Journal List > J Korean Ophthalmol Soc > v.51(3) > 1008749

TOOLS
Lee, Park, and Shin: Comparison of Keratometric Values Measured by the Handheld Autokeratometer, On-table Autokeratometer and Manual Keratometer
Original Article

J Korean Ophthalmol Soc 2010;51(3):328-332.

Published online: 25 September 2010

DOI: https://doi.org/10.3341/jkos.2010.51.3.328

Comparison of Keratometric Values Measured by the Handheld Autokeratometer, On-table Autokeratometer and Manual Keratometer

Kyung-Min Lee, MD, Shin-Hae Park, MD, Sun-Young Shin, MD

Department of Ophthalmology and Visual Science, The Catholic University of Korea College of Medicine, Seoul, Korea

Address reprint requests to Sun-Young Shin, MD Department of Ophthalmology and Visual Science, St. Mary's Hospita, The Catholic University #505 Banpo-dong, Seocho-gu, Seoul 137-701, Korea Tel: 822-2588-1188, Fax: 822-599-7405, E-mail: eyeshin@catholic.ac.kr

Received 13 August 2009       Accepted 29 October 2009

Copyright © 2010 Korean Ophthalmological Society

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To compare the keratometry measurements by the handheld Nikon Retinomax K-plus2, the on-table Canon RK-5 autokeratometer, and the manual Topcon OM-4 keratometer and to evaluate the degree of agreement among the three instruments.

Methods

Adults (n=30) and children (n=40) presenting toa tertiary eye hospital clinic were examined by an optometrist. Topcon OM-4 keratometer, Nikon Retinomax and the on-table Canon RK-5 autokeratometer analyses were performed in order. The horizontal and vertical keratometry data were measured. The vector components of astigmatism, mean bias and agreement among the three types of measurements were evaluated.

Results

There were no significant differences among the three keratometers in horizontal or vertical keratometry or in central corneal astigmatism in both the adult and child groups (p-value>0.05). The keratometers which were estimated with Retinomax K-plus2 were highly correlated with those by on-table RK-5 autokeratometer (min. 0.89, max. 0.97) and Topcon OM-4 keratometer (min. 0.67, max. 0.94) in the adult group, while in the child group, the three instruments showed slightly decreased correlation (min. 0.45, max. 0.97 on RK-5, min. 0.36, max. 0.92 on OM-4), especially in the left eyes.

Conclusions

The handheld Retinomax K-plus2 provided comparable data to that of the conventional on-table Topcon and manual keratometers. This instrument will beuseful in the clinic to measure keratometry in children or immobilized patients who have difficulty sitting during the examination.

Keywords: Autokeratometer, Hand-held keratometer, Manual keratometer, Retinomax K-plus2

References

1. Lloyd IC, Goss-Sampson M, Jeffrey BG, et al. Neonatal cataract: aetiology, pathogenesis, and management. Eye. 1992; 6:184–96.
crossref
2. Cho CW, Kim SJ, Park YG. The utility of hand held autorefractometer for refraction in children. J Korean Ophthalmol Soc. 1997; 38:1044–9.
3. La TY, Oh JR. Reliability of Refractive Measurement by Hand-held Autorefractor. J Korean Ophthalmol Soc. 2002; 43:2241–5.
4. Kim M, Choi YS, Lu WN, et al. The developement of an objective test for visual acuity assessment using optokinetic nystagmus stimuli presented head – mounted display: Seohan objective visual acuity test. J Korean Ophthalmol Soc. 2000; 41:871–8.
5. Noonan CP, Raop GP, Kaye SB, et al. Validation of a handheld automated keratometer in adults. J Cataract Refract Surg. 1998; 24:411–44.
crossref
6. Manning CA, Kloess PM. Comparison of portable automated keratometry and manual keratometry for IOL calculation. J Cataract Refract Surg. 1997; 23:1213–6.
crossref
7. Sunderraj P. Clinical comparison of automated and manual keratometry in preoperative ocular biometry. Eye. 1992; 6:60–2.
crossref
8. Liang CL, Hung KS, Park N, et al. Comparison of the handheld Retinomax K-Plus2 and on-table autokeratometers in children with and without cycloplegia. J Cataract Refract Surg. 2004; 30:669–74.
crossref
9. Farook M, Venkatramani J, Gazzard G, et al. Comparisons of the Handheld Autorefractor, Table-Mounted Autorefractor, and Subjective Refraction in Singapore Adults. Optom Vis Sci. 2005; 82:1066–70.
crossref
10. Cordonnier M, De Maertelaer V. Comparison between two hand-held autorefractors: the Sure-Sight and the Retinomax. Strabismus. 2004; 12:261–74.
crossref
11. Lam AK, Chan R, Chiu R. Effect of instrument rotation on handheld keratometry. J Cataract Refract Surg. 2004; 30:2590–4.
crossref

Figure 1.
Composition of Retimax K-plus2.
jkos-51-328f1.tif
Table 1.
Mean, mean difference, and 95% LoA between 2 measurements by the retinomax K-plus and canon RK-5 (mean difference=data by the RK-5 minus data by retinomax
Keratometer Horizontal
 Vertical
 Astigmatism
Right
 Left
 Right
 Left
 Right
 Left
Child Adult Child Adult Child Adult Child Adult Child Adult Child Adult
Retinomax 43.10±1.87 42.62±1.26 42.14±6.95 42.60±1.26 44.38±2.11 43.27±1.12 44.32±2.77 43.26±1.16 1.28±0.70 0.65±0.98 2.18±5.00 0.66±1.09
Canon RK-5 43.04±1.76 42.72±1.32 43.02±1.73 42.24±1,27 44.48±2.14 43.40±1.01 44.68±2.13 43.03±1,48 1.34±0.79 0.68±1.23 1.66±0.89 0.79±1.38
Mean difference –0.06±0.26 0.088±0.56 0.88±6.76 –0.36±0.39 0.10±0.44 0.13±0.27 0.36±1.58 –0.22±0.54 0.06±0.46 0.037±0.57 –0.52±5.20 0.13±0.59
95% LoA –0.14∼0.02 –0.12–0.30 –1.08∼3.04 –0.50∼−0.21 –0.04∼0.24 0.025–0.23 –0.15∼0.86 –0.43∼−0.02 –0.09∼0.21 –0.18–0.25 –1.18∼1.14 –0.087∼0.35
Correlation 0.97 0.91 0.48 0.95 0.97 0.97 0.62 0.94 0.81 0.89 0.45 0.91
Paired t-test 0.47 0.37 0.11 0.42 0.53 0. 46 0.26 0.62 0.38 0.32 0.09 0.53
Table 2.
Mean, mean difference, and 95% LoA between 2 measurements by the retinomax K-plus and topcon OM-4 (mean difference=data by the OM-4 minus data by retinomax)
Keratometer Horizontal
 Vertical
 Astigmatism
Right
 Left
 Right
 Left
 Right
 Left
Child Adult Child Adult Child Adult Child Adult Child Adult Child Adult
Retinomax 43.10±1.87 42.63±1.26 42.14±6.95 42.60±1.26 44.38±2.11 43.27±1.12 44.32±2.77 43.26±1.16 1.28±0.70 0.65±0.98 2.18±5.00 0.66±1.09
Topcon OM-4 43.24±1.73 42.38±1.12. 43.06±1.69 42.49±1.16 44.41±2.05 43.29±0.93 44.49±2.14 43.29±1.24 1.17±0.92 0.91±0.86 1.43±1.03 1.00±0.88
Mean difference 0.13±0.49 –0.25±0.68 0.92±6.67 –0.11±0.49 0.027±0.33 0.017±0,60 0.17±1.90 0.036±0.62 –0.11±0.57 0.26±1.00 –0.75±5.03 0.34±1.00
95% LoA –0.021∼0.29 –0.50∼0.009 –1.21∼2.05 –0.29∼−0.22 –0.079∼0.13 –0.21∼0.24 –0.44∼0.78 –0.20∼0.27 –0.29∼0.076 –0.11∼0.64 –1.36∼0.46 0.030∼0.52
Correlation 0.82 0.84 0.46 0.93 0.92 0.94 0.73 0.86 0.78 0.84 0.36 0.67
Paired t-test 0.18 0.34 0.07 0.64 0.59 0.65 0.13 0.19 0.24 0.18 0.06 0.42
Table 3.
Mean, mean difference, and 95% LoA between 2 measurements by the topcon OM-4 and canon RK-5 (mean difference=data by the OM-4minus data by RK-5)
Keratometer Horizontal Vertical Astigmatism
Right Left Right Left Right Left
Child Adult Child Adult Child Adult Child Adult Child Adult Child Adult
Topcon OM-4 43.24±1.73 42.38±1.12. 43.06±1.69 42.49±1.16 44.41±2.05 43.29±0.93 44.49±2.14 43.29±1.24 1.17±0.92 0.91±0.86 1.43±1.03 1.00±0.88
Canon RK-5 43.04±1.76 42.72±1.32 43.02±1.73 42.24±1,27 44.48±2.14 43.40±1.01 44.68±2.13 43.03±1,48 1.34±0.79 0.68±1.23 1.66±0.89 0.79±1.38
Mean difference 0.20±0.42 –0.33±0.73 0.044±0.29 0.25±0.60 –0.07±0.37 –0.11±0.59 –0.18±0.92 0.26±0.83 –0.17±0.54 0.22±1.15 –0.23±0.91 0.21±1.21
95% LoA 0.07∼0.34 –0.51∼−0.061 –0.48∼0.11 –0.52∼0.17 –0.59∼−0.36 –0.33∼0.11 –0.48∼0.11 –0.050∼0.57 –1.14∼−0.80 –0.20∼0.45 –0.42∼0.062 –0.24∼0.46
Correlation 0.97 0.83 0.98 0.88 0.98 0.82 0.91 0.83 0.81 0.84 0.77 0.65
Paired t-test 0.59 0.48 0.62 0.47 0.54 0.52 0.51 0.39 0.31 0.44 0.12 0.10
TOOLS
Similar articles