Use of the posterior/anterior corneal curvature radii ratio to improve the accuracy of intraocular lens power calculation: Eom’s adjustment method

Mingue Kim; Youngsub Eom; Hwa Lee; Young Woo Suh; Jong Suk Song; Hyo Myung Kim

doi:10.1167/iovs.17-22405

Use of the posterior/anterior corneal curvature radii ratio to improve the accuracy of intraocular lens power calculation: Eom’s adjustment method

Mingue Kim, Youngsub Eom, Hwa Lee, Young Woo Suh, Jong Suk Song, Hyo Myung Kim

Research output: Contribution to journal › Article › peer-review

18 Citations (Scopus)

Abstract

PURPOSE. To evaluate the accuracy of IOL power calculation using adjusted corneal power according to the posterior/anterior corneal curvature radii ratio. METHODS. Nine hundred twenty-eight eyes from 928 reference subjects and 158 eyes from 158 cataract patients who underwent phacoemulsification surgery were enrolled. Adjusted corneal power of cataract patients was calculated using the fictitious refractive index that was obtained from the geometric mean posterior/anterior corneal curvature radii ratio of reference subjects and adjusted anterior and predicted posterior corneal curvature radii from conventional keratometry (K) using the posterior/anterior corneal curvature radii ratio. The median absolute error (MedAE) based on the adjusted corneal power was compared with that based on conventional K in the Haigis and SRK/T formulae. RESULTS. The geometric mean posterior/anterior corneal curvature radii ratio was 0.808, and the fictitious refractive index of the cornea for a single Scheimpflug camera was 1.3275. The mean difference between adjusted corneal power and conventional K was 0.05 diopter (D). The MedAE based on adjusted corneal power (0.31 D in the Haigis formula and 0.32 D in the SRK/T formula) was significantly smaller than that based on conventional K (0.41 D and 0.40 D, respectively; P < 0.001 and P < 0.001, respectively). The percentage of eyes with refractive prediction error within ± 0.50 D calculated using adjusted corneal power (74.7%) was significantly greater than that obtained using conventional K (62.7%) in the Haigis formula (P = 0.029). CONCLUSIONS. IOL power calculation using adjusted corneal power according to the posterior/ anterior corneal curvature radii ratio provided more accurate refractive outcomes than calculation using conventional K.

Original language	English
Pages (from-to)	1016-1024
Number of pages	9
Journal	Investigative Ophthalmology and Visual Science
Volume	59
Issue number	2
DOIs	https://doi.org/10.1167/iovs.17-22405
Publication status	Published - 2018 Feb

Bibliographical note

Funding Information:
Supported by the Bumsuk Academic Research Fund in 2017. The funding source had no role in the design or conduct of this research.

Funding Information:
This work was presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO), Baltimore, MD, USA, May 7-11, 2017. Supported by the Bumsuk Academic Research Fund in 2017. The funding source had no role in the design or conduct of this research.

Publisher Copyright:
© 2018 The Authors.

Keywords

Calculation
Cataract
Corneal power
Intraocular lens
Posterior corneal radius

ASJC Scopus subject areas

Ophthalmology
Sensory Systems
Cellular and Molecular Neuroscience

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10.1167/iovs.17-22405

Cite this

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title = "Use of the posterior/anterior corneal curvature radii ratio to improve the accuracy of intraocular lens power calculation: Eom{\textquoteright}s adjustment method",

abstract = "PURPOSE. To evaluate the accuracy of IOL power calculation using adjusted corneal power according to the posterior/anterior corneal curvature radii ratio. METHODS. Nine hundred twenty-eight eyes from 928 reference subjects and 158 eyes from 158 cataract patients who underwent phacoemulsification surgery were enrolled. Adjusted corneal power of cataract patients was calculated using the fictitious refractive index that was obtained from the geometric mean posterior/anterior corneal curvature radii ratio of reference subjects and adjusted anterior and predicted posterior corneal curvature radii from conventional keratometry (K) using the posterior/anterior corneal curvature radii ratio. The median absolute error (MedAE) based on the adjusted corneal power was compared with that based on conventional K in the Haigis and SRK/T formulae. RESULTS. The geometric mean posterior/anterior corneal curvature radii ratio was 0.808, and the fictitious refractive index of the cornea for a single Scheimpflug camera was 1.3275. The mean difference between adjusted corneal power and conventional K was 0.05 diopter (D). The MedAE based on adjusted corneal power (0.31 D in the Haigis formula and 0.32 D in the SRK/T formula) was significantly smaller than that based on conventional K (0.41 D and 0.40 D, respectively; P < 0.001 and P < 0.001, respectively). The percentage of eyes with refractive prediction error within ± 0.50 D calculated using adjusted corneal power (74.7%) was significantly greater than that obtained using conventional K (62.7%) in the Haigis formula (P = 0.029). CONCLUSIONS. IOL power calculation using adjusted corneal power according to the posterior/ anterior corneal curvature radii ratio provided more accurate refractive outcomes than calculation using conventional K.",

keywords = "Calculation, Cataract, Corneal power, Intraocular lens, Posterior corneal radius",

author = "Mingue Kim and Youngsub Eom and Hwa Lee and Suh, {Young Woo} and Song, {Jong Suk} and Kim, {Hyo Myung}",

note = "Funding Information: Supported by the Bumsuk Academic Research Fund in 2017. The funding source had no role in the design or conduct of this research. Funding Information: This work was presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO), Baltimore, MD, USA, May 7-11, 2017. Supported by the Bumsuk Academic Research Fund in 2017. The funding source had no role in the design or conduct of this research. Publisher Copyright: {\textcopyright} 2018 The Authors.",

year = "2018",

month = feb,

doi = "10.1167/iovs.17-22405",

language = "English",

volume = "59",

pages = "1016--1024",

journal = "Investigative Ophthalmology and Visual Science",

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publisher = "Association for Research in Vision and Ophthalmology Inc.",

number = "2",

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T1 - Use of the posterior/anterior corneal curvature radii ratio to improve the accuracy of intraocular lens power calculation

T2 - Eom’s adjustment method

AU - Kim, Mingue

AU - Eom, Youngsub

AU - Lee, Hwa

AU - Suh, Young Woo

AU - Song, Jong Suk

AU - Kim, Hyo Myung

N1 - Funding Information: Supported by the Bumsuk Academic Research Fund in 2017. The funding source had no role in the design or conduct of this research. Funding Information: This work was presented in part at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO), Baltimore, MD, USA, May 7-11, 2017. Supported by the Bumsuk Academic Research Fund in 2017. The funding source had no role in the design or conduct of this research. Publisher Copyright: © 2018 The Authors.

PY - 2018/2

Y1 - 2018/2

N2 - PURPOSE. To evaluate the accuracy of IOL power calculation using adjusted corneal power according to the posterior/anterior corneal curvature radii ratio. METHODS. Nine hundred twenty-eight eyes from 928 reference subjects and 158 eyes from 158 cataract patients who underwent phacoemulsification surgery were enrolled. Adjusted corneal power of cataract patients was calculated using the fictitious refractive index that was obtained from the geometric mean posterior/anterior corneal curvature radii ratio of reference subjects and adjusted anterior and predicted posterior corneal curvature radii from conventional keratometry (K) using the posterior/anterior corneal curvature radii ratio. The median absolute error (MedAE) based on the adjusted corneal power was compared with that based on conventional K in the Haigis and SRK/T formulae. RESULTS. The geometric mean posterior/anterior corneal curvature radii ratio was 0.808, and the fictitious refractive index of the cornea for a single Scheimpflug camera was 1.3275. The mean difference between adjusted corneal power and conventional K was 0.05 diopter (D). The MedAE based on adjusted corneal power (0.31 D in the Haigis formula and 0.32 D in the SRK/T formula) was significantly smaller than that based on conventional K (0.41 D and 0.40 D, respectively; P < 0.001 and P < 0.001, respectively). The percentage of eyes with refractive prediction error within ± 0.50 D calculated using adjusted corneal power (74.7%) was significantly greater than that obtained using conventional K (62.7%) in the Haigis formula (P = 0.029). CONCLUSIONS. IOL power calculation using adjusted corneal power according to the posterior/ anterior corneal curvature radii ratio provided more accurate refractive outcomes than calculation using conventional K.

AB - PURPOSE. To evaluate the accuracy of IOL power calculation using adjusted corneal power according to the posterior/anterior corneal curvature radii ratio. METHODS. Nine hundred twenty-eight eyes from 928 reference subjects and 158 eyes from 158 cataract patients who underwent phacoemulsification surgery were enrolled. Adjusted corneal power of cataract patients was calculated using the fictitious refractive index that was obtained from the geometric mean posterior/anterior corneal curvature radii ratio of reference subjects and adjusted anterior and predicted posterior corneal curvature radii from conventional keratometry (K) using the posterior/anterior corneal curvature radii ratio. The median absolute error (MedAE) based on the adjusted corneal power was compared with that based on conventional K in the Haigis and SRK/T formulae. RESULTS. The geometric mean posterior/anterior corneal curvature radii ratio was 0.808, and the fictitious refractive index of the cornea for a single Scheimpflug camera was 1.3275. The mean difference between adjusted corneal power and conventional K was 0.05 diopter (D). The MedAE based on adjusted corneal power (0.31 D in the Haigis formula and 0.32 D in the SRK/T formula) was significantly smaller than that based on conventional K (0.41 D and 0.40 D, respectively; P < 0.001 and P < 0.001, respectively). The percentage of eyes with refractive prediction error within ± 0.50 D calculated using adjusted corneal power (74.7%) was significantly greater than that obtained using conventional K (62.7%) in the Haigis formula (P = 0.029). CONCLUSIONS. IOL power calculation using adjusted corneal power according to the posterior/ anterior corneal curvature radii ratio provided more accurate refractive outcomes than calculation using conventional K.

KW - Calculation

KW - Cataract

KW - Corneal power

KW - Intraocular lens

KW - Posterior corneal radius

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JO - Investigative Ophthalmology and Visual Science

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Use of the posterior/anterior corneal curvature radii ratio to improve the accuracy of intraocular lens power calculation: Eom’s adjustment method

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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