Precise Measurement Of Preoperative

Corneal Astigmatism Crucial Point !

To Determine Accuracy & Correlation of 6 Different Keratometers & Topographers

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Shin-Nippon Co, Ltd, Japan

Measuring capacityCorneal Radius of

Curvature ○ 6.50 ~ 9.40 mm

Corneal Keratometric Power ○ 36 ~ 52 D

Axis Corneal Astigmatism ○ 0 ~ 180°

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Canon, Japan Measuring capacity

Corneal Radius of Curvature ○ 5.5 ~ 10 mm

Corneal Refractive Power ○ 33.75 ~ 61.25 D

Axis Corneal Astigmatism ○ 0 ~ 180°

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• Carl Zeiss Meditec, Germany

• 2.5 mm measurement diameter• Cf. Manual keratometers ~ 3 mm

• 30 data points per measurement• 6 spots x 5 samples

5 images automatically captured in 0.5 sec

Displayed result is average of 5 captured images

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Bausch & Lomb, USA Topography-based Simulated K-readings

(=Sim K’s) c Axis 3 & 5 mm zone

statisticsAverage & SD of Mean &

Astigmatic Power Steep & Flat Axis

Oculus, Germany Scheimpflug image-

based Topographic analysis of Corneal Astigmatism

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Tracey Technologies, USA Dual Acquisition Unit

EysSys Corneal Topographer○ Placido ring-based

Wavefront analyzer

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Study PopulationPreoperative visit for Cataract Surgery257 eyes of 141 patients○ Age : 54.5 ± 20.5 yrs○ Sex : Male - 54, Female - 87

Manual Keratometric MeasurementDuplicated examination by 2 skillful

examinersConsidered as Standard

Compared with 5 other Keratometers9

Pearson Correlation analysis Between Manual Keratometery Vs Other Methods

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Vs. Manual Keratometer

Pearson Correlation Coefficient

iTrace 0.947

ORBscan 0.921AutoKeratometer 0.919IOL master 0.857

Pentacam 0.847

Pearson Correlation analysis Between Manual Keratometery Vs Other Methods

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Vs. Manual Keratometer

Pearson Correlation Coefficient

iTrace 0.856

AutoKeratometer 0.852IOL master 0.751ORBscan 0.646

Pentacam 0.633

Duplicated Manual Keratometric Measurements By 2 Experienced Operators Taken As Standard

iTrace Approximated This Standard The Most

Auto Keratometer, ORB & IOL Master Showed To Be Reasonably Accurate.

Trend For ORB Fail To Read Accurately In Steep Axis

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